[Federal Register Volume 88, Number 231 (Monday, December 4, 2023)]
[Rules and Regulations]
[Pages 84188-84232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-25921]



[[Page 84187]]

Vol. 88

Monday,

No. 231

December 4, 2023

Part II





 Department of Energy





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10 CFR Parts 429 and 431





Energy Conservation Program: Test Procedure for Water-Source Heat 
Pumps; Final Rule

  Federal Register / Vol. 88 , No. 231 / Monday, December 4, 2023 / 
Rules and Regulations  

[[Page 84188]]


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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0029]
RIN 1904-AE05


Energy Conservation Program: Test Procedure for Water-Source Heat 
Pumps

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Final rule.

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SUMMARY: The U.S. Department of Energy (``DOE'') is amending its test 
procedure for water-source heat pumps to expand the scope of 
applicability of the test procedure, incorporate by reference a new 
industry consensus test standard for water-source heat pumps, adopt a 
seasonal cooling efficiency metric, and specify more representative 
test conditions used for measuring heating performance. DOE has 
determined that the amended test procedure will produce results that 
are more representative of an average use cycle and be more consistent 
with current industry practice without being unduly burdensome to 
conduct. Additionally, DOE is adopting provisions governing public 
representations of efficiency for this equipment.

DATES: The effective date of this rule is January 3, 2024. The 
amendments will be mandatory for product testing starting November 29, 
2024.
    The incorporation by reference of certain material listed in the 
rule is approved by the Director of the Federal Register on January 3, 
2024.

ADDRESSES: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, comments, and other supporting 
documents/materials, is available for review at www.regulations.gov. 
All documents in the docket are listed in the www.regulations.gov 
index. However, not all documents listed in the index may be publicly 
available, such as those containing information that is exempt from 
public disclosure.
    A link to the docket web page can be found at www.regulations.gov/docket/EERE-2017-BT-TP-0029. The docket web page contains instructions 
on how to access all documents, including public comments, in the 
docket.
    For further information on how to review the docket contact the 
Appliance and Equipment Standards Program staff at (202) 287-1445 or by 
email: [email protected].

FOR FURTHER INFORMATION CONTACT: 
    Mr. Troy Watson, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Office, EE-5B, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(240) 449-9387. Email: [email protected].
    Ms. Kristin Koernig, U.S. Department of Energy, Office of the 
General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 
20585-0121. Telephone: (202) 586-3593. Email: 
[email protected].

SUPPLEMENTARY INFORMATION: DOE incorporates by reference the following 
material into 10 CFR parts 429 and 431:

AHRI Standard 600-2023 (I-P), 2023 Standard for Performance Rating of 
Water/Brine to Air Heat Pump Equipment, approved September 11, 2023 
(``AHRI 600-2023'').
ANSI/ASHRAE Standard 37-2009, Methods of Testing for Rating 
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment, 
ASHRAE-approved June 24, 2009 (``ANSI/ASHRAE 37-2009'').
Errata sheet for ANSI/ASHRAE Standard 37-2009, Methods of Testing for 
Rating Electrically Driven Unitary Air-Conditioning and Heat Pump 
Equipment, March 27, 2019.
ISO Standard 13256-1:1998, Water-source heat pumps--Testing and rating 
for performance--Part 1: Water-to-air and brine-to-air heat pumps, 
approved 1998 (``ISO 13256-1:1998'').
Properties of Secondary Working Fluids for Indirect Systems, including 
Section 2.3 Errata Sheet, Melinder, published 2010 (``Melinder 2010'').

    Copies of AHRI 600-2023 are available from the Air-Conditioning, 
Heating, and Refrigeration Institute (``AHRI''), 2311 Wilson Blvd., 
Suite 400, Arlington, VA 22201, (703) 524-8800, or by going to 
www.ahrinet.org.
    Copies of ANSI/ASHRAE 37-2009 and Errata sheet for ANSI/ASHRAE 
Standard 37-2009 are available from the American Society of Heating, 
Refrigerating, and Air-Conditioning Engineers (``ASHRAE''), 180 
Technology Parkway NW, Peachtree Corners, GA 30092, (404) 636-8400, or 
by going to www.ashrae.org. (ASHRAE standards are co-published with 
American National Standards Institute (``ANSI'')).
    Copies of ISO Standard 13256-1:1998 can be obtained from the 
International Organization for Standardization (``ISO''), Chemin de 
Blandonnet 8 CP 401, 1214 Vernier, Geneva, Switzerland, +41 22 749 01 
11, or online at: www.iso.org/store.html.
    Copies of Melinder 2010 are available from the International 
Institute of Refrigeration (``IIR''), 177 Boulevard Malesherbes 75017 
Paris, France; +33 (0)1 42 27 32 35; www.iifiir.org.
    See section IV.N of this document for further discussion of these 
standards.

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Final Rule
III. Discussion
    A. Scope of Applicability
    1. WSHPs With Cooling Capacity Greater Than or Equal to 135,000 
Btu/h
    2. Representations for Residential Applications
    B. Definition
    C. Organization of the Amended DOE Test Procedures
    D. Updates to Industry Standards
    1. Comments Regarding DOE's Authority
    2. Comments Regarding DOE's Test Procedure Development Process
    3. Comments Supporting the Adoption of AHRI 340/360-2022
    4. Comments Opposing the Adoption of AHRI 340/360-2022
    5. Comments Encouraging the Adoption of AHRI 600
    6. Finalized DOE Test Procedure
    E. Efficiency Metrics
    1. IEER
    2. ACOP
    3. Optional Representations
    4. Entering Air Conditions
    F. Test Method
    1. Airflow and External Static Pressure
    2. Capacity Measurement
    3. Pump Power Adjustment and Liquid External Static Pressure
    4. Test Liquid and Specific Heat Capacity
    5. Liquid Flow Rate
    6. Refrigerant Line Losses
    7. Airflow Measurement
    8. Air Condition Measurement
    9. Duct Losses
    10. Refrigerant Charging
    11. Voltage
    12. Non-Standard Low-Static Indoor Fan Motors
    G. Configuration of Unit Under Test
    1. Background and Summary
    2. General Comments Received
    3. Approach for Exclusion of Certain Components
    H. Represented Values and Enforcement
    1. Cooling Capacity
    2. Enforcement of IEER
    I. Test Procedure Costs
    J. Effective and Compliance Dates
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Orders 12866, 13563, and 14094
    B. Review Under the Regulatory Flexibility Act
    1. Description and Estimate of Small Entities Regulated
    2. Description and Estimate of Compliance Requirements

[[Page 84189]]

    3. Certification Statement
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under Treasury and General Government Appropriations 
Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Congressional Notification
    N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Authority and Background

    Water-source heat pumps (``WSHPs'') are a category of small, large, 
and very large commercial package air-conditioning and heating 
equipment,\1\ which are included in the list of ``covered equipment'' 
for which DOE is authorized to establish and amend energy conservation 
standards and test procedures. (42 U.S.C. 6311(1)(B)-(D); 
6313(a)(1)(G)-(I)) DOE's test procedure for WSHPs is currently 
prescribed at title 10 of the Code of Federal Regulations (``CFR'') 
part 431.96. The following sections discuss DOE's authority to 
establish and amend a test procedure for WSHPs and relevant background 
information regarding DOE's consideration of a test procedure for this 
equipment.
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    \1\ The Energy Policy and Conservation Act, as amended 
(``EPCA'') defines ``commercial package air conditioning and heating 
equipment'' as air-cooled, water-cooled, evaporatively-cooled, or 
water-source (not including ground-water-source) electrically 
operated unitary central air conditioners and central air 
conditioning heat pumps for commercial application. (42 U.S.C. 
6311(8)(A)) EPCA further defines ``small commercial package air 
conditioning and heating equipment'' as commercial package air 
conditioning and heating equipment that is rated below 135,000 Btu 
per hour (cooling capacity); ``large commercial package air 
conditioning and heating equipment'' as commercial package air 
conditioning and heating equipment that is rated at or above 135,000 
Btu per hour and below 240,000 Btu per hour (cooling capacity); and 
``very large commercial package air conditioning and heating 
equipment'' as commercial package air conditioning and heating 
equipment that is rated at or above 240,000 Btu per hour and below 
760,000 Btu per hour (cooling capacity). (42 U.S.C. 6311(8)(B)-(D))
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A. Authority

    The Energy Policy and Conservation Act, Public Law 94-163, as 
amended (``EPCA''),\2\ authorizes DOE to regulate the energy efficiency 
of a number of consumer products and certain industrial equipment. (42 
U.S.C. 6291-6317) Title III, Part C of EPCA,\3\ added by Public Law 95-
619, Title IV, section 441(a), established the Energy Conservation 
Program for Certain Industrial Equipment, which sets forth a variety of 
provisions designed to improve energy efficiency. This equipment 
includes WSHPs, the subject of this document. (42 U.S.C. 6311(1)(B)-
(D))
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    \2\ All references to EPCA in this document refer to the statute 
as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 
27, 2020), which reflect the last statutory amendments that impact 
Parts A and A-1 of EPCA.
    \3\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    The energy conservation program under EPCA consists essentially of 
four parts: (1) testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of EPCA include definitions (42 U.S.C. 6311), test 
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), 
energy conservation standards (42 U.S.C. 6313), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316; 42 
U.S.C. 6296).
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for: (1) 
certifying to DOE that their equipment complies with the applicable 
energy conservation standards adopted pursuant to EPCA (42 U.S.C. 
6316(b); 42 U.S.C. 6296), and (2) making other representations about 
the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE 
uses these test procedures to determine whether the equipment complies 
with relevant standards promulgated under EPCA.
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, 
grant waivers of Federal preemption for particular State laws or 
regulations, in accordance with the procedures and other provisions of 
EPCA. (42 U.S.C. 6316(b)(2)(D))
    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results which reflect energy efficiency, energy use or estimated annual 
operating cost of a given type of covered equipment during a 
representative average use cycle (as determined by the Secretary) and 
requires that test procedures not be unduly burdensome to conduct. (42 
U.S.C. 6314(a)(2))
    EPCA requires that the test procedures for commercial package air 
conditioning and heating equipment be those generally accepted industry 
testing procedures or rating procedures developed or recognized by the 
Air-Conditioning, Heating, and Refrigeration Institute (``AHRI'') or by 
the American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (``ASHRAE''), as referenced in ASHRAE 90.1, ``Energy Standard 
for Buildings Except Low-Rise Residential Buildings'' (``ASHRAE 
90.1''). (42 U.S.C. 6314(a)(4)(A)) Further, if such an industry test 
procedure is amended, DOE must update its test procedure to be 
consistent with the amended industry test procedure, unless DOE 
determines, by rule published in the Federal Register and supported by 
clear and convincing evidence, that such test procedure would not meet 
the requirements in 42 U.S.C. 6314(a)(2) and (3), related to 
representative use and test burden. (42 U.S.C. 6314(a)(4)(B))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including WSHPs, to 
determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
6314(a)(1)
    In addition, if the Secretary determines that a test procedure 
amendment is warranted, the Secretary must publish proposed test 
procedures in the Federal Register and afford interested persons an 
opportunity (of not less than 45 days' duration) to present oral and 
written data, views, and arguments on the proposed test procedures. (42 
U.S.C. 6314(b)) If DOE determines that test procedure revisions are not 
appropriate, DOE must publish in the Federal Register its determination 
not to amend the test procedures. (42 U.S.C. 6314(a)(1)(A)(ii))
    DOE undertook this rulemaking in satisfaction of the 7-year-
lookback obligations under EPCA. (42 U.S.C. 6314(a)(1)). As discussed 
previously in this document, WSHPs are a category of commercial package 
air conditioning and heating equipment. EPCA requires the DOE test 
procedures for commercial package air conditioning and heating

[[Page 84190]]

equipment to be the generally accepted industry testing procedure 
developed or recognized by AHRI or by ASHRAE, as referenced in ASHRAE 
90.1. (42 U.S.C. 6314(a)(4)(A)) EPCA further requires that each time 
the referenced industry test procedure is amended in ASHRAE 90.1, DOE 
must amend its test procedure to be consistent with the industry 
update, unless DOE determines in a rulemaking that there is clear and 
convincing evidence that the updated update industry test procedure 
would not be representative of an average use cycle or would be unduly 
burdensome to conduct. (42 U.S.C. 6314(a)(4)(B)(C)) However, under the 
7-year-lookback obligations, there is no ``clear and convincing 
evidence'' required in EPCA. Rather, EPCA only requires that DOE 
determine whether the amended test procedure would more accurately or 
fully comply with the requirements for the test procedure to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
6314(a)(1))
    DOE is publishing this final rule in satisfaction of its statutory 
obligations under EPCA. (42 U.S.C. 6314(a)(1)(A))

B. Background

    DOE's existing test procedure for WSHPs is specified at 10 CFR 
431.96 (``Uniform test method for the measurement of energy efficiency 
of commercial air conditioners and heat pumps''). The Federal test 
procedure currently incorporates by reference International 
Organization for Standardization (``ISO'') Standard 13256-1 (1998), 
``Water-source heat pumps--Testing and rating for performance--Part 1: 
Water-to-air and brine-to-air heat pumps,'' (``ISO 13256-1:1998'').
    DOE initially incorporated ISO 13256-1:1998 as the referenced test 
procedure for WSHPs on October 21, 2004 (69 FR 61962), and DOE last 
reviewed the test procedure for WSHPs as part of a final rule for 
commercial package air conditioners and heat pumps published in the 
Federal Register on May 16, 2012 (``May 2012 Final Rule''; 77 FR 
28928). In the May 2012 Final Rule, DOE retained the reference to ISO 
13256-1:1998 but adopted additional provisions for equipment setup at 
10 CFR 431.96(e), which provide specifications for addressing key 
information typically found in the installation and operation manuals. 
77 FR 28928, 28991.
    On June 22, 2018, DOE published a request for information (``RFI'') 
to collect information and data to consider amendments to DOE's test 
procedure for WSHPs (``June 2018 RFI''). 83 FR 29048.\4\ Subsequently, 
on August 30, 2022, DOE published a notice of proposed rulemaking 
(``NOPR'') in which DOE responded to stakeholders' comments on the June 
2018 RFI and proposed amendments to its test procedure for WSHPs 
(``August 2022 NOPR'') 87 FR 53302. In the August 2022 NOPR, DOE 
proposed to amend the test procedures for WSHPs to incorporate by 
reference AHRI Standard 340/360-2022 (I-P), ``2022 Standard for 
Performance Rating of Commercial and Industrial Unitary Air-
conditioning and Heat Pump Equipment'' (``AHRI 340/360-2022'') and 
ANSI/ASHRAE Standard 37-2009, ``Methods of Testing for Rating 
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment'' 
(``ANSI/ASHRAE 37-2009''). Id. at 87 FR 53348. Specifically, DOE 
proposed to implement these changes by adding new appendices C and C1 
to subpart F of part 431, both titled ``Uniform Test Method for 
Measuring the Energy Consumption of Water-Source Heat Pumps.'' 
(``appendix C'' and ``appendix C1,'' respectively). Id. at 87 FR 53351-
52252. The current DOE test procedure for WSHPs would be relocated to 
appendix C without change, and the new test procedure adopting AHRI 
340/360-2022 and ANSI/ASHRAE 37-2009 and any other amendments would be 
set forth in proposed appendix C1 for determining IEER. Id. at 87 FR 
53352-53353. DOE held a public meeting on September 14, 2022 (``NOPR 
public meeting'') to present the key proposals from the August 2022 
NOPR.
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    \4\ An extension of the comment period for the June 2018 RFI was 
published July 9, 2018. 83 FR 31704.
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    DOE received comments in response to the August 2022 NOPR from the 
interested parties listed in Table I.1.

           Table I.1--List of Commenters With Written Submissions in Response to the August 2022 NOPR
----------------------------------------------------------------------------------------------------------------
                                          Reference in this final     Comment No. in
              Commenter(s)                          rule                the docket           Commenter type
----------------------------------------------------------------------------------------------------------------
Air-Conditioning, Heating and            AHRI.....................                 24  Trade Association.
 Refrigeration Institute.
Appliance Standards Awareness Project,   Joint Commenters.........                 27  Efficiency Organizations.
 American Council for an Energy-
 Efficient Economy.
Northwest Energy Efficiency Alliance...  NEEA.....................                 25  Efficiency Organization.
New York State Energy Research and       NYSERDA..................                 21  State Agency.
 Development Authority.
ClimateMaster, Inc.....................  ClimateMaster............                 22  Manufacturer.
WaterFurnace International.............  WaterFurnace.............                 20  Manufacturer.
Enertech Global, LLC...................  Enertech.................                 19  Manufacturer.
Florida Heat Pump Manufacturing........  FHP......................                 26  Manufacturer.
The Geothermal Exchange Organization...  GeoExchange..............                 29  Trade Association.
Madison Indoor Air Quality.............  MIAQ.....................                 23  Manufacturer.
Trane Technologies.....................  Trane....................                 28  Manufacturer.
----------------------------------------------------------------------------------------------------------------

    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\5\ 
In addition to the comments listed in Table I.1, DOE also received 2 
comments from anonymous individuals, which were considered in the 
development of this final rule, but not cited individually. To the 
extent that interested parties have provided written comments that are 
substantively consistent with any oral comments provided during the 
NOPR public meeting, DOE cites the written comments throughout this 
final rule.

[[Page 84191]]

Any oral comments provided during the webinar that are not 
substantively addressed by written comments are summarized and cited 
separately throughout this final rule.
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    \5\ The parenthetical reference provides a reference for 
information located in the docket of DOE's rulemaking to develop an 
amended test procedure for WSHPs. (Docket No. EERE-2017-BT-TP-0029, 
which is maintained at www.regulations.gov). The references are 
arranged as follows: (commenter name, comment docket ID number, page 
of that document).
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    In May 2021, ISO published an updated version of Standard 13256-1, 
ISO Standard 13256-1 (2021), ``Water-source heat pumps--Testing and 
rating for performance--Part 1: Water-to-air and brine-to-air heat 
pumps,'' (``ISO 13256-1:2021''). In January 2023, ASHRAE published 
ASHRAE 90.1-2022. ASHRAE 90.1-2022 did not update the referenced test 
procedure for WSHPs.\6\
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    \6\ ASHRAE 90.1-2022 lists ANSI/AHRI/ASHRAE 13256-1: 1998 (2021) 
as the test procedure for WSHPs. However, DOE believes ASHRAE 
intended to include ``2012'' in the parentheses as that was the most 
recent year in which the 1998 version of 13256-1 was redesignated.
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    On September 11, 2023, AHRI published a new industry test standard 
for WSHPs, titled AHRI Standard 600, ``Standard for Performance Rating 
of Water/Brine to Air Heat Pump Equipment'' (``AHRI 600-2023''). DOE 
worked with stakeholders (including WSHP manufacturers and efficiency 
advocates) as part of the AHRI Geothermal and WSHP standards technical 
committee (``STC'') to develop AHRI 600-2023, which addresses many of 
the issues in the current WSHP test procedure that DOE raised in the 
August 2022 NOPR. The intent of the Geothermal and WSHP STC was for 
AHRI 600-2023 to be used for testing WSHPs instead of any versions of 
ISO Standards 13256-1.

II. Synopsis of the Final Rule

    In this final rule DOE is establishing new appendices C and C1 to 
subpart F of part 431. The current DOE test procedure for WSHPs is 
relocated to appendix C without change. The amended test procedure for 
WSHPs is established in a new appendix C1, which includes the following 
amended test procedure requirements for WSHPs for measuring the updated 
efficiency metrics: (1) integrated energy efficiency ratio (``IEER'') 
for WSHPs using AHRI 600-2023; and (2) applied coefficient of 
performance (``ACOP'') using AHRI 600-2023. Use of the amended test 
procedure in appendix C1 will not be required until such time as 
compliance is required with amended energy conservation standards for 
WSHPs denominated in terms of IEER, should DOE adopt such standards.
    Additionally, DOE is expanding the scope of the test procedure to 
include WSHPs with capacities between 135,000 and 760,000 British 
thermal units per hour (``Btu/h''), as well as specifying the 
components that must be present for testing and amending certain 
provisions related to representations and enforcement in 10 CFR part 
429.
    As discussed in this final rule, DOE has concluded that the amended 
test procedure in appendix C1 (incorporating by reference the most 
recent industry consensus test standard for WSHPs, AHRI 600-2023) 
provides more representative results and more fully complies with the 
requirements of 42 U.S.C. 6314(a)(2) than testing with the current 
Federal test procedure (based on ISO 13256-1:1998).
    The adopted amendments are summarized in Table II.1 and compared to 
the test procedure provisions in place prior to the amendment, as well 
as the reason for the adopted change.

      Table II.1--Summary of Changes in the Amended Test Procedure
------------------------------------------------------------------------
                                     Amended test
   Current DOE test procedure          procedure          Attribution
------------------------------------------------------------------------
Located in 10 CFR 431.96........  Current test        Readability of
                                   procedure moved     test procedure.
                                   to appendix C to
                                   10 CFR 431.96 and
                                   amended test
                                   procedure
                                   established in
                                   appendix C1 to 10
                                   CFR 431.96.
Scope is limited to units with a  Expands the scope   Harmonize with
 cooling capacity less than        of the test         scope of test
 135,000 Btu/h.                    procedure to        procedure for
                                   additionally        water-cooled
                                   include units       commercial
                                   with a cooling      unitary air
                                   capacity greater    conditioners.
                                   than or equal to
                                   135,000 Btu/h and
                                   less than 760,000
                                   Btu/h in 10 CFR
                                   431.96.
Incorporates by reference ISO     Incorporates by     Improve
 13256-1:1998.                     reference AHRI      representativenes
                                   600-2023 into       s of test
                                   appendix C1.        procedure.
Includes provisions for           Includes            Improve
 determining EER metric.           provisions for      representativenes
                                   determining IEER    s of test
                                   by incorporating    procedure.
                                   by reference AHRI
                                   600-2023 into
                                   appendix C1.
Specifies test condition of 68    Changes the test    Improve
 [deg]F for measuring              condition for       representativenes
 coefficient of performance        ACOP to 50          s of test
 (``COP'').                        [deg]F, by          procedure.
                                   incorporating by
                                   reference AHRI
                                   600-2023 into
                                   appendix C1.
Does not include WSHP-specific    Includes            Establish WSHP-
 provisions for determination of   provisions in 10    specific
 represented values in 10 CFR      CFR 429.43          provisions for
 429.43.                           specific to WSHPs   determination of
                                   for determining     represented
                                   represented         values.
                                   values.
Does not include WSHP-specific    Adopts product-     Establish
 enforcement provisions in 10      specific            enforcement
 CFR 429.134.                      enforcement         provisions for
                                   provisions for      DOE testing of
                                   WSHPs regarding     WSHPs.
                                   verification of
                                   cooling capacity,
                                   testing of
                                   systems with
                                   specific
                                   components, and
                                   IEER testing
                                   conducted by DOE.
------------------------------------------------------------------------

    DOE has determined that the test procedure in appendix C, as 
described in section III of this final rule regarding the establishment 
of appendix C, does not alter the measured efficiency of WSHPs or 
require retesting solely as a result of the establishment of appendix 
C. Additionally, DOE has determined that the establishment of appendix 
C will not increase the cost of testing.
    DOE has determined that the amended test procedure adopted in 
appendix C1 does alter the measured efficiency of WSHPs and would 
increase the cost of testing relative to the current Federal test 
procedure, as discussed further in section III.I of this document. 
However, as stated, use of appendix C1 will not be required until the 
compliance date of any amended standards denominated in terms of IEER, 
should DOE adopt such standards. DOE has also determined that the 
amended test procedure will not be unduly burdensome to conduct.
    For units with cooling capacity greater than or equal to 135,000 
Btu/h and less than 760,000 Btu/h newly added within scope of the WSHP 
test procedure, testing according to the established test procedure for 
purposes of certifications of compliance will not

[[Page 84192]]

be required until the compliance date of any energy conservation 
standards for such equipment, should DOE adopt such standards. However, 
if a manufacturer chooses to make representations of the energy 
efficiency or energy use of such equipment, beginning 360 days after 
publication of the final rule in the Federal Register, the manufacturer 
will be required to base such representations on the DOE test 
procedure. (42 U.S.C. 6314(d)(1))
    The effective date for the amended test procedure adopted in this 
final rule is 30 days after publication of this document in the Federal 
Register. Discussion of DOE's actions are addressed in detail in 
section III of this document.

III. Discussion

A. Scope of Applicability

    This rulemaking applies to WSHPs, which are a category of small, 
large, and very large commercial package air-conditioning and heating 
equipment. (See 42 U.S.C. 6311(1)(B)-(D)) In its regulations, DOE 
defines WSHP as ``a single-phase or three-phase reverse-cycle heat pump 
that uses a circulating water loop as the heat source for heating and 
as the heat sink for cooling. The main components are a compressor, 
refrigerant-to-water heat exchanger, refrigerant-to-air heat exchanger, 
refrigerant expansion devices, refrigerant reversing valve, and indoor 
fan. Such equipment includes, but is not limited to, water-to-air 
water-loop heat pumps.'' 10 CFR 431.92.
1. WSHPs With a Cooling Capacity Greater Than or Equal to 135,000 Btu/h
    The current Federal WSHP test procedure and energy conservation 
standards apply to WSHPs with a rated cooling capacity below 135,000 
Btu/h. 10 CFR 431.96, Table 1 and 10 CFR 431.97, Table 3. In the August 
2022 NOPR, DOE proposed to expand the scope of applicability of the 
test procedure to include WSHPs with a cooling capacity between 135,000 
and 760,000 Btu/h. 87 FR 53302, 53307. Specifically, DOE proposed to 
update Table 1 to 10 CFR 431.96 to include WSHPs with a cooling 
capacity greater than or equal to 135,000 Btu/h and less than 240,000 
Btu/h under Large Commercial Package Air-Conditioning and Heating 
Equipment; and to include WSHPs with a cooling capacity greater than or 
equal to 240,000 Btu/h and less than 760,000 Btu/h under Very Large 
Commercial Package Air-Conditioning and Heating Equipment. Id. In the 
August 2022 NOPR, DOE tentatively determined that, based on the 
presence on the market of units over 135,000 Btu/h with efficiency 
ratings and the identification of laboratories capable of testing such 
units, such testing would not be unduly burdensome. Id. at 87 FR 53306. 
Additionally, DOE stated that expanding the scope of DOE's test 
procedure for WSHPs to include equipment with a cooling capacity 
between 135,000 Btu/h and 760,000 Btu/h would ensure that 
representations for all WSHPs are made using the same test procedure 
and that ratings for equipment in this cooling capacity range are 
appropriately representative. Id. at 87 FR 53306-53307. DOE requested 
comments on the proposed expansion of the scope of applicability of the 
Federal test procedure to include WSHPs with a cooling capacity between 
135,000 and 760,000 Btu/h. Id. at 87 FR 53307.
    In response to the June 2022 NOPR, some commenters expressed 
concern with the proposal to expand the scope of the test procedure. 
AHRI commented that it is concerned with DOE's proposal to expand 
testing coverage and update test procedures without taking steps to 
measure the impact on manufacturers and third-party test labs. (AHRI, 
No. 24 at pp. 2-3) AHRI asserted that the August 2022 NOPR does not 
show evidence of DOE's participation in the critical consensus process 
required for developing test procedures and improving efficiency for 
ASHRAE 90.1, which involves conversations regarding lab capabilities, 
product availability, and product efficiencies. (Id.)
    AHRI further commented that the impact on manufacturers of DOE's 
proposed test coverage expansion has not been quantified. (Id. at p. 3) 
AHRI stated that it expects third-party test labs will not be able to 
accommodate the expanded scope to include equipment up to 760,000 Btu/
h, as such an expansion of scope would require test labs to increase 
their testing capacity from 3 gallons per minute (``GPM'') per ton 
(``GPM/ton'') at 50 [deg]F to nearly 200 GPM. (Id.) AHRI commented that 
the additional constraints placed on test labs would cause delays in 
testing other equipment as well as WSHPs. (Id.)
    Similarly, ClimateMaster opposed DOE's proposal to include WSHP 
equipment with capacities greater than 135,000 Btu/h within the scope 
of the test procedure due to the cost burden that ClimateMaster 
asserted would be imposed on manufacturers and consumers. 
(ClimateMaster, No. 22 at p. 2) ClimateMaster stated that these larger 
model sizes account for only 0.4 percent of its overall market volume 
from 2019 to 2021. (Id.) ClimateMaster presented data showing that 
adding the higher-capacity models to the scope of the test procedure 
would increase the certification cost by $184,000 per year to 
accommodate testing and equipment costs. (Id.) ClimateMaster further 
commented that third-party compliance labs are unable to test equipment 
above 420,000 Btu/h, which would render DOE's proposal to test WSHPs 
that reach 760,000 Btu/h impossible. (Id.) ClimateMaster noted that the 
increased cost burden needed to accommodate such a small percentage of 
affected equipment would negatively affect consumers as well as 
manufacturers. (Id.) ClimateMaster recommended that DOE maintain the 
scope of applicability of the Federal test procedure to only include 
WSHPs with cooling capacity below 135,000 Btu/h. (Id. at p. 3)
    FHP commented that its main concern regarding DOE's proposal to 
expand the scope of applicability is lab availability. (FHP, No. 26 at 
p. 2) FHP stated that it has found only a limited supply of WSHP 
testing facilities, none of which have a capacity to test equipment 
over 480,000 Btu/h. (Id.) FHP recommended that DOE provide a list of 
testing facilities for WSHPs with a cooling capacity greater than 
135,000 Btu/h, stating that multiple testing facilities must be 
available to ensure that an increased demand for large unit testing 
does not also cause spikes in testing costs due to supply and demand 
pressures. (Id.) FHP further commented that WSHPs with capacities above 
135,000 Btu/h account for less than 1 percent of the market share. 
(Id.)
    MIAQ commented that it is concerned DOE has not quantified the 
impact on manufacturers and third-party labs of expanding the scope of 
coverage to larger equipment. (MIAQ, No. 23 at p. 3) MIAQ stated that 
conversations regarding lab capabilities and product availability and 
efficiency occur during the consensus process required for developing 
test procedures in ASHRAE 90.1. (Id.) MIAQ stated that the water volume 
required for testing larger capacities up to 760,000 Btu/h may limit 
testing. (Id.) More specifically, MIAQ stated that testing a 760,000 
Btu/h WSHP would require approximately 200 GPM of 50 [deg]F water, 
which MIAQ stated would require large chillers to maintain the water at 
the correct temperature. (Id.) MIAQ also noted that due to the 
increased need for larger spaces capable of testing such equipment, 
there could be bottlenecks at third-party test labs, which also test 
other categories of commercial package air conditioning and heating 
equipment. (Id.)

[[Page 84193]]

    WaterFurnace stated that there are no known WSHP products with a 
cooling capacity above approximately 360,000 Btu/h nor any test 
facilities capable of testing such WSHPs at the required conditions for 
IEER. (WaterFurnace, No. 20 at p. 6) WaterFurnace commented that DOE 
did not justify regulating this larger equipment and that doing so 
would be a burden on the industry and testing facilities. (Id.)
    Other commenters supported the proposal to expand the scope of the 
WSHP test procedure. The Joint Commenters, NEEA, and NYSERDA supported 
DOE's proposal to include WSHPs with cooling capacities between 135,000 
and 760,000 Btu/h in the scope of the test procedure. (Joint 
Commenters, No. 27 at p. 1; NEEA, No. 25 at p. 2; NYSERDA, No. 21 at p. 
2) The Joint Commenters stated that they believe it is important that 
equipment in this capacity range be testing using a standardized test 
procedure and that expanding the scope of the test procedure would 
bring it into alignment with test procedures for other commercial 
package air-conditioning and heating equipment. (Joint Commenters, No. 
27 at p. 1)
    NEEA commented that, while this size range may account for 
relatively few annual sales, expanding the test procedure to larger 
capacity equipment would ensure that large equipment is fairly rated 
and regulated and held to the same standards as smaller equipment of 
the same type. (NEEA, No. 25 at p. 2)
    NYSERDA asserted that expanding the scope is a feasible and 
necessary change to ensure that WSHPs of varying sizes are consistently 
tested according to industry standards, which will demonstrate to 
customers that WSHPs--especially geothermal WSHPs--are reliable and 
thus enable WSHP market growth. (NYSERDA, No. 21 at p. 2)
    As discussed in the August 2022 NOPR, DOE has identified numerous 
model lines of WSHPs with a cooling capacity over 135,000 Btu/h from a 
wide variety of manufacturers. 87 FR 53302, 53306. The manufacturer 
literature for all identified model lines includes efficiency 
representations that are explicitly based on ISO 13256-1:1998, the 
current industry standard, indicating efficiency representations can be 
made for these models using an industry consensus test procedure for 
WSHPs. Id.
    In response to comments from AHRI, Climate Master, and 
WaterFurnace, as discussed in the August 2022 NOPR, DOE is aware of 
several independent test labs that have the capability to test WSHPs 
with a cooling capacity over 135,000 Btu/h. Id. DOE conducted 
investigative testing on multiple WSHP models with a cooling capacity 
over 135,000 Btu/h at one such independent test lab and did not 
encounter any difficulties specific to units in this capacity range. 
Id. Regarding comments by ClimateMaster and FHP stating that test labs 
cannot test units greater than 420,000 Btu/h and 480,000 Btu/h, 
respectively, comments submitted by WaterFurnace indicate that the 
largest models currently available on the market are 360,000 Btu/h, 
which DOE research corroborates. As such, any capacity limitations for 
testing as asserted by ClimateMaster and FHP would not impact any 
models currently on the market.
    Further, DOE notes that AHRI 600-2023 includes provisions for 
testing units with capacities over 135,000 Btu/h. Both ASHRAE 90.1 and 
DOE regulations cover other categories of commercial air conditioning 
and heating equipment, including water-cooled commercial unitary air 
conditioners (``WCUACs''), with a cooling capacity up to 760,000 Btu/h. 
As discussed in the August 2022 NOPR, DOE has determined that testing 
WSHPs with a cooling capacity over 135,000 Btu/h would be of comparable 
burden to testing other commercial air conditioning and heating 
equipment of similar capacity, such as WCUACs. Id.
    Regarding comments on the potential burden of testing such units, 
EPCA does not require DOE to consider only burden-reducing options, but 
rather requires only that the test procedure must not be unduly 
burdensome to conduct. Expanding the scope of the test procedure to 
include larger equipment would not necessitate certification unless DOE 
were to establish standards for such equipment. Until such a time, an 
expansion of scope for the test procedure would require only that if 
manufacturers choose to make optional representations of efficiency for 
WSHPs with a cooling capacity over 135,000 Btu/h, that such optional 
representations be made in accordance with the DOE test procedure. 
Further, DOE notes that representations for WSHPs can be made either 
based on testing (in accordance with 10 CFR 429.43(a)(1)) or based on 
alternative efficiency determination methods (``AEDMs'') (in accordance 
with 10 CFR 429.43(a)(2)). An AEDM is a computer modeling or 
mathematical tool that predicts the performance of non-tested basic 
models. These computer modeling and mathematical tools, when properly 
developed, can provide a means to predict the energy usage or 
efficiency characteristics of a basic model of a given covered product 
or equipment and reduce the burden and cost associated with testing. 
Whereas DOE requires at least two units to be tested per basic model 
when represented values are determined through testing, DOE requires 
each AEDM to be validated by tests of only two WSHP basic models of any 
capacity (in accordance with 10 CFR 429.70(c)(2)). Based on DOE's 
observation of the prevalence of use of AEDMs for WSHP and similar 
equipment for which energy conservation standards currently apply 
(i.e., for equipment with a cooling capacity no greater than 135,000 
Btu/h), DOE expects that representations of efficiency could be 
determined through the use of AEDMs for the majority of models with a 
cooling capacity over 135,000 Btu/h. As such, DOE expects an expansion 
of scope for the DOE test procedure to include equipment with a cooling 
capacity over 135,000 Btu/h would not necessitate the testing of many 
such larger units. Therefore, testing would not be as burdensome as 
noted by commenters.
    Based on the presence on the market of units over 135,000 Btu/h, 
the identification of laboratories capable of testing such units, DOE's 
observation that representations of efficiency for such equipment are 
currently being made, and the inclusion of units over 135,000 Btu/h 
within the scope of the most recent industry consensus test standard 
for WSHPs (AHRI 600-2023), DOE has determined that testing units with a 
cooling capacity over 135,000 Btu/h is feasible and would not be unduly 
burdensome. As discussed, expanding the scope of DOE's test procedure 
for WSHPs to include equipment with a cooling capacity between 135,000 
Btu/h and 760,000 Btu/h would ensure that representations for all WSHPs 
are made using the same test procedure and that ratings for equipment 
in this cooling capacity range are appropriately representative.
    For the reasons discussed in the proceeding paragraphs and in the 
August 2022 NOPR, DOE is expanding the scope of applicability of the 
WSHP test procedure to include WSHPs with a cooling capacity between 
135,000 and 760,000 Btu/h consistent with the scope of AHRI 600-2023. 
Specifically, DOE is updating Table 1 to 10 CFR 431.96 to include WSHPs 
with a cooling capacity greater than or equal to 135,000 Btu/h and less 
than 240,000 Btu/h under Large Commercial Package Air-Conditioning and 
Heating Equipment and to include WSHPs with a cooling capacity greater 
than or equal to 240,000 Btu/h and less than 760,000 Btu/h under Very 
Large

[[Page 84194]]

Commercial Package Air-Conditioning and Heating Equipment.
    As previously discussed, DOE does not currently specify energy 
conservation standards for WSHPs with a cooling capacity over 135,000 
Btu/h. DOE would consider any future standards applicable to WSHPs over 
135,000 Btu/h in a separate energy conservation standards rulemaking. 
Manufacturers of WSHPs with a cooling capacity over 135,000 Btu/h would 
not be required to test WSHPs with a cooling capacity over 135,000 Btu/
h until such time as compliance with standards for this equipment were 
required, should DOE adopt such standards. DOE notes, however, that 
beginning 360 days after this final rule publishes in the Federal 
Register, any voluntary representations with respect to energy use or 
efficiency must be based on the test procedure in appendix C, and any 
voluntary representations of IEER or ACOP must be based on the test 
procedure in appendix C1.
2. Representations for Residential Applications
    Sections 6.5 and 6.6 of AHRI 600-2023 state that provisions for 
determination of residential cooling capacity and efficiency are to be 
added in a future revision. In the August 2022 NOPR, DOE proposed to 
allow optional energy efficiency ratio (``EER'') and COP 
representations at the full-load and part-load EWT conditions specified 
in Table 1 of ISO 13256-1:1998 per the DOE test procedure proposed in 
appendix C1. 87 FR 53302, 53313. DOE notes that the residential 
representations discussed in AHRI 600-2023 are separate from the 
proposed optional representations from the August 2022 NOPR, as test 
provisions in AHRI 600-2023 specify separate air and liquid external 
static pressures to be used during testing to develop ratings for 
residential applications. However, the residential representations have 
not yet been fully developed for WSHPs, as indicated in sections 6.5 
and 6.6 of AHRI 600-2023. Therefore, DOE is not adding any provisions 
regarding residential representations in this final rule but will 
continue to work with the AHRI 600 committee to develop such 
provisions.

B. Definition

    As discussed, WSHPs are a category of commercial package air-
conditioning and heating equipment. The current definition for ``water-
source heat pump'' does not explicitly state that it is ``commercial 
package air-conditioning and heating equipment.'' This is inconsistent 
with the definitions of most other categories of commercial package 
air-conditioning and heating equipment (e.g., computer room air 
conditioner, single package vertical air conditioner, variable 
refrigerant flow multi-split air conditioner). See 10 CFR 431.92.
    To provide consistency with other definitions of specific 
categories of commercial package air-conditioning and heating 
equipment, DOE proposed in the August 2022 NOPR to amend the definition 
of ``water-source heat pump'' to explicitly indicate that WSHPs are a 
category of commercial package air-conditioning and heating equipment. 
87 FR 53302, 53307. This proposed clarification to the ``water-source 
heat pump'' definition would not change the scope of equipment covered 
by the definition.
    In addition, the current definition for WSHPs lists the main 
components of a WSHP and it includes ``indoor fan'' on that list. See 
10 CFR 431.92. DOE discussed in the August 2022 NOPR that it has 
identified coil-only WSHPs on the market that rely on a separately 
installed furnace or modular blower for indoor air movement. 87 FR 
53302, 53307. To clarify that coil-only WSHPs are covered under the 
WSHP definition, DOE proposed to amend the WSHP definition to make 
clear that an indoor fan is not an included component for coil-only 
WSHPs. Id. Specifically, DOE proposed to include the parenthesized 
statement ``except that coil-only units do not include an indoor fan'' 
in the sentence listing the main components in the proposed WSHP 
definition. Id.
    DOE requested comment on the proposed change to the definition of 
WSHP to explicitly indicate that WSHP is a category of commercial 
package air-conditioning and heating equipment and to clarify that the 
presence of an indoor fan does not apply to coil-only units. Id.
    ClimateMaster generally agreed with DOE's proposed definition of 
WSHP, but requested clarity on what constitutes a commercial system. 
(ClimateMaster, No. 22 at p. 3) ClimateMaster commented that other 
industry test programs clearly demarcate the difference between systems 
through listed capacity. (Id.) ClimateMaster noted that the current 
definition includes only packaged systems but that DOE's proposed 
amendments in the August 2022 NOPR specified procedures for testing 
split systems. (Id.) ClimateMaster stated that it is not able to 
determine with the current definition what exact products would fall 
under the certification program and how DOE would enforce which 
products are covered by the applicable standards. (Id.) ClimateMaster 
also stated that there were non-reversible WSHP products that operate 
as either cooling only units or utilize a hydronic coil that are not 
covered by the current definition. ClimateMaster stated that provisions 
should be made for this equipment type. (Id.)
    WaterFurnace questioned whether it would be necessary to change the 
definition of WSHP if DOE were to maintain the method of test based on 
ISO 13256 and AHRI 600. (WaterFurnace, No. 20 at p. 6) WaterFurnace 
recommended using the term ``heat pump'' in lieu of ``air conditioner 
and heating equipment,'' which WaterFurnace asserted is technically 
inaccurate. (Id.)
    Regarding ClimateMaster's request for clarity regarding the 
definition, DOE notes that all products that meet the WSHP definition, 
with sizes less than 760,000 Btu/h cooling capacity (see discussion in 
section III.A of this final rule), would be considered a WSHP, 
regardless of whether the models are marketed and distributed in 
commerce for commercial or residential applications. The definition of 
WSHPs includes both single-package and split-system equipment.
    Regarding WaterFurnace's comment on whether it would be necessary 
to change the definition of WSHP if DOE were to maintain the method of 
test based on ISO 13256 and AHRI 600, the DOE definition of WSHP serves 
to specify models that are within the scope of coverage of DOE's 
regulations and is independent of the test procedure being used for 
WSHPs. DOE also notes in response to WaterFurnace's comment that the 
definition of WSHP already uses the term ``heat pump'' to define WSHP 
and that the term ``commercial package air-conditioning and heating 
equipment'' is being added to the definition only to indicate the 
larger type of equipment, as defined in the EPCA, of which WSHPs are a 
category.
    Regarding ClimateMaster's comment that the current definition does 
not cover units that are not reversible, DOE considers water-source 
heat pumps to include only models with reverse-cycle heating; 
therefore, DOE is not removing the ``reverse-cycle'' provision from the 
WSHP definition.
    For the reasons discussed, DOE is adopting an amended definition of 
WSHP that is identical to the definition proposed in the August 2022 
NOPR, as follows:
    Water-source heat pump means commercial package air-conditioning 
and heating equipment that is a single-phase or three-phase reverse-
cycle heat pump that uses a circulating water loop as the heat source 
for heating and as the

[[Page 84195]]

heat sink for cooling. The main components are a compressor, 
refrigerant-to-water heat exchanger, refrigerant-to-air heat exchanger, 
refrigerant expansion devices, refrigerant reversing valve, and indoor 
fan (except that coil-only units do not include an indoor fan). Such 
equipment includes, but is not limited to, water-to-air water-loop heat 
pumps.

C. Organization of the Amended DOE Test Procedures

    In this final rule, DOE is relocating and centralizing the current 
test procedure for WSHPs to a new appendix C to subpart F of part 431 
and establishing an amended test procedure for WSHPs in a new appendix 
C1 to subpart F of part 431. Appendix C maintains the substance of the 
current test procedure and continues to reference ISO 13256-1:1998 and 
provide for determining EER and COP. Appendix C also includes the 
additional test provisions for equipment set-up currently codified at 
10 CFR 431.96(e). As discussed, WSHPs are required to be tested 
according to appendix C until such time as compliance is required with 
an amended energy conservation standard based on the amended test 
procedure in appendix C1, should DOE adopt such a standard.
    DOE is also establishing an amended test procedure for WSHPs in a 
new appendix C1 to subpart F of part 431 that includes provisions for 
determining IEER and ACOP by incorporating by reference AHRI 600-2023, 
as discussed further throughout this document. WSHPs are not required 
to be tested according to appendix C1 until such time as compliance is 
required with an amended energy conservation standard denominated in 
terms of the IEER metric, should DOE adopt such a standard; although, 
any voluntary representations of IEER prior to the compliance date of 
any such standard must be based on testing according to appendix C1.

D. Updates to Industry Standards

    As noted in section I.B. of this document, the DOE test procedure 
currently incorporates by reference ISO 13256-1:1998 and includes 
additional provisions for equipment set-up at 10 CFR 431.96(e), which 
provide specifications for addressing key information typically found 
in the installation and operation manuals. In the August 2022 NOPR, DOE 
proposed to adopt an amended test procedure for WSHPs in a new appendix 
C1 that would incorporate by reference AHRI 340/360-2022 for measuring 
efficiency using IEER. 87 FR 53302, 53311. Because AHRI 340/360-2022 
references ANSI/ASHRAE 37-2009 for test provisions, DOE also proposed 
to incorporate by reference relevant sections of ANSI/ASHRAE 37-2009 in 
its amended test procedure for WSHPs. Id. at 87 FR 53312. Compared to 
the current test procedure, the key substantive changes that would 
result from DOE adopting the proposed test procedure included the 
following:
    (1) A new energy efficiency descriptor, IEER, which incorporates 
part-load cooling performance;
    (2) Modified test conditions for determining COP;
    (3) Minimum external static pressure (``ESP'') requirements, 
instructions for setting airflow and ESP, and tolerances for airflow 
and ESP, and
    (4) Specified liquid ESP requirements for units with integral pumps 
and a method to account for total pumping effect for units without 
integral pumps. Id. at 87 FR 53305.
    In response to this proposal, DOE received multiple comments 
(summarized in the following sub-sections) urging DOE not to 
incorporate by reference AHRI 340/360-2022 as the test procedure for 
WSHPs, to continue to collaborate with industry on finalizing AHRI 600, 
and to instead adopt the revised industry test standard resulting from 
work on AHRI 600. As previously noted, after publication of the August 
2022 NOPR, DOE worked with the AHRI Geothermal and WSHP STC to develop 
a revised version of AHRI 600 (AHRI 600-2023) to address the issues DOE 
raised in the August 2022 NOPR. As discussed further throughout this 
section, AHRI 600-2023 includes a method to determine IEER for WSHPs 
similar to that proposed in the August 2022 NOPR and addresses many of 
the concerns expressed by commenters in response to the August 2022 
NOPR. As discussed, AHRI 600-2023 is intended to serve as the primary 
industry test procedure for WSHPs going forward and it does not 
reference any versions of ISO Standard 13256-1. Instead, AHRI 600-2023 
references ANSI/ASHRAE 37-2009 and includes sufficient provisions for 
testing WSHPs that references to test provisions in ISO Standard 13256-
1 or AHRI 340/360-2022 are not needed.
    As discussed further throughout this section, in this final rule, 
DOE is adopting an amended test procedure that incorporates by 
reference AHRI 600-2023, with minor differences as explained further 
throughout the following sections of this document.
    In the following sections, DOE summarizes comments received in 
response to the August 2022 NOPR with regard to industry standards.
1. Comments Regarding DOE's Authority
    As discussed previously in this document, with respect to small, 
large, and very large commercial package air conditioning and heating 
equipment (of which WSHPs are a category), EPCA directs that when the 
generally accepted industry testing procedures or rating procedures 
developed or recognized by AHRI or by ASHRAE, as referenced in ASHRAE 
90.1, are amended, the Secretary shall amend the DOE test procedure 
consistent with the amended industry test procedure or rating procedure 
unless the Secretary determines, by clear and convincing evidence, that 
to do so would not meet the requirements for test procedures to produce 
results representative of an average use cycle and is not unduly 
burdensome to conduct. (42 U.S.C. 6314(a)(4)(A)-(B))
    In response to the August 2022 NOPR, AHRI, MIAQ, and WaterFurnace 
expressed concern with DOE's proposal to adopt a test procedure 
different from the industry standard (i.e., ISO 13256-1:1998 and the 
not yet published AHRI 600 standard), and the procedure cited in ASHRAE 
90.1. (AHRI, No. 24 at pp. 1-2; MIAQ, No. 23 at pp. 1-2; WaterFurnace, 
No. 20 at p. 1) AHRI, MIAQ, and WaterFurnace noted that EPCA explicitly 
directs DOE to adopt the industry consensus test procedure cited in 
ASHRAE 90.1 and asserted that EPCA precludes DOE from adopting as a 
national standard a wholly different test procedure from that cited in 
ASHRAE 90.1. (Id.) These commenters urged DOE to adopt a revised test 
method only after it has been published by AHRI and adopted by ASHRAE 
in ASHRAE 90.1. (Id.)
    MIAQ asserted further that EPCA requires DOE to justify by clear 
and convincing evidence each amendment or difference between AHRI 340/
360-2022 and ISO 13256-1:1998. (MIAQ, No. 23 at p. 2) MIAQ commented 
that DOE has determined in past rulemakings that ISO 13256-1 is cost 
effective and representative of energy use. (Id.) MIAQ stated that any 
deviation from ASHRAE 90.1 requires quantification of the burden and 
that only modifications that reduce testing burden on manufacturers can 
be considered. (Id. at p. 3)
    AHRI and MIAQ commented that DOE and outside stakeholders have been 
developing a consensus-based revision to the test procedure for 
commercial packaged air conditioners and heat pumps (``CUAC/HPs''). 
(AHRI,

[[Page 84196]]

No. 24 at p. 2; MIAQ, No. 23 at p. 2) AHRI and MIAQ further stated that 
after AHRI 600 has been finalized and adopted, AHRI will introduce the 
new test procedure to ASHRAE 90.1 to begin the procedural process for 
updates. (AHRI, No. 24 at p. 3; MIAQ, No. 23 at p. 2) AHRI and MIAQ 
commented that waiting to harmonize standards would establish 
consistent energy efficiency levels and design requirements between 
industry and Federal requirements, as well as comparable metrics and 
scope. (AHRI, No. 24 at p. 3; MIAQ, No. 23 at pp. 2-3) AHRI and MIAQ 
recommended that DOE continue to work with AHRI and other stakeholders 
to finalize AHRI 600 and support a proposed amendment to ASHRAE 90.1, 
which DOE could adopt as the national test procedure during the next 
rulemaking. (AHRI, No. 24 at p. 4; MIAQ, No. 23 at pp. 3, 9)
    ClimateMaster commented that DOE has not followed a cooperative 
approach to improve the test methods as proposed in the August 2022 
NOPR. (ClimateMaster, No. 22 at p. 1) ClimateMaster asserted that this 
seems to violate EPCA, which requires DOE to adopt the test procedure 
cited in ASHRAE 90.1. (Id.)
    With regard to comments asserting that DOE does not have the 
authority to adopt a test procedure prior to its inclusion in ASHRAE 
90.1, EPCA provides DOE with authority to adopt an amended test 
procedure in satisfaction of EPCA's 7-year-lookback review requirement 
for test procedures. (42 U.S.C. 6314(a)(1)(A)). Under its 7-year-
lookback review, DOE must ensure that test procedures established are 
reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs during a 
representative average use cycle and are not unduly burdensome to 
conduct. (42 U.S.C. 6314(a)(2)) During its 7-year lookback review, DOE 
is directed by EPCA to evaluate whether an amended test procedure would 
more accurately or fully comply with those requirements, and if DOE 
determines an amended test procedure would do so, then DOE is required 
to prescribe such test procedures for the equipment class. (42 U.S.C. 
6314(a)(1)(A)) It is important to note that under the 7-year lookback 
DOE does not need clear and convincing evidence that an amended test 
procedure would more accurately or fully comply with EPCA's 
requirements. (Id.) Rather, DOE must show that the amended test 
procedure is reasonably designed to produce test results which reflect 
energy efficiency, energy use, and estimated operating costs during a 
representative average use cycle and are not unduly burdensome to 
conduct. (42 U.S.C. 6314(a)(2)) For example, a test procedure 
referenced by ASHRAE 90.1 may not be reasonably representative because 
more representative test procedures are available. And a test procedure 
that was reasonably representative in the past may become unreasonably 
representative when newly available test procedures allow for better, 
more complete measurements. DOE's 7-year-lookback review under EPCA 
ensures that DOE is not bound to an industry test procedure that has 
not been updated and is no longer representative of current equipment.
    DOE notes that submitted comments from AHRI, WaterFurnace, 
ClimateMaster, and MIAQ do not mention DOE's 7-year-lookback review and 
therefore only engaged with the review process under 42 U.S.C. 
6314(a)(4)(A). AHRI stated in its written comment that DOE is mandated 
to adopt an industry test procedure only after that test procedure is 
adopted in ASHRAE 90.1 but identified no such mandate within the 
statute itself. It is important to note that the 7-year-lookback review 
language at issue here was added to EPCA in EISA 2007, well after the 
relevant ASHRAE 90.1 test procedure language was added in 1992. 
(Compare Sec. 302 of EISA 2007, Pub. L. 110-140, 121 STAT. 1552 (Dec. 
19, 2007) with Sec. 121 of the Energy Policy Act of 1992, Pub. L. 106-
486, 106 STAT. 2808 (Oct. 24, 1992)). Therefore, the most natural 
reading of the two provisions together is that Congress intended to add 
the 7-year-lookback review to those triggers for review of test 
procedures that already existed. The language of the 7-year-lookback 
review applies generally to all covered equipment. Rather than restrict 
DOE to an outdated test procedure in the manner the industry commenters 
suggest, EPCA instead compels DOE to use due diligence to review the 
totality of relevant and available information before settling on 
appropriate energy conservation standards and test procedures.
    As a result, it is appropriate for DOE to consider in its 7-year-
lookback whether amendments to the test procedure would more accurately 
produce test results which reflect energy efficiency, energy use, and 
estimated operating costs during a representative average use cycle and 
would not be unduly burdensome to conduct even without an update to 
AHSRAE 90-1. DOE finds here that the test procedure provided in the 
updated industry consensus test standard for WSHPs (AHRI 600-2023), and 
therefore the test procedure specified in the regulatory text of this 
final rule, is more representative without incurring undue burden, as 
discussed below, thereby satisfying EPCA's requirements.
    DOE acknowledges that DOE has previously stated that it will only 
consider an update to ASHRAE 90.1 that modifies the referenced industry 
test procedure to be a trigger under that provision of the statute, as 
opposed to an update of just the industry test procedure itself. (See 
e.g., 86 FR 35668, 35676 (July 7, 2021)). DOE stands by that position 
regarding what constitutes a triggering event in the context of ASHRAE 
equipment and does not consider the provisions in 42 U.S.C. 6314(a)(4) 
to have been triggered. However, that does not preclude DOE from 
considering an amended test procedure when reviewing DOE's test 
procedures under EPCA's 7-year-lookback provision. Not only does DOE 
have discretion to do so, but it has a statutory duty to do so, to 
ensure that its test procedures produce results that are representative 
of an average use cycle and are not unduly burdensome to conduct.
    DOE has determined that the test procedure adopted in this final 
rule for WSHPs would improve the representativeness of the current 
Federal test procedure for WSHPs and would not be unduly burdensome. 
Specifically, DOE has concluded that testing WSHPs in accordance with 
AHRI 600-2023 would provide more representative results and more fully 
comply with the requirements of paragraph (2) of 42 U.S.C. 6314(a) than 
testing in accordance with the currently referenced standard ISO 13256-
1:1998, as discussed in more detail in section III.D.6 of this final 
rule. And while clear and convincing evidence is not needed when 
amending a test procedure under the 7-year-lookback, DOE finds that the 
test procedure amendments adopted here are supported by clear and 
convincing evidence as outlined in this final rule. DOE discusses the 
specific test procedure updates included in appendix C1, resulting from 
the incorporation by reference of AHRI 600-2023, in sections III.E and 
III.F of this final rule. Therefore, DOE is adopting an amended test 
procedure for WSHPs that incorporates by reference AHRI 600-2023, with 
minor deviations. With regard to the assertion by AHRI and MIAQ that 
any deviation from ASHRAE 90.1 requires quantification of the burden, 
and MIAQ's assertion that only modifications that reduce testing burden 
on manufacturers can be considered, DOE does not agree that EPCA 
requires DOE to consider only deviations that

[[Page 84197]]

would reduce burden. Rather, EPCA requires only that DOE ensure that 
test procedures established are not unduly burdensome to conduct. (42 
U.S.C. 6314(a)(2))
    With regard to the assertion by AHRI and MIAQ that EPCA requires 
DOE to justify by clear and convincing evidence each amendment or 
difference from the industry test procedure referenced by ASHRAE 90.1, 
DOE does not agree that EPCA requires such a line-by-line assessment of 
an amended test procedure. First, as stated previously, there is no 
requirement for clear and convincing evidence in EPCA for a test 
procedure amendment under the 7-year-lookback. Additionally, if DOE 
were amending a test procedure pursuant to the ASHRAE trigger, EPCA 
requires only that DOE shall amend the test procedure for the product 
as necessary to be consistent with the amended industry test procedure 
or rating procedure unless it determines, supported by clear and 
convincing evidence, that to do so would not meet the requirements of 
EPCA (42 U.S.C. 6314 (a)(4)(B)). If DOE makes such a determination, DOE 
may establish an amended test procedure, but there is no requirement 
for DOE to show, by clear and convincing evidence, that DOE's amended 
test procedure is reasonably designed to produce test results which 
reflect energy efficiency, energy use, and estimated operating costs 
during a representative average use cycle and are not unduly burdensome 
to conduct. (See 42 U.S.C. 6314(a)(2)). Additionally, if DOE does not 
make such a determination, there is no requirement that DOE show, by 
clear and convincing evidence, that an amended test procedure, which is 
consistent with the industry test procedure, is reasonably designed to 
produce test results which reflect energy efficiency, energy use, and 
estimated operating costs during a representative average use cycle and 
are not unduly burdensome to conduct.
2. Comments Regarding DOE's Test Procedure Development Process
    In response to the June 2022 NOPR, DOE received comments regarding 
its rulemaking development process. AHRI recommended that DOE follow a 
transparent, cooperative, or consensus-based regulatory development 
process. (AHRI, No. 24 at p. 4) AHRI commented that, in the past, DOE 
has had difficulty duplicating test results without the help and 
guidance of manufacturers and AHRI testing facilities and that the 
complex controls and operational characteristics of WSHP equipment 
require manufacturer and testing facility experience to test properly. 
(Id.) AHRI acknowledged that DOE has tested 15 units from the WSHP 
industry but stated that DOE did not release the data and results of 
the testing. (Id.) AHRI expressed further concern that the testing 
cited in the August 2022 NOPR was not shared with the relevant AHRI 
committee and requested that DOE share the results of its findings with 
stakeholders in order to allow for validation and review. (Id. at pp. 
2, 4)
    AHRI recommended that DOE work with industry on finalizing AHRI 
600, conduct any necessary testing or calculations to develop a 
document agreed upon by DOE and relevant stakeholders, and follow the 
proper procedures to introduce the finalized test procedure and updated 
efficiency standards in ASHRAE 90.1. (Id.) AHRI commented that it will 
support the necessary updates to the Federal procedure and metrics 
after DOE takes the aforementioned steps. (Id.)
    ClimateMaster commented that DOE did not follow a cooperative 
process to improve the test methods for WSHPs and that neither AHRI nor 
the WSHP industry was consulted in a working group setting with other 
stakeholders, which was inconsistent with past and current industry 
approaches. (ClimateMaster, No. 22 at p. 1)
    WaterFurnace commented that it believed a more transparent and 
consensus-based development process is warranted before DOE implements 
new WSHP test procedures and that DOE should seek industry and AHRI 
input in order to validate and review the testing results. 
(WaterFurnace, No. 20 p. 2) WaterFurnace recommended that DOE implement 
an Appliance Standards and Rulemaking Federal Advisory Committee 
(``ASRAC'') Working Group for all future undertakings to propose 
substantial changes in regulatory policy so as to work out complex 
issues in a common forum with industry and AHRI. (Id.)
    With respect to the comments from AHRI, ClimateMaster, and 
WaterFurnace, DOE notes that it may establish a negotiated rulemaking 
working group under ASRAC in accordance with the Federal Advisory 
Committee Act (``FACA'') and the Negotiated Rulemaking Act (``NRA'') (5 
U.S.C. 561-570, Pub. L. 104-320) to negotiate proposed test procedures 
and amended energy conservation standards if DOE determines that the 
use of the negotiated rulemaking process is in the public interest 
according to the requirements of FACA and in a manner consistent with 
the requirements of the NRA. However, in this rulemaking, DOE is 
following the traditional rulemaking notice-and-comment process.
    DOE recognizes the benefits of developing test procedures through a 
consensus-based process and notes that DOE has participated in the AHRI 
process and has worked with the AHRI Geothermal and WSHP STC in 
developing AHRI 600-2023, which is incorporated by reference in this 
final rule. As noted in the August 2022 NOPR, DOE has participated in 
AHRI committee meetings working to develop AHRI 600 since 2019. See 87 
FR 53302, 53308-53309. In particular, DOE brought up many of the 
concerns raised in August 2022 NOPR in ISO 13256-1 and AHRI 600 
meetings for several years prior to the publication of the August 2022 
NOPR, but the committees declined to address these issues in the draft 
industry test procedures at that time. At the time of drafting of the 
August 2022 NOPR, AHRI 600 was still in development and had not yet 
published. In the August 2022 NOPR, DOE outlined its understanding that 
the intent of AHRI 600 would be to provide a method for calculation of 
IEER for WSHPs based on testing conducted according to ISO 13256-
1:1998. Id. at 87 FR 53309. In the August 2022 NOPR, DOE tentatively 
concluded that the general methodology in AHRI 600 for determining IEER 
is appropriate. Id. However, DOE identified several aspects of the 
methodology that warrant further modifications. Id. In the August 2022 
NOPR, DOE noted that it could not speculate as to the substantive 
outputs of the ISO 13256-1 National deviation and the AHRI 600 
committee's efforts. Id. Consistent with DOE's procedure for notice-
and-comment rulemakings, DOE also conducted the NOPR public meeting 
that provided opportunity for stakeholders to provide feedback on DOE's 
proposals. The feedback DOE received in both NOPR public meeting 
comments and written comments was considered in subsequent AHRI 600 
committee meetings and drafting of this final rule.
    Since the publication of the August 2022 NOPR, DOE continued to 
work with industry in AHRI 600 committee, as recommended by commenters, 
to address the test procedure concerns DOE raised in the August 2022 
NOPR with the intent that a revised industry test procedure specific to 
WSHPs could be adopted in a final rule. Rather than continue to 
simultaneously modify and maintain ISO 13256-1 and AHRI-600, the 
committee members voted to merge them into a comprehensive unified test 
procedure, AHRI 600. More specifically, the methodology specified in 
ISO 13256-1 has been incorporated into

[[Page 84198]]

AHRI 600-2023. Therefore, AHRI 600-2023 does not reference ISO 13256-1.
    Regarding AHRI's comment about sharing data, DOE presented the 
results of its testing in the August 2022 NOPR. Id. at 87 FR 53314-
53317. Based on participation in AHRI 600 committee meetings following 
the August 2022 NOPR, additional data from DOE's investigative testing 
was not needed for the committee to reach resolution on the content of 
AHRI 600-2023.
    On September 11, 2023, AHRI 600-2023 was published. DOE notes that 
the statutory deadline for publishing a test procedure final rule for 
WSHPs was May 16, 2019. (42 U.S.C. 6314(a)(1)) Given EPCA's statutory 
requirement to review the appropriate test procedures for WSHPs every 
seven years, DOE has concluded that it would be neither appropriate nor 
permissible to delay the current rulemaking for the WSHP test procedure 
until after ASHRAE 90.1 adopts AHRI 600-2023 as the test procedure for 
WSHPs. To avoid any further delay, DOE is adopting a test procedure for 
WSHPs that incorporates by reference AHRI 600-2023, with minor 
deviations.
3. Comments Supporting the Adoption of AHRI 340/360-2022
    In response to the June 2022 NOPR, some commenters supported 
adopting AHRI 340/360-2022 in the WSHP test procedure. NEEA generally 
supported DOE's efforts to align the WSHP test procedure with other 
water-cooled unitary systems, including by integrating fan energy into 
the test procedure for ducted WSHPs. (NEEA, No. 25 at p. 1) In 
particular, NEEA supported DOE's proposal to align the WSHP test 
procedure with AHRI 340/360-2022 and ANSI/ASHRAE 37-2009. (Id. at p. 2) 
NEEA stated that aligning the testing of WSHPs with ANSI/ASHRAE 37-2009 
would ensure that WSHP ratings will be consistent with other water-
cooled and direct expansion cooling systems. (Id.) NEEA also supported 
the introduction of an IEER metric rather than rating only with EER. 
(Id.) NEEA stated that the proposed test procedure would impact the 
current modeling approach for WSHP standard reference systems used to 
determine total system performance ratio in the 2018 Washington State 
Energy Code, but NEEA acknowledged that potential advancements to the 
test procedure and ratings metric would provide an important 
improvement in representativeness for this equipment. (Id. at p. 1)
    NYSERDA generally supported DOE's proposed amendments for the WSHP 
test procedure and concurred with DOE's tentative determination that 
the changes would improve the representativeness of the WSHP test 
procedure. (NYSERDA, No. 21 at pp. 1-2) NYSERDA asserted that this 
would spur growth in the market for WSHPs, including geothermal heat 
pumps. (Id. at p.2)
    As discussed previously, in this final rule, DOE is incorporating 
by reference AHRI 600-2023 into appendix C1 in lieu of incorporating by 
reference AHRI 340/360-2022 as proposed in the August 2022 NOPR. DOE 
notes, however, that the majority of the technical content from the 
proposed test procedure in the August 2022 NOPR remains consistent in 
the test procedure finalized in this final rule. Any changes to 
technical provisions from the August 2022 NOPR proposal were due to 
industry consensus culminating in the AHRI 600-2023 standard. 
Throughout this final rule, DOE discusses in detail the technical 
differences between the test procedure proposed in the August 2022 NOPR 
and the version finalized in this final rule.
4. Comments Opposing the Adoption of AHRI 340/360-2022
    Other commenters opposed the proposal in the August 2022 NOPR to 
adopt AHRI 340/360-2022 in the WSHP test procedure. AHRI and MIAQ 
expressed concern that the impact on manufacturers of DOE's proposal to 
update the WSHP test procedure has not been quantified. (AHRI, No. 24 
at p. 2; MIAQ, No. 23 at p. 3) AHRI and MIAQ stated that the capability 
of testing WSHPs to AHRI 340/360-2022 has not been assessed by third-
part test labs. (Id.)
    AHRI and MIAQ noted that an ASRAC Working Group has been formed in 
an effort to negotiate test procedures and energy efficiency standards 
for CUAC/HPs, the scope of which stands to result in significant 
modifications to AHRI 340/360-2022 and the efficiency measures for such 
equipment. (AHRI, No. 24, at p. 2; MIAQ, No. 23 at p. 2) AHRI and MIAQ 
further noted, however, that WSHPs are outside the scope of these 
efforts, potentially leaving a significant gap in ratings (i.e., were 
WSHPs to be rated using AHRI 340/360). (Id.)
    WaterFurnace expressed concern regarding DOE's sampling and testing 
procedure for modifying AHRI 340/360, especially considering the 
complexity of the product's controls and operational characteristics 
and taking into account past instances in which DOE has struggled to 
duplicate test results without manufacturer and AHRI testing support. 
(WaterFurnace, No. 20 at p. 2)
    WaterFurnace agreed with AHRI's concerns that the impact on 
manufacturers of DOE's proposal to update test procedures has not been 
adequately quantified, nor was it clear whether third-party test labs 
have the capability to accommodate the proposed changes. (Id. at p. 2)
    WaterFurnace, ClimateMaster, Enertech, and FHP all expressed 
concern that DOE's proposal to test WSHPs using AHRI 340/360-2022 would 
require manufacturers to test WSHPs to two different test standards 
because geothermal applications for WSHPs would still require testing 
to ISO 13256-1. (WaterFurnace, No. 20 at p. 3; ClimateMaster, No. 22 at 
p. 1; Enertech, No. 19 at p. 1; FHP, No. 26 at p. 3) WaterFurnace noted 
that ISO 13256-1 is already referenced in several Federal, State, and 
local codes. (WaterFurnace, No. 20 at p. 3) WaterFurnace and 
ClimateMaster stated that implementing a dual certification process 
would be burdensome for manufacturers. (WaterFurnace, No. 20 at p. 3; 
ClimateMaster, No. 22 p. 1) Enertech also noted that Federal and State 
tax credits specifically reference ISO/AHRI 13256-1:1998 for efficiency 
ratings and that the ENERGY STAR specifications directly reference the 
ISO 13256-1:1998 standard for the ENERGY STAR Tier 3 efficiency 
requirements. (Enertech, No. 19 at p. 1)
    WaterFurnace asserted that DOE underestimated the significance and 
the burden that the proposed changes to the WSHP test procedure would 
impose upon manufacturers and industry players. (WaterFurnace, No. 20 
at p. 3) WaterFurnace identified the following assumptions and 
shortcomings in AHRI 340/360-2022 that it stated were not appropriately 
addressed in the August 2022 NOPR:
    (1) While the August 2022 NOPR stated that IEER can be calculated 
and an interpolation can be performed using existing data from ISO 
13256-1, WaterFurnace determined that the entering air, water flow, 
external static and airflow conditions differ from AHRI 340/360-2022, 
which will therefore require additional testing by the manufacturer and 
the implementation of a new certification program;
    (2) Currently, performance mapping capability is available across a 
wide range of entering water temperatures (``EWT'') used in modeling 
software such as EQuest and DOE's EnergyPlus, and all of this detail 
would be lost with the implementation of AHRI 340/360-2022 because it 
only presents a single IEER cooling metric and a single heating point;

[[Page 84199]]

    (3) Provisions should be added under AHRI 340/360-2022 for hybrid 
heat pumps, which are unique in their capability for refrigerant 
cooling with other non-refrigerant heating capability;
    (4) Provisions should be added under AHRI 340/360-2022 for split 
configurations, which are offered for smaller WSHPs;
    (5) Provisions should be added under AHRI 340/360-2022 for small 
WSHPs with non-ducted applications (e.g., console units), along with 
language that takes into account the fact that many of these units are 
installed into residential buildings with substantial heating that 
would not fit the AHRI 340/360-2022 conditions;
    (6) While DOE proposed to adopt heating test conditions for WSHPs 
that are not specified in AHRI 340/360-2022, this overlooks other 
testing requirements and language that would need to be addressed 
(e.g., minimum and maximum operating conditions) in order to adequately 
add heating tests to a cooling-only standard;
    (7) Provisions should be added under AHRI 340/360-2022 for 
antifreeze blends and their fluid characteristics (i.e., alcohols, 
salts, and glycols);
    (8) Test procedures would need to be modified to account for 
smaller WSHP units, as AHRI 340/360-2022 requires an airflow tolerance 
of less than 3 percent and is thus designed around larger product 
designs with drives and adjustable sheaves that accommodate this 
airflow capability;
    (9) Although AHRI 340/360-2022 is primarily an air-source standard 
that utilizes air and refrigerant enthalpy test methods, water-source 
equipment is more consistently and accurately tested with a liquid 
enthalpy test method and would need to use air or refrigerant enthalpy 
only as secondary methods--and, furthermore, this process would be 
inconsistent with part load measurements under AHRI 340/360-2022;
    (10) Manufacturer-specified liquid flow rate is preferred over the 
AHRI 340/360-2022 method of setting liquid flow rate using a 10 [deg]F 
temperature rise to establish flow rates;
    (11) Continuous 24/7 fan operation is an outdated idea according to 
ASHRAE 90.1; and
    (12) Issues addressed by Working Groups under ASRAC will likely 
result in massive changes to AHRI 340/360 regarding air-side 
measurements and will take focus away from necessary modifications to 
provisions for water-cooled units and, thus, changes for water-cooled 
units to AHRI 340/360 will likely be of secondary importance to the 
ASRAC committee. (Id. at pp. 3-4)
    WaterFurnace also commented that because AHRI 340/360-2022 is 
primarily an air-source standard, AHRI 340/360-2022's comparatively 
small water-cooled section is used to certify approximately 1,000 units 
per year in contrast to the 200,000 unit sales per year under the AHRI/
ISO 13256 certification programs. (Id. at p. 5) Therefore, WaterFurnace 
noted that moving testing of WSHPs (with much higher shipments) to the 
smaller water-cooled section of AHRI 340/360-2022 would not be logical 
considering the noted changes required. (Id.)
    WaterFurnace commented that changing to a different AHRI 340/360-
2022 standard and separating out geothermal applications to ISO 13256 
would be disruptive to both the water-source and geothermal industries 
at a time when the use of heat pumps is being encouraged by national, 
state, and local regulations as a carbon-reduction solution. (Id.) 
WaterFurnace stated that tax credits and rebates based upon AHRI/ISO 
13256 performance have been legislatively codified and will be 
difficult to change, and further noted that the Inflation Reduction Act 
references ASHRAE 90.1 and AHRI/ISO 13256 as a measurement of 
performance. (Id. at p. 6) WaterFurnace stated that other governmental 
programs such as ENERGY STAR have specifications and benefits based on 
AHRI/ISO 13256 performance certification and that decarbonization 
policy programs by utilities, cities, and states rely on such 
certification as well. (Id.)
    ClimateMaster commented that DOE would need to address the 
following issues with AHRI 340/360-2022:
    (1) AHRI 340/360-2022 needs to be updated to include the appendix 
C1 additions, a process that will likely be delayed by a current ASRAC 
working group undertaking to amend the current AHRI 340/360-2022 test 
procedures with a focus on air-source equipment;
    (2) AHRI 340/360-2022 does not include test requirements for water-
source heating;
    (3) AHRI 340/360-2022 does not include test provisions for non-
ducted equipment;
    (4) The airflow setting and tolerance specified by AHRI 340/360-
2022 does not cover or is incompatible with current WSHP equipment;
    (5) AHRI 340/360-2022 does not include a pump power adder for all 
equipment sizes, nor is DOE's proposal to utilize the pump power adder 
in AHRI 920 representative of installed WSHP systems;
    (6) AHRI 340/360-2022 does not include glycols or antifreeze 
solutions in the method of test, and the recommended solution is not 
representative of the fluids used for WSHPs in the field or test 
laboratories currently used in the development, qualification, and 
compliance processes; and
    (7) The refrigerant charging requirements included in AHRI 340/360-
2022 are not applicable, accurate, or relevant to WSHP systems. 
(ClimateMaster, No. 22 at pp. 1-2)
    Enertech commented that AHRI 340/360-2022 lacks testing parameters 
for water source heating, testing parameters for non-ducted equipment, 
testing methods utilizing antifreeze blends, and parameters for pump 
power adder for small equipment. (Enertech, No. 19 at p. 1) Enertech 
noted that AHRI 340/360-2022 requires a 3 percent airflow 
tolerance during testing, which Enertech asserted is unrealistic for 
small-capacity equipment. (Id.) For these reasons, Enertech disagreed 
that new efficiency ratings could be interpolated from conditions 
common to the WSHP industry and asserted that new testing would be 
required for all products offered by any manufacturer. (Id.) Enertech 
stated that adopting AHRI 340/360-2022 as the DOE test procedure for 
WSHPs would result in long-term disruptions to the geothermal and WSHP 
industries. (Id. at p. 2)
    FHP commented that adopting test methods per AHRI 340/360-2022 
would require additional testing effort, time, and resources, and would 
result in additional costs to the industry. (FHP, No. 26 at p. 3) FHP 
commented further that AHRI 340/360-2022 contains differences in 
standard test conditions that would require additional testing as well 
as changes to (1) the design of the units to ensure 10 [deg]F 
temperature rise on the water side and (2) the fan/motor selections and 
programs to maintain the proper air flow at defined static pressures 
and airflow tolerances. (Id.) FHP stated that the use of two standards 
may split the current WSHP product designs, thereby adding permanent 
design burden to current product offerings. (Id.)
    FHP stated that the proposed changes to the WSHP test procedure 
could be the most impactful regulatory issue for the WSHP industry and 
that the industry's resources are completely dedicated to the 
development of equipment that uses low-global warming potential 
refrigerants through January 1, 2025. (FHP, No. 26 at p. 5) FHP 
expressed concern about the impact of moving to an entirely new test 
procedure that would require re-testing, re-designing, and potentially 
re-certifying most of its basic model groups. (Id.) FHP also

[[Page 84200]]

expressed concerns about the additional resources and maintenance 
potentially required by having two separate product designs and 
validations for WSHPs. (Id.)
    FHP also stated that current AEDMs are based on the leading 
industry standard for these types of equipment. (Id. at p. 2) More 
specifically, FHP stated that its current AEDM is based on the ISO 
13256-1:1998 test standard and that DOE's proposal to reference AHRI 
340/360-2022 as the test procedure for WSHPs would require additional 
testing and new AEDMs. (Id.) FHP commented that even reduced testing to 
validate AEDMs would be unduly burdensome for such a small market. 
(Id.)
    During the public meeting, AAON commented that the amount of 
testing in the proposed test procedure was rather extreme and asked DOE 
to share the testing burden assessment. (Public Meeting Transcript, No. 
17 at p. 60)
    GeoExchange commented that manufacturers of geothermal heat pumps 
have significant concerns with the August 2022 NOPR as written and 
believe it will subject WSHPs and geothermal heat pumps to competing 
and inconsistent certification standards. (GeoExchange, No. 29 at p. 1) 
GeoExchange commented that these issues will complicate production of 
these products and increase costs for consumers. (Id.) GeoExchange 
stated that the timing of the August 2022 NOPR coincides with efforts 
by the industry to complete work on its development of a standard that 
recognizes the overlap between different applications of heat pump 
technology and minimizes unnecessary disruptions for manufacturers. 
(Id.)
    DOE appreciates these comments regarding the proposal to adopt AHRI 
340/360-2022 in the WSHP test procedure. As discussed, in this final 
rule, DOE is no longer adopting AHRI 340-360-2022 and is adopting 
instead an amended test procedure for WSHPs that incorporates by 
reference AHRI 600-2023. Because AHRI 600-2023 was developed through an 
industry consensus process subsequent to the timing of the August 2022 
NOPR comment period, DOE surmises that the testing approach specified 
in AHRI 600-2023 represents the prevailing industry consensus regarding 
the most appropriate method of testing WSHPs and addresses the issues 
raised by commenters regarding DOE's proposal to adopt AHRI 340/360-
2022 as the test procedure for WSHPs. See sections III.E and III.F of 
this final rule for discussion of specific test procedure topics raised 
by interested parties in response to the August 2022 NOPR.
    Further, in response to the test burden comments, DOE did quantify 
per-test burden of the proposed test procedure in the August 2022 NOPR 
and found that the proposed test procedure was not unduly burdensome to 
conduct. 87 FR 53302, 53340. A similar analysis is presented in this 
final rule (see section III.I of this document for details), and the 
same conclusion is reached. Additionally, as discussed in this 
document, DOE is adopting a test procedure incorporating by reference 
the industry consensus test standard, AHRI 600-2023. Therefore, DOE has 
determined that the amended test procedure will not increase burden as 
compared to the latest draft industry consensus test standard.
5. Comments Encouraging the Adoption of AHRI 600
    Numerous commenters encouraged DOE to adopt AHRI 600 in an amended 
WSHP test procedure in response to the August 2022 NOPR. AHRI 
recommended that DOE refrain from adopting AHRI 340/360-2022 for WSHPs 
in favor of continuing to collaborate with industry on finalizing AHRI 
600. (AHRI, No. 24 at p. 4) AHRI commented that AHRI 600 has been under 
development for several years and that, despite some delays, is 
steadily progressing. (Id.) AHRI commented that during the discussions 
for the development of AHRI 600, the committee considered applying AHRI 
340/360-2022 to calculate IEER. (Id.) AHRI commented that it continues 
to improve AHRI 600 test procedures (e.g., by resolving issues to fan 
power, external static pressure, water temperature, and subsequent 
efficiency levels) and that AHRI will continue committing to frequent 
meetings to satisfactorily resolve the issues raised in August 2022 
NOPR. (Id.)
    WaterFurnace stated that AHRI 600 draft standard was released in 
October 2022 and achieves the objectives of the August 2022 NOPR 
without industry distractions. (WaterFurnace, No. 20 p. 5) WaterFurnace 
commented that AHRI 600 standard is on track for committee review by 
October 31, 2023. (Id.)
    WaterFurnace stated that the quickest way to implement appropriate 
changes to WSHP test procedures would be to adopt versions of AHRI 600 
and ISO 13256-1, as modifying test procedures to comply with AHRI 340/
360-2022 would entail substantial changes that will delay the 
implementation process. (Id. at p. 4)
    WaterFurnace commented that it supports development of AHRI 600 
test procedure and recommended that the DOE test procedure reference it 
directly instead of AHRI 340/360-2022. (Id. at p. 5) WaterFurnace 
stated that the AHRI 600 standard can resolve most of the issues DOE 
identified in the August 2022 NOPR regarding the current WSHP test 
procedure. (Id.) WaterFurnace recommended that DOE re-evaluate the 
August 2022 NOPR proposal and support WaterFurnace's proposal to 
quickly adopt AHRI 600 and the national deviation updates to AHRI/ISO 
13256. (Id. at p. 11) WaterFurnace commented that doing so will help 
industry achieve DOE's desired goals faster and with less disruption. 
(Id.)
    WaterFurnace commented that it supports implementation of an 
updated AHRI/ISO 13256:1998 with a targeted national deviation and 
revised annexes. (Id. at p. 5) WaterFurnace commented that an updated 
AHRI/ISO 13256:1998 with a targeted national deviation can solve 
specific issues mentioned in the August 2022 NOPR regarding AHRI/ISO 
13256 with changes that would not be substantial, stating that the 
method of testing WaterFurnace follows aligns with the August 2022 
NOPR. (Id.) WaterFurnace commented that many of the issues raised by 
DOE center on specific issues and test methods currently in use that 
can be documented and solved with a national deviation from AHRI/ISO 
13256. (Id.) WaterFurnace stated that it has developed a draft of this 
national deviation that will address the noted shortcomings and can be 
completed in a similar time frame as AHRI 600 approval. (Id.)
    ClimateMaster commented that DOE's proposal to move WSHPs to AHRI 
340/360-2022 would create too significant a change in the industry and 
instead recommended considering AHRI 600, which uses existing ISO/AHRI 
13256-1 certified data to mathematically calculate the system IEER. 
(ClimateMaster, No. 22 at p. 1) ClimateMaster further commented that 
DOE should consider updating the ISO/AHRI 13256-1:1998 standard to 
include national deviations to address specific issues such as: (1) 
modifying refrigerant charging and airflow/ESP requirements; and (2) 
the need to include a reference to ASHRAE 37 and provisions for air 
sampling for air-side capacity measurements. (Id. at p. 2)
    Enertech suggested adopting AHRI 600 for calculating IEER rather 
than the AHRI 340/360-2022 method. (Enertech, No. 19 at p. 2)
    MIAQ recommended that DOE work with industry to finalize AHRI 
Standard 600, conduct any necessary testing/calculations to develop a 
crosswalk, and follow proper procedures to introduce the finalized 
procedure and updated

[[Page 84201]]

efficiency standards in ASHRAE 90.1. (MIAQ, No. 23 at p. 9)
    Trane recommended that DOE move from a full-load metric and test 
procedure to one that is more representative of an energy use cycle, 
such as a part-load test procedure. (Trane, No. 28 at p. 3) Trane 
commented that the most accurate and representative test procedure is 
AHRI 600, not AHRI 340/360-2022 as proposed in the August 2022 NOPR. 
(Id.) Trane noted that AHRI 600 draft is now published and seeking 
public comments for the final version. (Id. at p. 2)
    As discussed, in this final rule, DOE is adopting an amended test 
procedure for WSHPs incorporating by reference AHRI 600-2023. As noted 
in the previous discussion, the methodology specified in ISO 13256-1 
has been incorporated into the AHRI 600-2023, which represents the 
latest industry consensus test standard for WSHPs and moves away from 
using ISO 13256-1, thus rendering unnecessary a national deviation to 
ISO 13256-1. Having been developed through an industry consensus 
process subsequent to the timing of the August 2022 NOPR comment 
period, DOE surmises that the testing approach specified in AHRI 600-
2023 represents the prevailing industry consensus regarding the most 
appropriate method of testing WSHPs.
6. Finalized DOE Test Procedure
    In summary, DOE is adopting an amended test procedure for WSHPs 
that incorporates by reference AHRI 600-2023, with minor deviations, in 
this final rule. DOE has determined that the test methods specified in 
AHRI 600-2023 (which are largely consistent with the provisions adopted 
in appendix C1 of this final rule) would produce test results that 
better reflect energy efficiency of WSHPs during a representative 
average use cycle than the current DOE test procedure and ISO 13256-
1:1998. DOE notes that the IEER metric is representative of cooling 
efficiency for WSHPs on an annual basis and is more representative than 
the current EER metric, which captures the system performance at a 
single, full-load operating point. DOE also notes that the other test 
procedure amendments incorporated in this final rule better ensure 
accurate and repeatable measurements and ensure that representative 
test conditions are maintained during testing. These changes include:
    (1) Minimum ESP requirements, instructions for setting airflow and 
ESP, and tolerances for airflow and ESP;
    (2) Operating tolerance for voltage;
    (3) Different indoor air conditions for testing;
    (4) Refrigerant charging instructions for cases where they are not 
provided by the manufacturer;
    (5) Use of the primary capacity measurement (i.e., indoor air 
enthalpy method) as the value for capacity, and different provisions 
for required agreement between primary and secondary capacity 
measurements;
    (6) Provisions for split systems, such as accounting for compressor 
heat and refrigerant line losses;
    (7) Measurement of duct losses for ducted units;
    (8) Standardized heat capacity of water and brine; and
    (9) A calculation for discharge coefficients.
    The subsequent sections of this final rule discuss aspects of the 
finalized test procedure that differ from the proposal in the August 
2022 NOPR. DOE has determined that these updates improve the 
representativeness of the test procedure for WSHPs. These include but 
are not limited to:
    (1) Updated pump power adder, developed during the AHRI 600-2023 
process;
    (2) ESP requirements for large units >65,000 Btu/h consistent with 
levels from the December 2022 term sheet of recommendations regarding 
test procedures for air-cooled commercial unitary air conditioners and 
heat pumps (``ACUACs and ACUHPs''), referred to hereafter as ``the 
ACUAC and ACUHP Working Group TP Term Sheet'' (See Document No. 65 in 
Docket No. EERE-2022-BT-STD-0015);
    (3) No option to physically test at the IEER conditions and to 
instead require testing at all three ISO 13256-1:1998 conditions;
    (4) Updated part-load EWT;
    (5) Specifying a maximum water flow rate instead of fixed inlet and 
outlet water conditions;
    (6) Different test provisions for coil-only units, including 
adjustments to default fan power;
    (7) Different required fluid--a methanol solution--and different 
fluid properties specified;
    (8) Some changes to airflow provisions, which are consistent with 
DOE's test procedure for central air conditioners and heat pumps at 
appendix M1 to subpart B of 10 CFR part 430 instead of AHRI 340/360-
2022;
    (9) IEER cyclic degradation equation that does not assume 
continuous fan operation; and
    (10) Heating test temperature of 50 [deg]F instead of 55 [deg]F.
    As discussed, DOE recognizes that the test method in AHRI 600-2023 
and incorporated by reference into appendix C1 represents an industry 
consensus test procedure that is likely to be considered for future 
updates to ASHRAE 90.1.
    Accordingly, for the foregoing reasons and those discussed in the 
subsequent sections of this final rule, DOE is incorporating by 
reference AHRI 600-2023 into the amended Federal test procedure for 
WSHPs. DOE has determined that the amended test procedure is reasonably 
designed to produce results that are representative of the energy 
efficiency of that covered equipment during an average use cycle and is 
not unduly burdensome to conduct. DOE notes also that use of appendix 
C1 will not be required until the compliance date of any amended 
standards denominated in terms of IEER, should DOE adopt such 
standards.

E. Efficiency Metrics

1. IEER
    As discussed previously, DOE's current test procedure for WSHPs 
measures cooling-mode performance in terms of the EER metric, the 
current regulatory metric. 10 CFR 431.96. EER captures WSHP performance 
at a single, full-load operating point in cooling mode (i.e., a single 
EWT) and does not provide a seasonal or load-weighted measure of energy 
efficiency. A seasonal metric is a weighted average of the performance 
of cooling or heating systems at different outdoor conditions intended 
to represent average efficiency over a full cooling or heating season. 
Several categories of commercial package air-conditioning and heating 
equipment are rated using a seasonal or part-load metric, such as IEER. 
IEER is a weighted average of efficiency at four load levels 
representing 100, 75, 50, and 25 percent of full-load capacity, each 
measured at a specified outdoor condition that is representative of 
field operation at the given load level. In general, the IEER metric 
provides a more representative measure of field performance than EER by 
weighting the full-load and part-load efficiencies by the average 
amount of time equipment spends operating at each load level. Table 1 
of ISO 13256-1:1998, the industry test standard incorporated by 
reference into DOE's current WSHP test procedure, and Table 2 of ISO 
13256-1:2021 both specify EWT conditions to be used for developing 
part-load ratings of EER for WSHPs with capacity control (tested at 
minimum compressor speed). However, part-load EER ratings are not 
addressed in the current DOE test procedure. Further, each part-load 
rating captures operation only at a single compressor speed and EWT

[[Page 84202]]

condition rather than operation across a range of temperatures and 
compressor speeds, as would be captured by an IEER metric. Neither ISO 
13256-1:1998 nor ISO 13256-1:2021 include seasonal metrics.
    In the August 2022 NOPR, DOE tentatively determined that use of a 
seasonal efficiency metric would be more representative of the average 
use cycle of a unit as compared to the current EER metric. 87 FR 53302, 
53313. Accordingly, DOE proposed to adopt certain provisions of AHRI 
340/360-2022 and use the IEER metric specified in section 6.2 of AHRI 
340/360-2022 for WSHPs. Id. Specifically, DOE proposed that IEER for 
WSHPs be calculated based on the EWT conditions specified in Table 9 of 
AHRI 340/360-2022 (i.e., 85 [deg]F, 73.5 [deg]F, 62 [deg]F, and 55 
[deg]F). Id. DOE referred to the approach of testing at these AHRI 340/
360-2022 EWTs as ``option 1'' in the August 2022 NOPR. Id. at 87 FR 
53316.
    In addition, DOE acknowledged in the August 2022 NOPR that adopting 
the IEER metric for WSHPs would increase the number of required 
cooling-mode tests from one to four. Id. at 87 FR 53313. DOE also 
discussed its understanding that the future updated version of AHRI 600 
would provide for calculating IEER from test results measured at the 
EWTs specified in Table 1 of ISO 13256-1:1998. Id. DOE stated that 
determining IEER via interpolation and extrapolation from testing at 
the ISO 13256-1:1998 EWTs, rather than from additional testing at the 
IEER EWTs specified in AHRI 340/360-2022, may reduce overall testing 
burden for manufacturers. Id. at 87 FR 53314. Consistent with this 
approach, DOE also proposed to allow determination of IEER via 
interpolation and extrapolation (``option 2'') based on testing at the 
full-load and part-load EWT conditions specified in Table 1 of ISO 
13256-1:1998 (i.e., 86 [deg]F, 77 [deg]F, and 59 [deg]F for full-load 
tests and 86 [deg]F, 68 [deg]F, and 59 [deg]F for part-load tests). Id. 
at 87 FR 53316. DOE proposed that the tests for option 2 would be 
performed using the same test provisions (aside from the EWTs) from 
AHRI 340/360-2022, ANSI/ASHRAE 37-2009, and sections 2 through 4 and 7 
of proposed appendix C1 as the tests for option 1. Id.
    In the August 2022 NOPR, DOE presented test data that indicated 
that determining EER by interpolating/extrapolating cooling capacity 
and total power would result in closer agreement to tested values than 
directly interpolating/extrapolating EER. Id. at 87 FR 53314-53315. 
Based on these findings, DOE proposed to specify interpolation/
extrapolation using the cooling capacity and total power as opposed to 
EER directly. Id. at 87 FR 53316. DOE also presented data in the August 
2022 NOPR indicating that for variable-speed WSHPs with higher (i.e., 
better) EER performance at intermediate compressor speeds than at 
maximum or minimum compressor speeds, the proposed interpolation and 
extrapolation method would result in a lower (i.e., worse) calculated 
IEER than testing at the IEER conditions specified in AHRI 340/360-
2022. Id. at 87 FR 53315-53316. DOE discussed its understanding from 
participation in AHRI 600 committee meetings that many manufacturers 
would prefer the option to use the interpolation and extrapolation 
method for variable-speed WSHPs, even if it results in lower IEER 
ratings, because it would result in less overall testing burden than 
testing at each of the AHRI 340/360-2022 conditions. Id. at 87 FR 
53316.
    DOE also proposed that if represented values for a basic model are 
determined with an AEDM, the AEDM could use either option 1 or option 2 
for determining IEER per the proposed test procedure in appendix C1. 
Id.
    DOE requested comment on the proposal to allow determination of 
IEER using two different methods: (1) testing in accordance with AHRI 
340/360-2022; or (2) interpolation and extrapolation of cooling 
capacity and power values based on testing in accordance with the 
proposed test procedure at the EWTs specified in Table 1 of ISO 13256-
1:1998. Id. DOE sought feedback on the proposed method for calculating 
IEER via interpolation and extrapolation, and on whether this approach 
would serve as a potential burden-reducing option as compared to 
testing at the AHRI 340/360-2022 conditions. Id. DOE also requested 
comment on whether the proposed methodology to determine IEER based on 
interpolation and extrapolation is appropriate for variable-speed 
units. Id. DOE noted it would consider requiring variable-speed 
equipment be tested only according to AHRI 340/360-2022 and, thus, 
testing physically at the IEER EWTs, if suggested by commenters. Id. 
Finally, DOE sought feedback on whether the proposed interpolation and 
extrapolation method should be based on testing at the ISO 13256-1:2021 
EWTs (which differ from the ISO 13256-1:1998 EWTs for certain test 
points). Id.
    Some commenters opposed DOE's proposals regarding the IEER metric 
in the August 2022 NOPR. ClimateMaster, MIAQ, and WaterFurnace 
recommended that DOE adopt the test methods specified in AHRI 600 
instead of AHRI 340/360-2022 for calculating the IEER of WSHPs. 
(ClimateMaster, No. 22 at pp. 3-5; MIAQ, No. 23 at p. 4; Waterfurnace, 
No. 20 at pp. 6-7) MIAQ stated that AHRI 600 will provide a method for 
calculating a seasonal cooling efficiency metric for WSHPs (i.e., IEER) 
based on testing conducted according to ISO 13256-1:1998. (MIAQ, No. 23 
at p. 4) MIAQ stated that that the estimated AHRI 600 approval date of 
October 1, 2023 would meet DOE's timeline for adopting the standard. 
(Id.) ClimateMaster commented that adopting the test methods specified 
in AHRI 340/360-2022 would require manufacturers to certify products 
under two programs (i.e., AHRI 340-360 and ISO/AHRI 13256), which is 
unprecedented in the industry, and would pose challenges for 
manufacturers, third-party labs, and partners to test and maintain two 
certification programs. (ClimateMaster, No. 22 at p. 3)
    ClimateMaster recommended that DOE utilize data created through ISO 
13256-1:1998 to interpolate per the procedure provided in AHRI 600. 
(ClimateMaster, No. 22 at p. 4) ClimateMaster disagreed with DOE's 
proposal for ``option 2'' to interpolate and extrapolate cooling 
capacity and total power instead of directly interpolating/
extrapolating EER and argued that the method in the draft AHRI 600 at 
the time should be used, which is based on directly interpolating/
extrapolating EER. (Id.) ClimateMaster further argued that the 
difference between the two methodologies is within the uncertainty of 
measurement for testing WSHPs and, therefore, that DOE's proposed 
deviation from the methodology in AHRI 600 (at the time) is 
unnecessary. (Id.) ClimateMaster further commented that their analysis 
of a random sample of performance data for five systems tested in their 
labs showed that, on average, interpolating/extrapolating based on EER 
resulted in slightly more accurate numbers than interpolating/
extrapolating based on capacity and power. (Id. at pp. 4-5)
    ClimateMaster recommended that DOE maintain the existing ISO 13256-
1:1998 standard until the WSHP industry adopts the updated standard and 
suggested that DOE adopting a national deviation of ISO 13256-1:2021 
would be practical as long manufacturers are given significant time to 
adopt the new test procedure. (ClimateMaster, No. 22 at p. 5) 
ClimateMaster commented that there are several changes introduced in 
ISO 13256-1:2021 that it believes provide a more effective performance 
map for a

[[Page 84203]]

WSHP system, but that this standard has not yet been adopted by the 
WSHP industry. (Id.) ClimateMaster further commented that the EWTs 
utilized for determining IEER via interpolation/extrapolation are 
irrelevant as long as DOE requires that the entering air temperatures 
and other items are inconsistent from the current ISO 13256-1:1998 test 
program. (Id.)
    Regarding DOE's request for comment on variable-speed unit testing, 
ClimateMaster commented that DOE's test results from the units sampled 
and tested at a third-party lab should be shared with stakeholders for 
review and comment--particularly regarding variable speed units, as 
most of these require hardware and software from the manufacturer to 
allow for proper testing, and test instructions were not provided to 
DOE for the department's testing of variable-speed units as would be 
done for normal certification testing. (ClimateMaster, No. 22 at p. 4)
    MIAQ commented that the proposed interpolation and extrapolation 
method should be based on testing at the ISO 13256-1:2021 EWTs. (MIAQ, 
NO. 23 at p. 4) Regarding the proposed ``option 2'' approach for 
determining IEER via interpolation/extrapolation for variable-speed 
units, MIAQ recommended DOE use the latest edition of ISO 13256-1:2021 
as the test procedure and continue to use AHRI 340/360-2022 for IEER 
calculations. (Id.)
    Other commenters supported DOE's proposals regarding the IEER 
metric in the August 2022 NOPR. The Joint Commenters supported adopting 
a part-load metric to measure cooling efficiency performance, stating 
that WSHPs, like many other commercial air conditioners and heat pumps, 
operate a significant percent of the time at part-load conditions, and 
that a part-load metric could incentivize designs that reduce annual 
energy consumption. (Joint Commenters, No. 27 at pp. 1-2) The Joint 
Commenters recommended DOE ensure that an adopted part-load metric 
reflects the total cooling provided divided by the total energy 
consumed and noted that they have previously commented that the IEER 
metric likely does not reflect the total cooling provided divided by 
the total energy consumed, and instead weights efficiencies calculated 
at different load-points. (Id.)
    NEEA supported DOE's proposed transition from regulating WSHP 
efficiency based on a full-load EER metric to a multi-capacity IEER 
metric. (NEEA, No. 25 at p. 2) NEEA commented that an IEER metric is 
more representative of overall equipment performance, and that 
optimizing part-load efficiencies is beneficial to both consumers and 
utilities because heating/cooling equipment operates at peak capacity 
for a small number of hours. (Id.) NEEA recommended that DOE move to 
the IEER metric for regulatory purposes while still encouraging 
manufacturers to also publish full-load EER data, given the importance 
of EER data for peak load performance and planning for utilities. (Id.) 
NEEA commented that it is encouraged by DOE's monitoring of the 
development of the AHRI Standard 600 and stated that this standard will 
allow for even more representative ratings of regional seasonal heating 
and cooling efficiencies. (Id.)
    NYSERDA supported DOE's proposal to adopt for WSHPs the testing 
methods specified in AHRI 340/360-2022 for calculating IEER, stating 
that a seasonal efficiency metric is more representative of the part-
load operation and varying temperature conditions seen in actual field 
performance of WSHPs. (NYSERDA, No. 21 at p. 2)
    As discussed in section III.D, DOE is incorporating by reference 
AHRI 600-2023 into its amended WSHP test procedure. Section 6.3 of AHRI 
600-2023 uses a method for determining IEER that is similar to the 
interpolation method proposed in the August 2022 NOPR, including tests 
at three EWTs, interpolating from those EWTs to the IEER EWTs specified 
in AHRI 340/360-2022, and adjusting the efficiency from the tested and 
interpolated load percentages to the IEER load percentages.
    With regards to ClimateMaster's comment on the interpolation 
methodology (i.e., interpolating the capacity and power vs. 
interpolating EER directly), DOE discussed this issue with stakeholders 
in AHRI 600 meetings after publication of the August 2022 NOPR, and 
section 6.3.4 of AHRI 600-2023 includes interpolation of capacity and 
power, consistent with the approach proposed in the August 2022 
NOPR.\7\ Having been developed through an industry consensus process 
subsequent to the timing of the August 2022 NOPR comment period, DOE 
surmises that the interpolation approach specified in AHRI 600-2023 
represents the prevailing industry consensus regarding the most 
appropriate method of performing the interpolation of capacity and 
power and addresses the issues raised by commenters regarding DOE's 
proposed methodology for the interpolation method in the August 2022 
NOPR.
---------------------------------------------------------------------------

    \7\ As discussed later in this section, the lowest EWT in AHRI 
600-2023 is 50 [deg]F, which is lower than the lowest IEER EWT (55 
[deg]F), such that the AHRI 600-2023 approach does not require 
extrapolation for determining IEER.
---------------------------------------------------------------------------

    With regards to the comment from the Joint Commenters recommending 
that DOE adopt a part-load metric that reflects the total cooling 
provided divided by the total energy consumed, DOE notes that no 
industry test procedures for WSHPs include a metric using such an 
equation format instead of the equation format for IEER (which is a 
weighted average of EERs at four different EWTs) and the Joint 
Commenters did not provide sufficient information to support 
development of such an equation format for WSHPs. Therefore, at this 
time, DOE has concluded that it lacks the necessary information to 
adopt an integrated metric other than IEER for WSHPs.
    While much of the methodology to determine IEER adopted in this 
final rule is consistent technically with the proposal from the August 
2022 NOPR, DOE notes the following differences between the approach 
adopted in this final rule (consistent with AHRI 600-2023) and the 
proposals in the August 2022 NOPR:
    (1) Removal of option for testing directly at IEER EWTs. In this 
final rule, DOE is not adopting the proposed option 1 methodology of 
directly testing at the IEER EWTs (i.e., 85 [deg]F, 73.5 [deg]F, 62 
[deg]F, 55 [deg]F). Rather, consistent with section 6.3 of AHRI 600-
2023, the test procedure adopted in this final rule specifies that IEER 
is determined via interpolation from tests at ISO 13256-1 EWTs, which 
is similar to option 2 as proposed in the August 2022 NOPR. With 
regards to NYSERDA's comment supporting adopting AHRI 340/360-2022 to 
calculate IEER, DOE notes that the methodology specified in AHRI 600-
2023 is very similar and produces near identical results to the 
methodology of AHRI 340/360-2022, as demonstrated through DOE's data 
presented in the August 2022 NOPR. See 87 FR 53302, 53316.
    (2) Change in full-load test EWTs. The full-load test temperatures 
used for interpolation in section 6.2.1 of AHRI 600-2023 are consistent 
with ISO 13256-1:2021 (i.e., 86 [deg]F, 68 [deg]F, 50 [deg]F) instead 
of ISO 13256-1:1998 (i.e., 86 [deg]F, 77 [deg]F, 59 [deg]F), which was 
proposed in the August 2022 NOPR. This is also consistent with the 
comment from MIAQ that encouraged the use of ISO 13256-1:2021 EWTs.
    (3) Change in part-load test EWTs. The part-load test EWTs used for 
interpolation in section 6.3.2 of AHRI 600-2023 are the same as the 
full-load EWTs (i.e., 86 [deg]F, 68 [deg]F, 50 [deg]F). This differs 
from the approach in the August 2022 NOPR, which proposed to align

[[Page 84204]]

with the EWTs specified in ISO 13256-1:1998 (i.e., 86 [deg]F, 77 
[deg]F, and 59 [deg]F for full-load tests; 86 [deg]F, 68 [deg]F, and 59 
[deg]F for part-load tests). MIAQ encouraged the use of ISO 13256-
1:2021, which specifies part-load test EWTs of 77 [deg]F, 59 [deg]F, 
and 41 [deg]F. The part-load EWTs in section 6.3.2 of AHRI 600-2023 (86 
[deg]F, 68 [deg]F, 50 [deg]F) are not consistent with either the 1998 
or 2021 versions of ISO 13256-1, and instead reflect the conclusion of 
discussions in AHRI 600 committee meetings that conducting part-load 
tests at the same EWTs as full-load tests would reduce testing burden 
(by reducing the number of times the water temperature would need to be 
reconditioned between tests) and better align with the IEER methodology 
in AHRI 340/360-2022. DOE surmises that the part-load EWTs specified in 
section 6.3.2 of AHRI 600-2023 represent the prevailing industry 
consensus regarding the most appropriate EWTs for testing WSHPs. In 
addition, as compared to the part-load EWTs proposed in the August 2022 
NOPR (the lowest of which was 59 [deg]F), the lowest part-load EWT in 
AHRI 600-2023 (50 [deg]F) is lower than the lowest IEER EWT (55 
[deg]F). Therefore, use of the part-load EWTs in AHRI 600-2023 means 
that all IEER EWTs can be interpolated from the tested EWTs, instead of 
requiring any extrapolation. As a result, in this final rule DOE is 
adopting the part-load EWTs as outlined in the AHRI 600-2023 through 
incorporation by reference.
    (4) Updated provisions for variable speed units. The approach for 
determining IEER for variable-speed WSHPs specified in AHRI 600-2023 
differs from the approach proposed in the August 2022 NOPR in that 
additional tests are required at intermediate compressor speeds. 
Specifically, section 6.3.2 of AHRI 600-2023 requires that three tests 
be performed at each EWT, at the three following compressor speeds: (1) 
maximum compressor speed (i.e., full-load test); (2) minimum compressor 
speed; and (3) an intermediate compressor speed that reflects the 
compressor stage with a capacity closest to half-way between the 
capacities measured at the minimum and maximum compressor speeds. This 
third test reduces the range of compressor speeds over which 
interpolation must be conducted (i.e., interpolating between 
intermediate compressor speed and maximum or minimum compressor speeds, 
instead of between maximum compressor speed and minimum compressor 
speed), thus reducing the extent to which interpolated results might 
differ from unit performance at the IEER EWTs. DOE surmises that the 
approach for variable speed units specified in section 6.3.2 of AHRI 
600-2023 represents the prevailing industry consensus regarding the 
most appropriate method. Therefore, in this final rule, DOE is adopting 
the IEER determination method for variable-speed units from AHRI 600-
2023 through incorporation by reference into appendix C1 of section 
6.3.2. Additionally, DOE presumes this updated methodology resolves 
Climatemaster's request for DOE's variable speed test data, as DOE is 
adopting the industry consensus methodology.\8\
---------------------------------------------------------------------------

    \8\ Section 6.3.2.4 of AHRI 600-2023 further specifies that if 
the continuous capacities of two compressor modulation levels 
allowed by the controls at a single set of operating conditions are 
equidistant from the arithmetic mean of the capacities from the 
minimum and maximum compressor modulation levels at the same set of 
operating conditions, the intermediate compressor modulation level 
used for testing is the compressor modulation level with the lower 
capacity.
---------------------------------------------------------------------------

    (5) Change in cyclic degradation equation. See section III.E.1.a of 
this document for detailed discussion.
    Finally, DOE is defining ``IEER'' in 10 CFR 431.92 as a weighted 
average calculation of mechanical cooling EERs determined for four load 
levels and corresponding rating conditions, expressed in Btu/watt-hour 
and that IEER is measured per appendix C1 to subpart F of part 431 for 
water-source heat pumps.
a. Cyclic Degradation
    In the August 2022 NOPR, DOE proposed to adopt specific sections of 
AHRI 340/360-2022 in its amended test procedure for WSHPs, including 
section 6.2.3.2. 87 FR 53302, 53327. Equation 4 in section 6.2.3.2 of 
AHRI 340/360-2022 is used to calculate part-load EER for a unit that 
needs to cycle in order to meet the 75-percent, 50-percent, and/or 25-
percent load conditions required for the IEER metric. Id. Cycling is 
the term used to describe the process in which a unit's compressor is 
repeatedly turned off and on in order to meet a load that is lower than 
the unit's capacity at its lowest compressor stage. Id. Equation 4 of 
AHRI 340/360-2022 multiplies only the compressor power and condenser 
section power by the load factor and the coefficient of degradation, 
while the indoor fan power and controls power are not multiplied by 
these variables. Id. This means that equation 4 of AHRI 340/360-2022 
assumes that the indoor fan continues to operate when the compressor 
cycles off. Id.
    DOE requested comment on the proposal to adopt the cyclic 
degradation equation specified in section 6.2.3.2 of AHRI 340/360-2022 
for WSHPs, which assumes continuous indoor fan operation when the 
compressor cycles off. Id. at 87 FR 53328.
    ClimateMaster commented that the assumption of continuous fan 
operation in the AHRI 340/360 IEER calculations is neither 
representative of field operation nor is it in alignment with guidance 
provided by ASHRAE 90.1. (ClimateMaster, No. 22 at p. 3) ClimateMaster 
stated that, according to data it collected through consumer surveys, 
16 percent of installed systems cycle fan operation with the 
compressor, 52 percent operate the fan continuously while a building is 
occupied but cycle the fan with the compressor when unoccupied, and 
only 14 percent of installed WSHPs run the fan continuously regardless 
of occupancy and compressor operation, while the remaining 18 percent 
responded that they were unaware of how their WSHP system cycles 
operated. (Id. at p. 3) ClimateMaster recommended that DOE instead use 
AHRI 600 method that does not assume continuous fan operation. (Id. at 
p. 8) ClimateMaster commented that, for WSHPs that are installed to 
operate the fan continuously, models with a multi-speed motor will 
operate at the cooling fan speed, while variable-speed models have an 
option to adjust the continuous fan speed to a lower value. (Id.)
    WaterFurnace commented that supporting ISO 13256 and AHRI 600 would 
solve the issue. (WaterFurnace, No. 20 at p. 8) WaterFurnace stated 
that continuous indoor fan operation is not the most appropriate logic 
in cooling-dominated environments and recommended demand controls 
ventilation as a better use of energy that improves latent moisture 
removal. (Id.)
    In response to these comments, DOE notes that section 6.3.6.4 of 
AHRI 600-2023 has an equation similar to equation 4 of AHRI 340/360-
2022, but the equation in AHRI 600-2023 assumes that the indoor fan 
stops operating whenever the compressor cycles off. The data provided 
by ClimateMaster suggest that the vast majority of installed WSHPs do 
not operate the fan continuously in all operating modes, but that many 
installed WSHPs do operate the fan continuously during occupied hours 
(i.e., regardless of whether the compressor is cycled on or off). At 
the time of publication of the August 2022 NOPR, there were no WSHP 
industry consensus test procedures that included IEER. However, at this 
time, DOE surmises that the method in section 6.3.6.4 of AHRI 600-2023, 
which assumes the fan does not run when the compressor is cycled off, 
represents

[[Page 84205]]

industry consensus on the appropriate method for determining IEER for 
WSHPs. At this time, DOE has concluded that it lacks sufficient 
information to justify deviating from the approach in AHRI 600-2023 
regarding fan operation. DOE is therefore incorporated by reference the 
cyclic degradation equation from section 6.3.6.4 of AHRI 600-2023 into 
its amended test procedure in this final rule.
2. ACOP
    DOE's current test procedure for WSHPs measures heating-mode 
performance in terms of the COP metric. COP is a full-load heating 
efficiency metric for WSHP water-loop applications, meaning that it 
represents the heating efficiency for a WSHP operating at its maximum 
capacity at an EWT that is typical of heating operation in water-loop 
applications. DOE's current test procedure specifies an EWT of 68 
[deg]F for measuring COP. 10 CFR 431.96.
    In the August 2022 NOPR, DOE discussed its understanding that while 
in the past water-loop temperatures were maintained at temperatures 
above 60 [deg]F via heat provided by a system boiler, in current 
practice WSHP installations are typically controlled to allow water-
loop temperatures to drop to temperatures closer to 50 [deg]F. 87 FR 
53302, 53316. Therefore, while the current EWT of 68 [deg]F for the COP 
metric may have been more representative of how WSHP systems were 
controlled in the past (i.e., with a boiler maintaining water-loop 
temperatures above 60 [deg]F), DOE tentatively determined in the August 
2022 NOPR that the EWT specified for determining COP should be no 
higher than the lowest EWT used in the IEER metric, which is 55 [deg]F 
(for the 25-percent load point). Id. Therefore, DOE tentatively 
concluded in the August 2022 NOPR that the COP metric would be more 
representative of water-loop WSHP applications if based on an EWT of 55 
[deg]F. Id. at 87 FR 53317. Accordingly, in the August 2022 NOPR, DOE 
proposed use an EWT of 55 [deg]F for the COP metric in appendix C1. Id.
    DOE also considered whether an EWT below 55 [deg]F, specifically 50 
[deg]F, might be more representative for determining COP, depending 
upon typical heating conditions for water-loop WSHPs. Id. However, DOE 
noted in the August 2022 NOPR that it lacked data or evidence 
indicating that 50 [deg]F would be a more representative heating EWT 
than 55 [deg]F for WSHPs. Id.
    Additionally, DOE proposed to include an alternate method in 
appendix C1 that would allow manufacturers to determine COP at the 
proposed EWT of 55 [deg]F by interpolation from results of testing at 
the EWTs specified in Table 2 of ISO 13256-1:1998 (i.e., 50 [deg]F and 
68 [deg]F). Id. In the August 2022 NOPR, DOE presented the results of 
investigative testing demonstrating that COP calculated from 
interpolated values of cooling capacity and total power differed from 
measured COP by an average of less than 1 percent. Id. Based on these 
test results, DOE tentatively concluded that determining COP at 55 
[deg]F via interpolation from testing at the ISO 13256-1:1998 EWTs (in 
accordance with DOE's proposed test procedure) would provide 
appropriately representative results that are comparable to testing at 
55 [deg]F. Id.
    In summary, DOE proposed in section 6.2 of the proposed appendix C1 
to allow that COP for WSHPs can be calculated from either of two 
methods: (1) ``option A''--testing at 55 [deg]F; or (2) ``option B''--
interpolation of heating capacity and power values based on testing in 
accordance with the proposed test procedure at EWTs of 50 [deg]F and 68 
[deg]F. Id.
    DOE sought comment and data on the representativeness of 55 [deg]F 
as the EWT condition for determining COP. Id. Specifically, DOE 
requested feedback and data on whether a lower EWT, such as 50 [deg]F, 
would be more representative of heating operation of WSHPs. Id. DOE 
stated that it would further consider any alternate EWT suggested by 
comments in developing any final rule. Id. DOE also requested comment 
on the proposal to allow determination of COP using the two different 
methods. Id. Specifically, DOE sought feedback on the proposed method 
for calculating COP via interpolation and on whether this approach 
would serve as a potential burden reducing option as compared to 
testing at 55 [deg]F. Id.
    In response to the August 2022 NOPR, ClimateMaster recommended that 
DOE maintain use of the ISO 13256-1:1998 EWT of 68 [deg]F as the basis 
for the regulated metric, asserting that this would take into account 
the fact that building designers select and simulate system equipment 
and performance based upon data published by manufacturers. 
(ClimateMaster, No. 22 at p. 5) ClimateMaster stated that the EWT used 
for heating operation in a WSHP is dependent on many factors (e.g., 
building design, location, system design, system operation, and 
building occupancy or use) and that, due to these factors, there are no 
data available to determine the representativeness of 55 [deg]F as the 
EWT condition in contrast to a lower or higher EWT. (Id.)
    Regarding DOE's proposal to allow two different options for 
determining COP, ClimateMaster stated that it disagreed with both 
proposed options for allowing determination of COP, stating that 
neither option would provide a reduction in burden considering DOE's 
proposal to change entering air temperatures. (Id.) ClimateMaster 
further commented that the proposed changes would require the industry 
to test under multiple standards to meet both certification programs. 
(Id. at pp. 5-6)
    MIAQ recommended aligning the EWT conditions with the latest 
edition of ISO standard EWT conditions. (MIAQ, No. 23 at p. 4)
    WaterFurnace commented that non-expansion valve products typically 
cannot operate below an EWT of 60 [deg]F and that a percentage of the 
market has always had limited water temperature range capability. 
(WaterFurnace, No. 20 at p. 7) WaterFurnace also commented that 
adopting ISO 13256-1 and AHRI 600 would solve the issue of COP test 
temperature. (Id.)
    Regarding considerations for selecting the EWT condition for 
determining COP, FHP commented that the use of higher EWTs is focused 
on water loop condition only and the move to electrification for 
commercial buildings will shift commercial designs for water source 
products toward ground coupled systems, driving temperatures closer to 
ISO 13256-1 ground loops conditions (e.g., 32 [deg]F entering water). 
(FHP, No. 26 at p. 4)
    NYSERDA agreed with DOE's proposal to adopt an EWT of 55 [deg]F or 
lower, stating that geothermal technology research and development 
undertaken by NYSERDA and the Cleaner, Greener Communities Program in 
Syracuse revealed the average EWT for the average mixed-use building 
was 48 [deg]F when heating. (NYSERDA, No. 21 at p. 3) NYSERDA commented 
that it had collected data supporting that the average building 
consistently uses EWTs of 55 [deg]F or lower and presented these data 
in a table that suggested the current EWT test condition of 68 [deg]F 
is unrepresentatively high. (Id. at pp. 3-4)
    In response to WaterFurnace's comment that some products cannot 
operate below 60 [deg]F, DOE notes that the heating temperatures in 
section 6.2.1 of AHRI 600-2023 include temperatures below 60 [deg]F, at 
50 [deg]F and 32 [deg]F. Inclusion of these EWTs in the updated 
industry standard suggests that there is industry agreement that WSHPs 
can generally operate below 60 [deg]F. DOE is not aware of any WSHPs 
that cannot operate in heating mode at 50 [deg]F and notes that the 
issue was not raised in

[[Page 84206]]

AHRI 600 committee meetings after the August 2022 NOPR. As discussed 
earlier in this section, comments from other interested parties also 
supported the use of a lower temperature.
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023. Section 6.2.1 of AHRI 600-
2023 includes EWTs of 68 [deg]F, 50 [deg]F, and 32 [deg]F for measuring 
COP. Additionally included in section 6.4.5 of AHRI 600-2023 is a new 
metric, ACOP, which is only measured at 50 [deg]F. This new metric is 
similar to COP but includes provisions accounting for system pump 
power, which better accounts for total energy use of WSHPs and aligns 
with changes made to the cooling efficiency metric (see section III.F.3 
of this document for more details). Further, ACOP is included in 
section 7.1 of AHRI 600-2023 as a minimum requirement for published 
ratings. Therefore, ACOP, measured at 50 [deg]F, is the heating metric 
required for WSHPs according to AHRI 600-2023. Having been developed 
through an industry consensus process subsequent to the timing of the 
August 2022 NOPR comment period, DOE surmises that ACOP tested at an 
EWT of 50 [deg]F specified in AHRI 600-2023 represents the prevailing 
industry consensus regarding the most appropriate metric for measuring 
heating performance. Therefore, in this final rule, DOE is 
incorporating by reference sections 6.2.1 and 6.4.5 of AHRI 600-2023 
into appendix C1 adopting the ACOP metric, tested at an EWT of 50 
[deg]F.
    DOE notes that no heating EWT of 55 [deg]F is included in section 
6.2.1 of AHRI 600-2023 and, instead, Table 8 of the document maintains 
the same heating test temperatures as ISO 13256-1:1998 (68 [deg]F, 50 
[deg]F, and 32 [deg]F). Therefore, due to the lack of support of a test 
temperature at 55 [deg]F, the exclusion of that temperature in AHRI 
600-2023, and the support for aligning with ISO 13256-1:1998 test 
temperatures (which include 50 [deg]F), DOE is finalizing the ACOP 
metric based on a test at 50 [deg]F, consistent with AHRI 600-2023.
    As discussed, use of the amended test procedure in appendix C1 and 
rating to ACOP at 50 [deg]F are not required until the compliance date 
of amended standards denominated in terms of ACOP, should DOE adopt 
such standards. DOE is defining ``ACOP'' in 10 CFR 431.92 as the ratio 
of the heating capacity to the power input, including system pump 
power, for water-source heat pumps and that ACOP is expressed in watts 
per watt and determined according to appendix C1 of subpart F of part 
431.
    Because AHRI 600-2023 requires a heating test at 50 [deg]F, there 
is no need for an interpolation method to determine ACOP at an EWT 
different from the tested EWT, and, therefore, AHRI 600-2023 includes 
no such interpolation method for ACOP. Correspondingly, because DOE is 
incorporating by reference AHRI 600-2023 into appendix C1 to require a 
heating test be conducted at 50 [deg]F and to adopt the ACOP metric 
based on the same EWT, the COP interpolation method proposed in the 
August 2022 NOPR is no longer applicable. Therefore, DOE is not 
adopting an interpolation method for determining ACOP in this final 
rule.
3. Optional Representations
    In the August 2022 NOPR, DOE proposed provisions to allow for 
optional representations of EER conducted per the proposed test 
procedure (sections 2 through 4 and 7 of proposed appendix C1) at the 
full-load and part-load EWT conditions specified in Table 1 of ISO 
13256-1:1998 (i.e., full load tests at 86 [deg]F, 77 [deg]F, and 59 
[deg]F and part-load tests at 86 [deg]F, 68 [deg]F, and 59 [deg]F). 87 
FR 53302, 53314. Additionally, DOE proposed provisions to provide for 
optional representations of COP based on testing conducted per the 
proposed test procedure (sections 2 through 4 and 7 of proposed 
appendix C1) at the full-load and part-load EWT conditions specified in 
Table 2 of ISO 13256-1:1998 (i.e., 68 [deg]F, 50 [deg]F, 41 [deg]F, and 
32 [deg]F). Id. at 87 FR 53317.
    AHRI 600-2023 includes provisions allowing for optional 
representations of EER and COP in sections 6.3.12 and 6.4.7, 
respectively. Optional representations can be made at any of the 
cooling and heating full-load and part-load EWT conditions in Table 8 
of AHRI 600-2023. DOE notes that the AHRI 600-2023 includes new metrics 
applied energy efficiency ratio (``AEER'') and ACOP (see section 
III.E.2 of this final rule for more details about ACOP). Each of these 
metrics include a power adder representing system pumps and the adder 
for AEER also includes cooling tower power. DOE notes that AHRI 600-
2023 does not have provisions for optional representations of these 
metrics and instead requires them to be published. The optional 
representations of EER and COP allowed for by AHRI 600-2023 do not 
include the power adder for system pumps and cooling tower power.
    As discussed in section III.E.1 and III.E.2 of this final rule, DOE 
is incorporating by reference AHRI 600-2023 for IEER and ACOP into 
appendix C1 as the cooling and heating metrics for WSHPs. The IEER 
metric as determined according to AHRI 600-2023 includes a power adder 
for system pumps and cooling tower power. DOE notes that the metrics it 
is adopting are intended to best reflect WSHP performance, using 
representative EWTs and including power for all components that are 
needed for operation of WSHP systems in a representative application 
(i.e., external pumps and cooling towers). Optional representations of 
EER and COP are intended to provide more information to consumers 
across a range of temperature conditions such that performance can be 
assessed for specific applications. DOE is adopting the provisions for 
optional representations of EER and COP from sections 6.3.12 and 6.4.7 
from AHRI 600-2023 by incorporating by reference AHRI 600-2023 into 
appendix C1. These provisions allow optional representations to be made 
consistent with AHRI 600-2023 at full-load or part-load at any of the 
standard rating conditions for WSHPs (i.e., 86 [deg]F, 68 [deg]F, and 
50 [deg]F for cooling and 68 [deg]F, 50 [deg]F, and 32 [deg]F for 
heating). DOE notes that these temperatures vary slightly from the 
proposals in the August 2022 NOPR for optional representations, but 
represent the same intent of allowing for optional representations of a 
range of operating conditions. Having been developed through an 
industry consensus process subsequent to the timing of the August 2022 
NOPR comment period, DOE has determined that the EWTs specified in AHRI 
600-2023 represent the prevailing industry consensus regarding the most 
appropriate EWTs for optional performance test points.
4. Entering Air Conditions
    The current DOE WSHP test procedure references ISO 13256-1:1998, 
which specifies in Table 1 that EER is measured with entering air at 27 
[deg]C (80.6 [deg]F) dry-bulb temperature and 19 [deg]C (66.2 [deg]F) 
wet-bulb temperature and in Table 2 that COP is measured with entering 
air at 20 [deg]C (68 [deg]F) dry-bulb temperature and 15 [deg]C (59 
[deg]F) wet-bulb temperature.
    In the August 2022 NOPR, DOE proposed to use the entering air 
conditions in Table 6 of AHRI 340/360-2022, which specify that cooling 
tests are measured with entering air at 80 [deg]F dry-bulb temperature 
and 67 [deg]F wet-bulb temperature heating tests are measured with 
entering air at 70 [deg]F dry-bulb temperature and a maximum of 60 
[deg]F wet-bulb temperature. 87 FR 53302, 53318. DOE discussed in the 
August 2022 NOPR that the entering air conditions specified in AHRI 
340/360-2022 are similar to the conditions specified in ISO 13256-
1:1998 and ISO 13256-1:2021, differing for cooling by

[[Page 84207]]

0.6 [deg]F for dry-bulb temperature and 0.8 [deg]F for wet-bulb 
temperature and for heating by 2 [deg]F for dry-bulb temperature and 1 
[deg]F for wet-bulb temperature. Id. DOE surmised that these 
differences are likely due to the conditions in ISO 13256-1 (1998 and 
2021 versions) being specified in terms of degrees Celsius, whereas the 
conditions in AHRI 340/360-2022 are specified in degrees Fahrenheit. 
Id. DOE also noted that the entering air conditions specified in AHRI 
340/360-2022 are the same as in previous versions of AHRI 340/360, 
including AHRI 340/360-2007, which is referenced in the current DOE 
test procedure for CUAC/HP equipment. Id. Further, the most common 
application for WSHPs (and the application DOE understands that the 
WSHP industry is intending to represent via use of the IEER metric in 
AHRI 600) is commercial buildings, similar to CUAC/HP equipment. Id. 
Therefore, DOE tentatively determined in the August 2022 NOPR that the 
entering air conditions in AHRI 340/360-2022 are appropriately 
representative of the average conditions in which WSHPs operate in the 
field. Id.
    DOE requested comment on its proposal to specify use of the cooling 
entering air conditions from AHRI 340/360-2022 (i.e., 80 [deg]F dry-
bulb temperature and 67 [deg]F wet-bulb temperature) and the heating 
entering air conditions from AHRI 340/360-2022 (i.e., 70 [deg]F dry-
bulb temperature and a maximum of 60 [deg]F wet-bulb temperature). Id.
    In response to the August 2022 NOPR, ClimateMaster recommended that 
DOE keep the existing entering air temperature conditions for both 
heating and cooling tests from ISO 13256-1:1998 to avoid the 
requirement to test equipment under two separate certification 
programs. (ClimateMaster, No. 22 at p. 6) ClimateMaster stated that the 
use of 80.6 [deg]F and 66.2 [deg]F entering air conditions for cooling 
would be more conservative (i.e., result in lower efficiency ratings) 
than those at 80 [deg]F and 67 [deg]F as specified in AHRI 340/360-
2022. (Id.)
    WaterFurnace commented that adopting ISO 13256 and AHRI 600 would 
solve the issue of which entering air conditions to use. (WaterFurnace, 
No. 20 at p. 7) WaterFurnace further commented that DOE's proposal 
would essentially require all new testing due to the different entering 
air conditions. (Id.) WaterFurnace stated that the existing entering 
air conditions of AHRI/ISO 13256 could be used and would result in a 
more conservative performance prediction. (Id.)
    MIAQ commented that it generally agrees with DOE's proposal to 
adopt the entering air conditions in AHRI 340/360-2022. (MIAQ, No. 23 
at p. 5)
    As discussed, DOE is adopting provisions for determining IEER and 
ACOP by incorporating by reference AHRI 600-2023 into appendix C1. The 
entering air conditions in section 6.2.1 of AHRI 600-2023 align with 
the entering air conditions specified in AHRI 340/360-2022 (and 
therefore align with DOE's August 2022 NOPR proposal). DOE surmises 
that inclusion of the AHRI 340/360-2022 entering air conditions in AHRI 
600-2023 indicates industry consensus with these test conditions. 
Therefore, DOE is adopting provisions for determining IEER and ACOP 
consistent with AHRI 600-2023, including entering air conditions of 80 
[deg]F dry bulb and 67 [deg]F wet bulb for cooling tests and 70 [deg]F 
dry bulb and a maximum of 60 [deg]F wet bulb for heating tests, in this 
final rule, by incorporating by reference into appendix C1 section 
6.2.1 of AHRI 600-2023.

F. Test Method

1. Airflow and External Static Pressure
a. Fan Power Adjustment and Required Air External Static Pressures
    For ducted units, the current DOE WSHP test procedure, which 
incorporates by reference ISO 13256-1:1998, specifies a fan power 
adjustment calculation that does not account for fan power used for 
overcoming external resistance. As a result, the calculation of 
efficiency includes only the fan power required to overcome the 
internal resistance of the unit. In addition, ISO 13256-1:1998 does not 
specify ESP requirements for ducted equipment, instead allowing 
manufacturers to specify a rated ESP. In the August 2022 NOPR, DOE 
proposed provisions to reflect fan power to overcome a representative 
ESP when calculating efficiency for ducted units to account for the 
impacts of ESP typically encountered in the field. 87 FR 53302, 53321. 
DOE determined that, to best reflect field operation, ducted WSHPs 
should be tested with minimum ESPs, the power for overcoming ESP should 
be included in efficiency calculations, and all equipment should be 
tested with an ESP upper tolerance. Id. DOE determined that the method 
in AHRI 340/360-2022 is more representative of field energy use than 
the methods used in ISO 13256-1:1998 for WSHPs. Id. DOE proposed to 
adopt AHRI 340/360-2022 for WSHPs, including section 6.1.3.3 and Table 
7 of AHRI 340/360-2022, which specify minimum ESPs for ducted units, a 
tolerance on ESP of -0.00/+0.05 in H2O, and no fan power 
adjustment. Id. DOE requested comment on the proposal to adopt 
provisions from AHRI 340/360-2022 such that for ducted units testing 
would be conducted within tolerance of the AHRI 340/360-2022 minimum 
ESP requirements, and efficiency ratings would include the fan power 
measured to overcome the tested ESP. Id. at 87 FR 53322.
    In response to the August 2022 NOPR, ClimateMaster recommended that 
DOE keep the existing ISO 13256-1:1998 standard and develop an IEER 
rating per AHRI 600 that offers provisions for complying with the 
required minimum external pressure as given in AHRI 340/360-2022. 
(ClimateMaster, No. 22 at p. 6) ClimateMaster stated that there are 
multiple reasons why the current ISO 13256-1:1998 standard excludes 
external static pressure, including that the methodology was created to 
rate different motor options for varying static requirements in the 
market space, which is especially problematic with non-variable speed 
motors as they are limited in output capability over a narrow static 
range. (Id.) MIAQ recommended DOE reference the ESP requirements in the 
latest edition of ISO 13256-1. (MIAQ, No. 23 at p. 5) WaterFurnace 
commented that supporting ISO 13256 and AHRI 600 would solve the issue 
and that it believes the required information can be calculated from 
AHRI/ISO 13256 data without retesting. (WaterFurnace, No. 20 at p. 7) 
WaterFurnace additionally commented that the minimum ESP requirements 
specified in AHRI 340/360 are adequate for most commercial WSHPs 
because most are installed with common plenum returns with little to no 
return ductwork. (Id.)
    FHP recommended that instead of requiring testing at minimum ESP 
requirements, DOE develop a revised fan power adjustment that 
incorporates accurate fan efficiencies and allows testing at a range of 
ESPs but adjusts fan performance to reflect performance at the minimum 
ESPs specified in AHRI 340/360-2022. (FHP, No. 26 at pp. 3-4) FHP 
asserted that such a revised fan power adjustment would allow for 
variations in tested ESP to achieve rated airflow to account for 
limitations of the fan-motor combination and variation in manufacturing 
tolerances, while still ensuring ratings are based on an ESP more 
representative than zero ESP. (Id.)
    The Joint Commenters supported DOE's proposal that WSHPs be tested 
at the ESPs specified in the proposed test procedure. (Joint 
Commenters, No. 27 at p. 2) The Joint Commenters stated that 
maintaining the current test procedure,

[[Page 84208]]

which applies a correction factor that adjusts fan power measured at 
the manufacturer-specified ESP is adjusted down to reflect fan power at 
zero ESP and incentivizes testing with higher-than-representative ESPs, 
would be inconsistent with the recommendation in the ASRAC Fans and 
Blowers Working Group term sheet to capture fan energy more fully 
across commercial HVAC product categories. (Id.)
    NEEA supported DOE's proposal to include additional fan energy in 
the WSHP efficiency metric, but also encouraged DOE to consider 
increasing the proposed ESP requirements to be more representative of 
current industry practice. (NEEA, No. 25 at pp. 2-3) NEEA stated that 
during the 2015 CUAC/HP energy conservation standard ASRAC 
negotiations, DOE's energy use analysis used ESP values 2 to 3 times 
higher than the ESP requirements in the current test procedure because 
DOE found the values to be more realistic and representative of field 
conditions. (Id. at p. 3) NEEA further recommended that DOE consider 
aligning WSHP ESP requirements with the updated CUAC/HP ESP 
requirements when they are finalized by the ASRAC Working Group. (Id.)
    With regards to these comments, DOE notes that section 5.5.1 of 
AHRI 600-2023 includes ESPs to be used for testing for ducted units. 
The ESPs are equivalent to those outlined in AHRI 340/360-2022 for 
units less than 75,000 Btu/h cooling capacity, but the ESPs for units 
above 75,000 Btu/h cooling capacity (i.e., 0.75 in. H2O for 
units from 75,000 Btu/h to 134,000 Btu/h; 1.00 in. H2O for 
units from 135,000 Btu/h to 280,000 Btu/h; and 1.50 in. H2O 
for units greater than 280,000 Btu/h) are significantly higher than 
those in AHRI 340/360-2022 and align with the ESP requirements 
recommended in the ACUAC and ACUHP Working Group TP Term Sheet. (See 
Document No. 65 in Docket No. EERE-2022-BT-STD-0015) Section 5.7 of 
AHRI 600-2023 also includes a tolerance of ESP of -0.00/+0.05 in 
H2O and sections 6.3 and 6.4 of AHRI 600-2023 include no fan 
power adjustment. DOE notes also that the approach set forth in AHRI 
600-2023 is mostly consistent with the approach proposed in the August 
2022 NOPR, with the only difference being higher ESP requirements for 
units greater than 75,000 Btu/h in cooling capacity. DOE has determined 
that the inclusion of ESP requirements, an ESP tolerance, and no fan 
power adjustment in AHRI 600-2023 represents industry consensus that 
these provisions provide the most appropriate and representative method 
for testing WSHPs. As discussed in section III.D of this final rule, 
DOE is incorporating by reference AHRI 600-2023 into appendix C1, 
including these ESP provisions. DOE notes that including these 
provisions is consistent with commenters' suggestions to adopt AHRI 
600.
    Regarding the higher ESP requirements for units with a cooling 
capacity greater than 75,000 Btu/h, adopting these values is consistent 
with NEEA's recommendation to align with the recommendations from the 
ASRAC Working Group for test procedures for CUAC/HPs. These ESP 
requirements were developed as part of a joint effort between 
manufacturers, efficiency advocates, utilities, and DOE to create a 
more representative efficiency metric for CUACs/HPs. DOE understands 
that WSHPs greater than 75,000 Btu/h are installed in similar 
applications to CUACs/HPs and, as such, DOE finds the AHRI 600-2023 ESP 
requirements to be representative for WSHPs with a cooling capacity 
greater than 75,000 Btu/h.
    DOE notes that the ACUAC and ACUHP Working Group TP Term Sheet 
recommends an ESP requirement of 0.75 in. H2O for units with 
a cooling capacity between 65,000 to 135,000 Btu/h, while the lower 
capacity limit for this requirement in section 5.5.1 of AHRI 600-2023 
is 75,000 Btu/h. Based on discussions in AHRI 600 committee meetings, 
DOE understands that there are WSHP model lines that span up to 6 tons 
that typically use fan/motor combinations that are designed for lower 
ESP applications and cannot operate at the rated airflow at an ESP as 
high as 0.75 in. H2O. Therefore, AHRI 600-2023 specifies a 
lower capacity limit for this ESP requirement of 75,000 Btu/h rather 
than 65,000 Btu/h so that these 6-ton models are tested with a more 
representative ESP. DOE understands this issue to be unique to WSHPs 
and does not apply to ACUACs and ACUHPs, for which models with a 
cooling capacity between 65,000 Btu/h and 75,000 Btu/h typically have 
different designs than three-phase ACUACs and ACUHPs (which typically 
have comparable designs to CAC/HPs) and are typically designed for 
installations for which an ESP of 0.75 in. H2O is 
representative. Therefore, in this final rule, DOE is incorporating by 
reference the requirements specified in Table 7 of section 5.5.1 of 
AHRI 600-2023 for all WSHPs with a cooling capacity less than 760,000 
Btu/h.
    With regard to comments from ClimateMaster and FHP expressing 
concern over ability of different fan/motor combinations to test at an 
ESP requirement at the rated airflow, DOE notes that this issue is 
addressed by the provisions for (1) non-standard high-static indoor fan 
motors and fan/motor combinations proposed in the August 2022 NOPR, 
included in section D4 of AHRI 600-2023 (discussed in section III.G.3 
of this final rule); and (2) non-standard low-static motors included in 
sections 3.2.30 and 5.7.4.3 of AHRI 600-2023 (discussed in section 
III.F.12 of this final rule). DOE has concluded that the inclusion of 
ESP requirements and provisions in AHRI 600-2023 for (1) non-standard 
high-static indoor fan motors and fan/motor combinations and (2) non-
standard low-static motors reflect industry consensus that these 
provisions provide an appropriate method for testing and rating WSHPs.
    DOE notes that section 5.5.1.2 of AHRI 600-2023 specifies a minimum 
ESP of 0.5 in. H2O for residential representations, but that 
the residential representations have not yet been fully developed for 
WSHPs (see section III.A.2 of this document for more details). DOE will 
continue to work with AHRI 600 committee to develop provisions for 
determining such ratings.
b. Setting Airflow and ESP
    DOE's current WSHP test procedure does not include provisions on 
how to simultaneously set airflow and ESP because there are no required 
ESPs for testing. Because DOE proposed to include minimum ESPs in its 
test procedure in the August 2022 NOPR, it also proposed provisions to 
address how to simultaneously set airflow and ESP. 87 FR 53302, 53322-
53324. The proposals were broken into three groups:
    (1) For ducted units with continuously variable speed fans, DOE 
proposed to use relevant provisions from AHRI 340/360-2022 in sections 
6.1.3.3 through 6.1.3.5.
    (2) For ducted units with discrete step fans, DOE proposed 
instructions for setting the fan speed in the scenario in which: (1) 
tolerances for airflow and ESP could not be met simultaneously, and (2) 
adjacent fan control settings result in airflow or ESP too low at the 
lower fan control setting and too high at the higher fan control 
setting.
    (3) For non-ducted units, DOE proposed units to be tested with a 
target ESP of 0.00 in H2O within a tolerance of -0.00/+0.05 
in H2O.

Id.

    For all three types of units, the proposed airflow tolerance was 3 
percent. Id.
    DOE requested comment on the proposed adoption of provisions from 
AHRI 340/360-2022 for setting airflow and ESP for testing WSHP units 
with

[[Page 84209]]

continuously variable speed fans. Id. at 87 FR 53323. DOE also 
requested comment on its proposed instructions (distinct from 
provisions in AHRI 340/360-2022) for setting airflow and ESP for ducted 
WSHP units with discrete-step fans. Id. Finally, DOE requested comment 
on its proposal for setting airflow and ESP for non-ducted WSHP units. 
Id. at 87 FR 53324.
    In response to the August 2022 NOPR, ClimateMaster recommended that 
DOE work with industry to create a national deviation of ISO 13256-
1:1998 that adopts the applicable parts of AHRI 340/360 for fully 
variable-speed motor systems and systems with adjustable sheaves, while 
still providing separate provisions for setting airflow for fan motor 
systems that are not continuously variable. (ClimateMaster, No. 22 at 
p. 7) ClimateMaster stated that it disagrees with the use of AHRI 340/
360-2022 for all indoor blower systems, arguing that these provisions 
were developed to accommodate only continuously variable-speed blower 
systems and asserted that the proposed 3 percent tolerance would not be 
feasible for larger WSHP systems without continuously variable motors 
or WSHPs with discrete-step or constant volume fan motors. (Id. at p. 
6) ClimateMaster stated that Table B1 of the AHRI WSHP Operations 
Manual \9\ specifies a 5 percent airflow tolerance for discrete-step 
motors. (Id. at p. 7) ClimateMaster further commented that the 
provisions for setting airflow in AHRI 210/240-2023 are more 
appropriate for the fan motors utilized in most WSHP systems (i.e., not 
continuously variable), stating that the AHRI 210/240-2023 provisions 
use manufacturer-specified fan motor settings and allow airflow to 
decrease to 10 percent below the target airflow. (Id. at p. 7)
---------------------------------------------------------------------------

    \9\ DOE notes that the AHRI WSHP Certification Operations Manual 
is available at: https://www.ahrinet.org/sites/default/files/2022-06/WSHP_OM.pdf (Last accessed April 25, 2023).
---------------------------------------------------------------------------

    FHP commented that the combination of a minimum ESP requirement and 
a 3 percent airflow tolerance would require additional testing and 
significant design constraints and changes at the component level for 
WSHPs with direct-drive motors and questioned whether a 3 percent 
airflow tolerance at a minimum ESP requirement is technologically 
feasible. (FHP, No. 26 at p. 4) FHP further commented that units with 
constant-torque direct-drive fan motors (e.g., permanent split 
capacitor (``PSC'') motors, electrically commutated motors (``ECMs'')) 
do not allow for adjustments to airflow without adjustments to ESP, 
making it difficult to consistently hit the airflow target within 3 
percent. (Id.) FHP also noted that the AHRI WSHP Operations Manual 
allows for adjustments to ESP to meet a 5-percent airflow tolerance for 
these systems. (Id.)
    WaterFurnace commented that adopting ISO 13256 and AHRI 600 would 
solve the issue. (WaterFurnace, No. 20 at p. 8) WaterFurnace stated 
that a test procedure for models fans with ECMs would have to be added 
to AHRI 340/360 because the standard does not address setting airflow 
and ESP for such models, which it stated are typical for smaller WSHPs. 
(Id.) MIAQ recommended DOE reference the latest edition of ISO 13256-1, 
stating that this standard is the industry test procedure currently 
used by manufacturers and laboratories for WSHP testing. (MIAQ, No. 23 
at p. 5)
    ClimateMaster stated that the WSHP Operations Manual covers 
available provisions with what they consider to be a proper allowance 
for airflow variation and that non-ducted WSHPs are available with 
motors that have multiple set speeds either through software or by 
utilizing a tapped motor winding. (ClimateMaster, No. 22 at p. 7) 
ClimateMaster stated that these provisions are slightly different from 
those proposed in the August 2022 NOPR and requested further 
clarification to the meaning of ``as close as possible''. (Id.) 
ClimateMaster noted that they expect that the speed tap specified by 
the manufacturer would be utilized and that, if this is the case, then 
there should not be any concern if the airflow is ``as close as 
possible'' to the rated point. (Id.)
    In response to the comment from ClimateMaster, DOE notes that the 
``as close to the target as possible'' language in the August 2022 NOPR 
is used in situations when the airflow and ESP requirements cannot be 
simultaneously met. Specifically, for non-ducted units, the August 2022 
NOPR provisions specify that if airflow and ESP requirements cannot be 
met simultaneously, the ESP requirement takes precedence (i.e., ESP 
must be maintained within tolerance) and the airflow is maintained as 
close as possible to the target airflow (but outside of tolerance). 
Section 5.8 of AHRI 600-2023 similarly specifies that in this situation 
the ESP must be maintained within tolerance and that there is no 
condition tolerance for airflow.
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes sections 5.7 and 5.8 of AHRI 600-2023. This language includes 
provisions generally consistent with provisions outlined in the August 
2022 NOPR, specifically a tolerance of 3 percent for setting airflow, 
separate provisions for continuously variable speed fans and discrete-
step fans, and a method for non-ducted units. Section 5.7 of AHRI 600-
2023 also includes provisions for setting airflow and ESP for constant-
volume fans, but DOE notes that these provisions were not proposed in 
the August 2022 NOPR and are consistent with provisions in appendix M1 
for central air conditioners and heat pumps.
    Regarding commenter's concerns about models with non-continuously-
variable fan motors, the comments received suggest that the commenters 
interpreted DOE's proposal to be adopting the provisions for setting 
airflow and ESP in AHRI 340/360-2022 without modification. However, as 
discussed in the August 2022 NOPR, DOE proposed additional provisions 
to allow a larger airflow tolerance for models with non-continuously-
variable fan motors that align more closely with the provisions for 
setting airflow in AHRI 210/240-2023 (as recommended by ClimateMaster). 
See 87 FR 53302, 53323. Similar provisions are included in AHRI 600-
2023. DOE has concluded that these provisions, along with the 
previously mentioned provisions for constant-volume fans, provide an 
appropriate method for setting airflow and ESP for WSHPs of all fan 
motor types.
    DOE has determined that incorporating by reference AHRI 600-2023 
for setting airflow and ESP addresses commenters' concerns. DOE 
surmises that the inclusion of these provisions for setting airflow and 
ESP in AHRI 600-2023 indicates industry consensus that these provisions 
provide an appropriate method for testing WSHPs. Therefore, in this 
final rule, DOE is incorporating by reference into appendix C1 sections 
5.7 and 5.8 of AHRI 600-2023 for setting airflow and ESP.
c. Coil-Only Units
    For units without integral fans (i.e., coil-only units), section 
4.1.3.1 of ISO 13256-1:1998, which is referenced in the current DOE 
WSHP test procedure, specifies that a fan power adjustment be added to 
the total power of the unit, and that this value be added to the 
heating capacity and subtracted from the cooling capacity. The fan 
power adjustment equation to determine fan power estimates fan power to 
overcome internal pressure drop within the unit, using a similar 
methodology to the fan power adjustment equation used for

[[Page 84210]]

units with integral fans to subtract out the fan power to overcome ESP. 
As discussed in section III.F.1.a of this final rule, the amended test 
procedure adopted in appendix C1 (incorporating by reference AHRI 600-
2023) does not use a fan power adjustment for units with integral fans 
and requires testing at representative minimum external static 
pressures and ratings reflect performance at the tested ESP.
    As part of DOE's proposal to adopt AHRI 340/360-2022, in the August 
2022 NOPR, DOE proposed to adopt sections 6.1.1.6, 6.1.3.3 and 6.1.3.4 
of AHRI 340/360-2022, which contain provisions for how to test coil-
only units. 87 FR 53302, 53322. In particular, section 6.1.3.3.4 
specifies that coil-only units shall not have a pressure drop exceeding 
0.30 in H2O for the full load cooling test. Section 
6.1.3.4.6 outlines that coil-only units are to be tested at 
manufacturer specified airflow rates, not exceeding 450 standard cubic 
feet per minute (``scfm'') per ton of cooling capacity and if there is 
no manufacturer specified airflow rate, they are to be tested at 400 
scfm per ton of rated cooling capacity. Finally, section 6.1.1.6 
specifies that 1,250 Btu/h per 1,000 scfm is to be removed from the 
measured cooling capacity and 365 Watts (``W'') per 1,000 scfm is to be 
added to the measured power for ducted coil-only units.
    AHRI 600-2023 includes provisions for coil-only units, which are 
defined as units without an indoor fan or separate designated air 
mover. The provisions are nearly identical to those proposed in the 
August 2022 NOPR. Section 5.5.2 specifies that coil-only units shall 
not have a pressure drop exceeding 0.30 in H2O for the full-
load cooling test. Section 5.6.3 outlines that coil-only units are to 
be tested at manufacturer specified airflow rates, not exceeding 450 
scfm per ton of cooling capacity and if there is no manufacturer 
specified airflow rate, they are to be tested at 400 scfm per ton of 
rated cooling capacity. Finally, sections 6.3.3.4 and 6.4.3.4 specify 
that for ducted coil-only units, measured capacity is adjusted by 1,245 
Btu/h per 1,000 scfm (subtracted from cooling capacity and added to 
heating capacity) and measured power is adjusted by adding 365 W per 
1,000 scfm. Additionally, AHRI 600-2023 includes provisions for non-
ducted coil only units--for these, the values are 940 Btu/h per 1,000 
scfm for capacity adjustment and 275 W per 1,000 scfm for power adder 
respectively.
    DOE notes that the provisions outlined in AHRI 600-2023 are 
consistent with those proposed in the August 2022 NOPR except for a 
minor deviation in the capacity reduction for ducted coil-only units 
and the inclusion of provisions for non-ducted coil-only units. Based 
on discussion in AHRI 600 committee meetings, DOE understands that non-
ducted coil-only WSHP models exist on the market, and therefore, DOE 
has determined that the addition of provisions for testing such units 
is warranted. As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 5.5.2, 5.6.3, and 6.3.3.4 of AHRI 600-2023. DOE notes 
the inclusion of these provisions in AHRI 600-2023 indicates industry 
consensus with these provisions and provides an appropriate method for 
testing coil-only WSHPs. Therefore, DOE is incorporating by reference 
into appendix C1 the provisions for coil-only units from AHRI 600-2023 
in this final rule.
2. Capacity Measurement
    The current DOE WSHP test procedure, through adoption of section 
6.1 of ISO 13256-1:1998, specifies that total cooling and heating 
capacities are to be determined by averaging the results obtained using 
two test methods: the liquid enthalpy test method for the liquid side 
tests and the indoor air enthalpy test method for the air side tests. 
10 CFR 431.96. For non-ducted equipment, section 6.1 of ISO 13256-
1:1998 includes an option for conducting the air-side tests using the 
calorimeter room test method instead of the air enthalpy test method. 
Section 6.1 of ISO 13256-1:1998 also specifies that, for a test to be 
valid, the results obtained by the two methods used must agree within 5 
percent. ANSI/ASHRAE 37-2009 is similar to the test method in ISO 
13256-1:1998. ANSI/ASHRAE 37-2009 requires two capacity measurements 
for units with cooling capacity less than 135,000 Btu/h; the first 
method of measurement (i.e., the primary method) is used as the 
determination of the unit's capacity, while the second measurement 
(i.e., the secondary method) is used to confirm rather than to be 
averaged with the primary measurement (see section 10.1 and Table 1 of 
ANSI/ASHRAE 37-2009).
    In the August 2022 NOPR, DOE proposed to adopt specific sections of 
AHRI 340/360-2022 for use in the WSHP test procedure, including section 
E6, which specifies test methods for capacity measurement. 87 FR 53302, 
53325-53327. Section E6.1 of AHRI 340/360-2022 requires use of the 
indoor air enthalpy method specified in section 7.3 of ANSI/ASHRAE 37-
2009 as the primary method for capacity measurement. This is the 
measurement used to determine capacity, as required in section 10.1.2 
of ANSI/ASHRAE 37-2009. Section E6.2.2 of AHRI 340/360-2022 requires 
use of one of the applicable ``Group B'' methods specified in Table 1 
of ANSI/ASHRAE 37-2009 as a secondary method for capacity measurement. 
The group B methods that are applicable to WSHPs are the outdoor liquid 
coil method (similar to the liquid enthalpy method included in the 1998 
and 2021 versions of ISO 13256-1), the refrigerant enthalpy method, and 
the compressor calibration method. Section E6.4.2 of AHRI 340/360-2022 
requires that the primary and secondary measurements match for full-
load cooling and heating tests, within 6 percent of the primary 
measurement. No match is required between primary and secondary 
measurements for part-load cooling tests. DOE proposed to adopt all of 
these provisions by incorporating by reference AHRI 340/360-2022. Id. 
at 87 FR 53325. DOE requested comment on this approach to adopt the 
provisions in AHRI 340/360-2022 and ANSI/ASHRAE 37-2009 regarding 
primary and secondary capacity measurements. Id. at 87 FR 53326.
    In response to the August 2022 NOPR, ClimateMaster commented that 
it agrees with the intent of DOE's proposed approach but disagrees with 
some specifics and recommended that DOE work with industry to create a 
national deviation of ISO 13256-1:1998 that adopts the provisions of 
ANSI/ASHRAE 37-2009 for primary and secondary capacity measurements, 
with certain modifications. (ClimateMaster, No. 22 at pp. 7-8) 
ClimateMaster commented additionally that it disagrees with the 
provisions in AHRI 340/360-2022 that only require agreement between the 
primary and secondary capacity measurements for full-load tests. (Id. 
at p. 8) ClimateMaster noted that the current ISO standard allows for a 
5 percent tolerance between the two measurements, and that in its 
internal testing ClimateMaster strives for agreement within 3-4 
percent, stating that anything over that limit indicates an issue in 
equipment setup and/or the measurement system. (Id.) ClimateMaster 
commented that neglecting to include a match requirement for part-load 
tests could lead to inaccurate representations of system performance. 
(Id.)
    ClimateMaster further commented that the uncertainty of measurement 
for the liquid coil method is lower than for the indoor air enthalpy 
method, and that the WSHP industry considers the liquid coil method to 
be the more accurate measurement method. (Id.) ClimateMaster also 
stated that the liquid coil method does not include the

[[Page 84211]]

limitations regarding refrigerant sub-cooling that are specified for 
the refrigerant enthalpy method (in section 7.5.1.3 of ANSI/ASHRAE 37-
2009), and stated that low values of refrigerant subcooling are 
typically seen in part-load tests. (Id.) ClimateMaster commented that 
it disagrees with section 7.6.1.2 of ANSI/ASHRAE 37-2009 because this 
provision specifies that the outdoor liquid coil method cannot be used 
for outdoor compressor systems, and therefore makes the refrigerant 
enthalpy method necessary as the secondary capacity measurement method 
for such systems. (Id.) ClimateMaster stated that while it agrees in 
theory that the compressor and associated refrigerant lines will lose 
heat when an uninsulated compressor section is installed outdoors, 
requiring the use of the refrigerant enthalpy method is not 
representative of installed outdoor compressor systems because for 
testing the outdoor section of a split WSHP system is installed in the 
same psychrometric room as the indoor air handler. (Id.) ClimateMaster 
added that there are currently no specified outdoor conditions or 
requirements for placement of the outdoor unit in a differently 
conditioned room and that the difference between the current liquid 
coil method and the proposed refrigerant enthalpy method is negligible 
without specifying conditions more thoroughly. (Id.) ClimateMaster 
further commented that the insulation requirements in ANSI/ASHRAE 37-
2009 only specify 1 inch of fiberglass insulation and do not specify a 
minimum R-value for the insulation. (Id.)
    In summary, ClimateMaster recommended that DOE adopt the indoor air 
enthalpy method for the primary capacity measurement, and that the 
outdoor coil liquid method be used for the secondary capacity 
measurement if the unit either (1) meets the requirements of section 
7.6.1.2 of ANSI/ASHRAE 37-2009 using fiberglass insulation or an 
equivalent material with an R-value of 8.0, or (2) is an outdoor unit 
installed in the same test chamber as the indoor coil. (Id.) 
ClimateMaster further recommended a requirement for agreement within 5 
percent between primary and secondary capacity measurements for full-
load and part-load tests. (Id.)
    MIAQ commented that DOE's proposed approach in the August 2022 NOPR 
of adopting the provisions in AHRI 340/360 and ANSI/ASHRAE 37-2009 
regarding primary and secondary capacity measurements deviates from the 
industry test procedure ISO 13256-1 and therefore will require 
manufactures to retest their products, resulting in increased burden. 
(MIAQ, No. 23 at p. 6)
    WaterFurnace commented that adopting ISO 13256 and AHRI 600 would 
solve the issue and that the liquid enthalpy test method is widely 
accepted as the most accurate method for capacity measurement for 
WSHPs. (WaterFurnace, No. 20 at p. 8)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into Appendix C1, including 
provisions in Section 5.2 of AHRI 600-2023 regarding primary and 
secondary capacity measurement methods. Specifically, Section 5.2 
states that the indoor air enthalpy method be used as the primary 
measurement of capacity, and that secondary capacity measurements be 
conducting using one of the following methods: outdoor liquid coil 
method, refrigerant enthalpy method, or compressor calibration method. 
Section 5.2.2 of AHRI 600-2023 also states that, when using the outdoor 
liquid coil method, the secondary measurement must agree within 6 
percent of the primary measurement of capacity on all tests, including 
part-load tests. Incorporating by reference this language addresses 
comments in response to the August 2022 NOPR that DOE should adopt AHRI 
600. The provisions in AHRI 600-2023 also address ClimateMaster's 
concerns about not having a match for part-load tests because AHRI 600-
2023 does require a match between primary and secondary capacity 
measurements for part-load tests if the outdoor liquid coil method is 
used.
    Regarding agreement between primary and secondary measurements, DOE 
has concluded that the requirement in AHRI 600-2023 that secondary 
capacity measurements agree within 6 percent of primary capacity 
measurements (consistent with AHRI 340/360-2022, which DOE proposed to 
reference in the August 2022 NOPR) provides a representative measure of 
efficiency for WSHPs.
    Regarding ClimateMaster's concerns about the outdoor liquid coil 
method provisions in ANSI/ASHRAE 37-2009, DOE notes that section 
5.2.2.1.1 of AHRI 600-2023 specifies to follow all requirements in 
section 7.6 of ANSI/ASHRAE 37-2009 when using the outdoor liquid coil 
method and does not include any provisions that deviate from ANSI/
ASHRAE 37-2009 with regard to outdoor compressor systems or insulation 
R-value. Regarding ClimateMaster's concern that ANSI/ASHRAE 37-2009 
requires use of the refrigerant enthalpy method for secondary capacity 
measurements for systems in which the compressor is located outdoors, 
DOE further notes that for a split system WSHP with the compressor and 
liquid coil contained in the outdoor unit intended for outdoor 
installation, shell losses from the compressor could impact capacity 
measurements using the outdoor liquid coil method but would not impact 
capacity measurements using the refrigerant enthalpy method. Therefore, 
at this time, DOE does not have sufficient evidence or justification to 
deviate from the provisions in AHRI 600-2023 regarding the outdoor 
liquid coil method and has concluded that these provisions provide for 
appropriate and representative measurements of efficiency for WSHPs.
    Additionally, AHRI 600-2023 was developed through an industry 
consensus process subsequent to the timing of the August 2022 NOPR 
comment period, and DOE surmises that the capacity measurement approach 
specified in section 5.2 of AHRI 600-2023 sufficiently addresses the 
concerns raised in comments to the August 2022 NOPR. Consequently, DOE 
is incorporating by reference into appendix C1 section 5.2 of AHRI 600-
2023 regarding primary and secondary capacity measurements in this 
final rule.
3. Pump Power Adjustment and Liquid External Static Pressure
    ISO 13256-1:1998 does not reflect the pump power needed to overcome 
liquid ESP from the water loop that pipes water to and from the WSHP. 
Instead, section 4.1.4 of ISO 13256-1:1998 includes a pump power 
adjustment (which assumes a pump efficiency of 0.3 for all units) to be 
applied such that only the pump power required to overcome the liquid 
internal static pressure of the unit is included in calculation of 
efficiency ratings. ISO 13256-1:1998 also does not specify any liquid 
ESP requirements for testing. The exclusion of pump power to overcome 
ESP from system water loop piping in ISO 13256-1:1998 ratings results 
in higher efficiency ratings than would be measured if ratings 
reflected pump power to overcome ESP. ISO 13256-1:1998 also does not 
specify a minimum liquid ESP during testing for units with integral 
pumps. For units without integral pumps, the pump power adjustment in 
ISO 13256-1:1998 estimates pump power at zero liquid external static 
pressure.
    As discussed previously, ISO 13256-1:1998 was updated. However, the 
pump power and liquid ESP provisions in sections 5.1.4 and 5.1.6 of ISO

[[Page 84212]]

13256-1:2021 are the same as those in sections 4.1.4 and 4.1.6 of ISO 
13256-1:1998.
    In the August 2022 NOPR, DOE proposed to adopt provisions for WSHPs 
in appendix C1 that align with the recently adopted provisions for 
water-source dedicated outdoor air systems (``DOASes''). 87 FR 53302, 
53328-53329. The proposed provisions would require that all WSHPs with 
an integral pump be tested with a liquid ESP of 20 ft of water column, 
with a -0/+1 ft condition tolerance and a 1 ft operating tolerance. Id. 
at 87 FR 53328. For units without integral pumps, DOE proposed to 
require that a ``total pumping effect'' (calculated using the same 
equation as in section 6.1.6.4 of AHRI 920-2020) be added to the unit's 
measured power to account for the pump power to overcome the internal 
static pressure of the unit and a liquid ESP of 20 ft of water column. 
Id. at 87 FR 53328-53329. Further, DOE proposed to require that the 
measured pump power or the pump effect addition, as applicable, be 
included in the condenser section power for units of all capacities 
when performing cyclic degradation during calculation of IEER. Id. at 
87 FR 53329. DOE requested commented on the proposed provisions to 
account for pump power to overcome both internal pressure drop and a 
representative level of liquid ESP for WSHPs with and without integral 
pumps. Id. DOE specifically requested comment on the representativeness 
of 20 ft of water column as the liquid ESP for WSHPs. Id.
    In response to the August 20222 NOPR, ClimateMaster disagreed with 
DOE's proposed values for the liquid ESP for WSHPs, arguing that the 
pumping and cooling tower fan power adder specified in AHRI 920-2020 is 
incorrect. (ClimateMaster, No. 22 at p. 8) ClimateMaster commented 
that, according to a 2014 study conducted by S. Kavanaugh and K. 
Rafferty, pumping power for a closed loop ground-source heat pump 
(``GSHP'') system can reach 3.75 W/kBtu/h but not exceed 10 W/1kBtu/h, 
and that the values given in AHRI 920 are much higher than these values 
and are thus not representative of an installed system. (Id. at pp. 8-
9) ClimateMaster recommended that DOE use the approach in AHRI 600, 
which includes pumping power for the internal pressure drop and adds a 
representative value for building pump and cooling tower operation. 
(Id. at p. 9) ClimateMaster commented that this AHRI 600 power adder 
for building pump and cooling tower energy consumption is based on the 
results of an analysis conducted of typical closed loop systems during 
the development of the AHRI 600 standard, which resulted in calculated 
power adders of 5.5 W/kBtu/h for full-load conditions and 1 W/kBtu/h 
for part-load conditions. (Id.)
    FHP commented that the work done by the AHRI 600 working group took 
a more accurate approach to today's systems that allows for varying the 
fans and pumping energy required during part-load conditions. (FHP, No. 
26 at p. 5) FHP recommended that DOE review the values assigned to 
tower/pump penalty in AHRI 600 for guidance on this topic, stating that 
a single-head pressure as a means of estimating the pumping penalty 
does not allow for the variations expected at part-load conditions. 
(Id.) WaterFurnace commented that adopting ISO 13256 and AHRI 600 would 
solve the issue, noting that the pump power is accounted for in AHRI 
600. (WaterFurnace, No. 20 at p.8)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. AHRI 600-
2023 includes provisions to separately account for pump power to 
overcome liquid internal and external static pressure.
    Sections 6.3.3 and 6.4.3 of AHRI 600-2023 specify to include pump 
power to overcome the liquid internal static pressure of the WSHP in 
all cooling and heating ratings. The calculation for pump power 
adjustment to account for liquid internal static pressure uses a 
similar methodology to ISO 13256-1:1998, but uses a higher pump 
efficiency of 75% (as compared to 30% in ISO 13256-1:1998) to better 
represent the efficiency of system pumps in commercial water-loop 
installations. Specifically, for units without integral pumps, the AHRI 
600-2023 approach adds pump power to overcome liquid internal static 
pressure. For units with integral pumps, section 5.4.13 of AHRI 600-
2023 specifies a liquid ESP value of zero to use when testing WSHPs 
with an integral pump for commercial ratings and specifies to test at 
the minimum liquid ESP if the minimum is higher than zero ESP. In the 
case of testing a unit with an integral pump at a liquid ESP above 
zero, sections 6.3.3 and 6.4.3 of AHRI 600-2023 specify to subtract 
pump power to overcome liquid ESP using a similar methodology to the 
approach for calculating pump power adjustment for units without 
integral pumps.
    Sections 6.3.7 (for IEER), 6.3.11 (for AEER), and 6.4.4 (for ACOP) 
of AHRI 600-2023 specify to include power to account for power required 
for a system pump to overcome liquid ESP representative of a commercial 
water-loop installations. As discussed in section III.E.3 of this final 
rule, AHRI 600-2023 specifies these provisions to account for system 
pump power for calculation of AEER, IEER, and ACOP, but not for 
optional representations of EER and COP.
    The provisions for accounting for pump power (to overcome liquid 
internal and external static pressure) were developed in AHRI 600 
committee meetings after publication of the August 2022 NOPR. While the 
AHRI 600-2023 approach is not the same as that proposed in the August 
2022 NOPR in that it uses a different calculation method and assumes a 
different liquid ESP, it is consistent with the August 2022 NOPR 
proposal to include power to represent power consumed by pumps to 
overcome both liquid internal and external static pressure. The AHRI 
600-2023 pump power adders are different than those suggested by 
ClimateMaster. However, having been developed through an industry 
consensus process subsequent to the timing of the August 2022 NOPR 
comment period, DOE surmises that the pump power approach specified in 
AHRI 600-2023 represents the prevailing industry consensus regarding 
the most appropriate method for addressing pump power. Further, DOE has 
concluded based on discussion in AHRI 600 committee meetings that the 
AHRI 600-2023 pump power approach is representative of typical water-
loop WSHP applications. As a result, in this final rule, DOE is 
incorporating by reference into appendix C1 the methods specified in 
AHRI 600-2023 for accounting for pump power.
    DOE notes that section 5.4.13.2 of AHRI 600-2023 specifies a 
minimum liquid ESP of 7.0 psi for residential representations. However, 
the residential representations have not yet been fully developed for 
WSHPs (see section III.A.2 of this document for more details). DOE will 
continue to work with the AHRI 600 committee to develop provisions for 
determining such ratings.
4. Test Liquid and Specific Heat Capacity
    The current DOE WSHP test procedure, through adoption of section 
4.1.9 of ISO 13256-1:1998, requires the test liquid for water-loop heat 
pumps and ground-water heat pumps to be water, and the test liquid for 
ground-loop heat pumps to be a 15 percent solution by mass of sodium 
chloride in water (i.e., brine). 10 CFR 431.96. Further, the liquid 
enthalpy test method in Annex C of ISO 13256-1:1998, which is included 
in the current DOE WSHP test procedure, requires the use of the

[[Page 84213]]

specific heat capacity of the test liquid for calculating cooling and 
heating capacity but does not specify a value or method for calculating 
the specific heat capacity.
    Section 5.1.7 of ISO 13256-1:2021 requires that the test liquid for 
the low temperature heating test (i.e., EWT of 32 [deg]F) must be a 
brine of the manufacturer's specification, while the test liquid for 
all other tests may be water or a brine of a composition and 
concentration specified by the manufacturer. ISO 13256-1:2021 does not 
specify a value or method for calculating the specific heat capacity of 
any test liquids.
    In the August 2022 NOPR, DOE proposed in section 4.1 of proposed 
appendix C1 that the test liquid for all tests other than the proposed 
optional ``HFL3'' \10\ low temperature heating test (i.e., EWT of 32 
[deg]F) must be water, unless the manufacturer specifies to use a brine 
of 15-percent solution by mass of sodium chloride in water. 87 FR 
53302, 53329. DOE also proposed in section 4.1 of proposed appendix C1 
that the test liquid for the optional HFL3 low temperature heating test 
must be a brine of 15-percent solution by mass of sodium chloride in 
water. Id. Ground-loop applications of WSHPs typically use brine in the 
liquid loop because, in cold weather, the liquid temperature can reach 
32 [deg]F (i.e., the temperature at which water freezes) in places. A 
15-percent solution by mass of sodium chloride in water can withstand 
temperatures as low as 14 [deg]F before freezing. Allowing the use of 
brine for testing would provide manufacturers the flexibility of 
providing ratings more representative of ground-loop applications. 
Therefore, DOE proposed to require brine as the liquid for the optional 
HFL3 low temperature heating test (conducted with an EWT of 32 [deg]F), 
consistent with section 4.1.9 of ISO 13256-1:1998 and section 5.1.7 of 
ISO 13256-1:2021, to avoid the liquid freezing during the test. Id.
---------------------------------------------------------------------------

    \10\ ``HFL3'' is the nomenclature used to define the 32 [deg]F 
full-load heating test that DOE proposed to add in appendix C1.
---------------------------------------------------------------------------

    In the August 2022 NOPR, DOE tentatively concluded that a 15-
percent solution by mass of sodium chloride, as specified in section 
4.1.9.2 of ISO 13256-1:1998, is a representative brine composition and 
concentration for applications needing brine (e.g., ground-loop), and 
that consumers can make more representative comparisons between models 
when all models are rated with the same brine composition and 
concentration. Id.
    As discussed in section III.D.2 of the August 2022 NOPR, DOE 
proposed to adopt specific sections of AHRI 340/360-2022 in its test 
procedure for WSHPs. Id. AHRI 340/360-2022 in turn references the test 
method in ANSI/ASHRAE 37-2009, in which section 12.2.1 requires that 
thermodynamic properties of liquids be obtained from the ASHRAE 
Handbook--Fundamentals.\11\ The ASHRAE Handbook--Fundamentals specifies 
specific heat capacity values for water and for a brine of 15 percent 
solution by mass of sodium chloride at multiple temperatures. The 
absence of provisions in ISO 13256-1:1998 for how to determine specific 
heat capacity for test liquids creates the potential for variation in 
measured values based on how specific heat capacity is determined. 
Therefore, to minimize any such variation, DOE instead proposed in the 
August 2022 NOPR to adopt relevant provisions of ANSI/ASHRAE 37-2009. 
Id. DOE tentatively determined that the specifications in ANSI/ASHRAE 
37-2009 would be appropriate for testing WSHPs because they are the 
generally accepted industry method used for testing similar equipment, 
such as WCUACs. Id.
---------------------------------------------------------------------------

    \11\ The ASHRAE Handbook--Fundamentals is available at: https://www.ashrae.org/technical-resources/ashrae-handbook.
---------------------------------------------------------------------------

    In the August 2022 NOPR, DOE requested comment on the proposed 
requirements for using water or a brine of 15-percent solution by mass 
of sodium chloride as the test liquid. Id. DOE also requested comment 
on the representativeness and test burden associated with permitting 
the use of different liquids for different tests. Id. Finally, DOE 
requested comments on the proposal to utilize the thermodynamic 
properties specified in ANSI/ASHRAE 37-2009 through DOE's proposed 
incorporation by reference of AHRI 340/360-2022. Id.
    In response to the August 2022 NOPR, MIAQ commented that sodium 
chloride is not a common anti-freeze and that propylene and ethylene 
glycol are more common. (MIAQ No. 23 at p. 6) MIAQ commented that it is 
unsure if nationally recognized testing laboratories \12\ are equipped 
to deal with 15-percent solution by mass of sodium chloride as the test 
liquid. (Id.) MIAQ stated that specifying a particular antifreeze 
rather than relevant thermal properties for the test fluid hinders 
innovation and generates a heavy burden to develop and test with the 
specified medium. (Id.) MIAQ argued that specifying sodium chloride as 
the test liquid may require redesign of the units to avoid corrosion. 
(Id.)
---------------------------------------------------------------------------

    \12\ MIAQ used the abbreviation NRL, but DOE expects that the 
intended term was NRTL, the acronym for nationally recognized 
testing laboratory.
---------------------------------------------------------------------------

    WaterFurnace commented that supporting ISO 13256 and AHRI 600 would 
solve the issue. (WaterFurnace No. 20 at p. 8) WaterFurnace stated that 
it prefers to use methanol or ethanol as the test liquid because sodium 
chloride can damage lab equipment. (Id.)
    ClimateMaster supported DOE's proposal to make provisions for low 
temperature testing but disagreed with the proposed fluid for testing. 
(ClimateMaster, No. 22 at p. 9) ClimateMaster stated that sodium 
chloride is not representative of a brine solution used in water-source 
applications in the field and is a carryover from a test liquid used in 
older standards such as AHRI 330-98, which was corrosive to test lab 
facilities and caused premature wear of hydronic components. (Id.) 
ClimateMaster recommended that DOE work with industry to create a 
national deviation of 13256-1:1998 that includes provisions for the use 
of a 15-percent solution by mass of methanol in water involving a 
specific gravity of methanol at 0.976 with a solution temperature of 68 
[deg]F. (Id.) ClimateMaster stated that this fluid is commonly used in 
the industry and has been an available option in the AHRI 13256-1:1998 
certification program since its inception, and if DOE does not select 
this solution, an alternative option would be a 20-percent solution of 
propylene glycol, which is also commonly used in the industry. (Id.)
    ClimateMaster supported DOE's proposal to require a standard set of 
properties for consistent performance calculations but disagreed that 
the only reference allowed for sink or source liquids can be the 2001 
ASHRAE Handbook, stating that it does not include properties for 
alternative testing fluids, such as methanol in water, and therefore 
limits the available options for testable brine solutions. (Id.) 
ClimateMaster recommended that DOE provide provisions under a national 
deviation of ISO 13256-1:1998 while allowing for the use of other 
established property databases in addition to the 2001 ASHRAE handbook, 
such as the published data from Melinder 2010.\13\ (Id.) WaterFurnace 
agreed with the need for a specified source of properties and commented 
that supporting ISO 13256

[[Page 84214]]

and AHRI 600 would solve the issue. (WaterFurnace, No. 20 at p. 8)
---------------------------------------------------------------------------

    \13\ Properties of Secondary Working Fluids for Indirect 
Systems, Melinder, 2010 (``Melinder 2010'').
---------------------------------------------------------------------------

    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 in appendix C1. Section 5.4.14 
of AHRI 600-2023 specifies that all cooling and heating tests be 
conducted with a 15 percent solution by mass of methanol in water, with 
a tolerance of 2 percentage points on the solution concentration and 
requires that the concentration be verified prior to and after 
completion of all standard rating tests. Section 5.4.14 of AHRI 600-
2023 also specifies to use Melinder 2010 as the source for all 
thermodynamic properties of the test liquid. Finally, sections 6.3.3.2 
and 6.4.3.2 of AHRI 600-2023 include provisions to remove any influence 
of the methanol solution on efficiency ratings, so that values are 
similar to those that would result from testing using pure water, which 
is the most common liquid used in non-geothermal installations of 
WSHPs. Specifically, these provisions specify to multiply all measured 
capacity values by 1.01 and to multiply all measured cooling total 
power values by 0.99.
    DOE has concluded that the provisions in AHRI 600-2023 regarding 
test liquid and specific heat capacity provide a representative and 
repeatable method for testing WSHPs. Comments received in response to 
the August 2022 NOPR and discussion in AHRI 600 committee meetings 
indicate that a methanol solution is a more representative test liquid 
than sodium chloride brine and is more practical for testing as it is 
not corrosive to laboratory equipment. Further, the AHRI 600-2023 
requirement to use methanol solution for all tests ensures repeatable 
results and minimizes test burden by avoiding a need to change test 
liquid between tests. By specifying use of Melinder 2010 as the source 
for thermodynamic properties, AHRI 600-2023 also ensures that 
thermodynamic properties for the test fluid are applied consistently. 
Additionally, the provisions in sections 6.3.3.2 and 6.4.3.2 of AHRI 
600-2023 adjust measured values to be more representative of WSHP 
operation in non-geothermal applications (which do not encounter 
freezing temperatures), without the need to change test liquids to use 
water for higher temperature tests and methanol for low-temperature 
heating tests. DOE also considers the inclusions of these provisions in 
AHRI 600-2023 to represent industry consensus on the most appropriate 
method for testing WSHPs. Therefore, for the reasons discussed, DOE is 
incorporating by reference into appendix C1 the test liquid provisions 
from AHRI 600-2023 in this final rule.
5. Liquid Flow Rate
    The current DOE test procedure, through adoption of section 4.1.6.2 
of ISO 13256-1:1998, requires units with an integral liquid pump to be 
tested at the liquid flow rates specified by the manufacturer or those 
obtained at zero ESP difference, whichever provides the lower liquid 
flow rate. 10 CFR 431.96. Section 4.1.6.3 of ISO 13256-1:1998 requires 
that units without an integral liquid pump be tested at a liquid flow 
rate specified by the manufacturer.
    In contrast to ISO 13256-1:1998, DOE noted in the June 2018 RFI 
that AHRI 340/360-2022 does not use a manufacturer-specified liquid 
flow rate, and instead specifies inlet and outlet water temperatures 
for WCUACs to be 85 [deg]F and 95 [deg]F, respectively, for standard-
rating full-capacity operation. The temperature difference between 
inlet and outlet determines the liquid flow rate for the test. 83 FR 
29048, 29054.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
specific sections of AHRI 340/360-2022 in its test procedure for WSHPs, 
including Table 6. 87 FR 53302, 53330. Table 6 of AHRI 340/360-2022 
specifies inlet and outlet liquid temperatures of 85 [deg]F and 95 
[deg]F, respectively, for standard-rating cooling full-capacity 
operation. Id. This requires that liquid flow rate for the full-load 
cooling test is set at a level that results in a 10 [deg]F temperature 
rise from the 85 [deg]F inlet to the 95 [deg]F outlet temperature. Id. 
Also, DOE proposed to adopt table 9 of AHRI 340/360-2022, which 
specifies use of manufacturer-specified part-load water flow rates for 
part-load tests. Id. at 87 FR 53331. In addition, DOE proposed that 
section E7 of AHRI 340/360 2022, which addresses units with condenser 
head pressure control stating that part-load liquid flow rate shall not 
exceed the liquid flow rate used for the full-load tests, be adopted in 
sections 5.1.1 and 5.1.2.1.2 of proposed appendix C1. Id. For heating 
tests, DOE proposed to specify in section 6.1 of proposed appendix C1 
that if IEER is determined using option 1 in section 5.1 of proposed 
appendix C1, the liquid flow rate determined from the ``Standard Rating 
Conditions Cooling'' test for water-cooled equipment, as defined in 
Table 6 of AHRI 340/360-2022, must be used for all heating tests. Id. 
If IEER is determined using option 2 in section 5.1 of proposed 
appendix C1, DOE proposed in section 5.1.2.1.1 of proposed appendix C1 
to use the liquid flow rate determined from the CFL3 high temperature 
cooling test for all heating tests. Id. Lastly, relating to tolerances, 
DOE proposed to require a condition tolerance of 1 percent for liquid 
flow rate, consistent with the condition tolerance specified in Table 9 
of ISO 13256-1:1998 and adopt Table 11 of AHRI 340/360-2022, which 
specifies an operating tolerance of 2 percent for liquid flow rate. Id.
    DOE requested commented on its proposal to adopt the AHRI 340/360-
2022 approach for setting liquid flow rate for the full-load cooling 
test, namely by specifying inlet and outlet liquid temperature 
conditions rather than using a manufacturer-specified flow rate. Id. 
Additionally, DOE requested feedback on its proposals to use 
manufacturer-specified part-load liquid flow rates for part-load tests, 
that the part-load flow rate be no higher than the full-load flow rate, 
and to use the full-load liquid flow rate if no part-load liquid flow 
rate is specified. Id. In relation to heating tests, DOE requested 
comment on its proposal to use the liquid flow rate determined from the 
full-load cooling test for all heating tests. Id. Lastly, DOE requested 
comment on its proposal to specify an operating tolerance of 2 percent 
and a condition tolerance of 1 percent for liquid flow rate in all 
tests with a target liquid flow rate. Id. at 87 FR 53331-53332.
    In response to the August 2022 NOPR, ClimateMaster and WaterFurnace 
stated that they disagree with the proposal to adopt the AHRI 340/360 
approach for setting liquid flow rate because it moves the test 
standard along a prescriptive path that would discourage innovation for 
improvements in pressure drop and flow rate in heat exchanger design. 
(ClimateMaster, No. 22 at pp. 9-10; WaterFurnace, No. 20 at pp. 8-9) 
ClimateMaster recommended that DOE allow manufacturers to specify a 
given flow rate for full-load cooling tests. (ClimateMaster, No. 22 at 
p. 10) ClimateMaster also commented that DOE should also specify a 
maximum limit of 3.5 GPM/ton, which ClimateMaster stated aligns with 
DOE's statements in the August 2022 NOPR that 3 GPM/ton is a typical 
water flow rate for WSHPs that results in a temperature rise of 
approximately a 10 [deg]F. (Id. at pp. 9-10) ClimateMaster commented 
that while flowrate is typically used and specified when testing WSHP 
equipment, this is not the case for temperature rise. (Id. p. 10) MIAQ 
recommended that DOE continue to support ISO 13256-1. (MIAQ, No. 23 at 
p. 7)
    Regarding the part-load liquid flow rates, ClimateMaster supported 
DOE's

[[Page 84215]]

proposal to use manufacturer-specified part-load liquid flow rates for 
part-load tests. (ClimateMaster, No. 22 at p. 10) ClimateMaster 
recommended that the full-load liquid flow rate should be used for 
part-load tests if the system does not automatically reduce the liquid 
flow rate in part-load operation to the part-load flow rate when 
installed. (Id.) WaterFurnace agreed with DOE's proposal to use 
manufacturer-specified part-load liquid flow rates for part-load tests 
and commented that supporting ISO 13256/AHRI 600 would solve the issue. 
(WaterFurnace, No. 20 at p. 9)
    Regarding liquid flow rate for heating tests, ClimateMaster 
supported DOE's proposal to use the full-load cooling liquid flow rate 
for all full-load heating tests. (ClimateMaster, No. 22 at p. 10) MIAQ 
commented that using the liquid flow rate determined from the full-load 
cooling test for all heating tests could be a problem in conditions 
where the saturated suction temperature is too high, overloading the 
compressor. (MIAQ, No. 23 at p. 7) MIAQ stated that this may not be an 
issue with a low enough EWT. (Id.) MIAQ commented that systems with 
inverter-driven compressors and active head pressure control may 
present challenges to fulfilling these tests. (Id.) WaterFurnace 
commented that supporting ISO 13256 and AHRI 600 would solve the issue. 
(WaterFurnace, No. 20 at p. 9) WaterFurnace commented that most 
standards have abandoned the prescriptive approach of determining 
liquid flow rate from the full-load cooling test to allow innovation 
and efficiency improvement. (Id.) WaterFurnace stated that using 
manufacturer-specified flow rate is preferred. (Id.)
    Regarding tolerances liquid flow rates, ClimateMaster, 
WaterFurnace, and MIAQ commented in support of DOE's proposal to 
specify an operating tolerance of 2 percent and a condition tolerance 
of 1 percent for liquid flow rate in all tests with a target liquid 
flow rate. (ClimateMaster, No. 22 at p. 10; WaterFurnace, No. 20 at p. 
9; MIAQ, No. 23 at p. 7)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. Section 
5.4.15 of AHRI 600-2023 includes provisions regarding liquid flow rate. 
Specifically, this section specifies use of a manufacturer-specified 
flow rate rather than a fixed temperature rise (as recommended by 
commenters), but, similar to ClimateMaster's recommendation, section 
5.4.15 also provides a maximum flow rate of 0.275 GPM per kBtu/h (which 
is equivalent to 3.3 GPM/ton, slightly lower than the 3.5 GPM/ton limit 
recommended in ClimateMaster's comment). Section 5.4.14 also specifies 
that a single manufacturer-specified flow rate be used for all tests, 
unless the equipment automatic adjusts flow rate or the liquid flow 
rate is reduced for operation at low EWTs for head pressure control, 
per section 5.9 of AHRI 600-2023. Further, section 5.4.15 specifies 
that if there is not a specified liquid flow rate and that the system 
does not provide automatic adjustment of the liquid flow that a liquid 
flow rate of 0.25 GPM per kBtu/h is used for all tests. It also 
specifies a liquid flow rate condition tolerance of 1 percent.
    DOE has concluded that the approach for liquid flow rate specified 
in AHRI 600-2023 provides a representative and appropriate approach for 
testing WSHPs. The use of manufacturer-specified flow rate provides 
flexibility to manufacturers while the maximum liquid flow rate limit 
prevents manufacturer specification of unrepresentatively high flow 
rates for testing. With regards to MIAQ's concern that using the liquid 
flow rate determined from the full-load cooling test for all heating 
tests could be a problem in conditions where the saturated suction 
temperature is too high, overloading the compressor, DOE notes that the 
provisions specified in AHRI 600-2023 and incorporated by reference in 
this final rule allow manufacturers to specify different flow rates for 
tests other than the full-load cooling test so long as the specified 
flow rates for other tests are (a) below the maximum flow rate of 0.275 
GPM per kBtu/h; and (b) achieved via automatic adjustment of the liquid 
flow rate by the equipment under test. Therefore, a manufacturer would 
have the ability to set different liquid flow rates for tests other 
than full-load cooling tests to ensure operation representative of how 
the equipment would operate under such conditions in field 
installations.
    DOE also considers the inclusions of these provisions in AHRI 600-
2023 to represent industry consensus on the most appropriate method for 
testing WSHPs. Therefore, for the reasons discussed, DOE is 
incorporating by reference into appendix C1 the liquid flow rate 
provisions from AHRI 600-2023 in this final rule.
6. Refrigerant Line Losses
    Split-system WSHPs have refrigerant lines that can transfer heat to 
and from their surroundings, which can incrementally affect measured 
capacity. To account for this transfer of heat (referred to as ``line 
losses''), the current DOE WSHP test procedure, through adoption of ISO 
13256-1:1998, provides that if line loss corrections are to be made, 
they shall be included in the capacity calculations (in section B4.2 
for the indoor air enthalpy method and in section C3.3 for the liquid 
enthalpy test method of ISO 13256-1:1998). 10 CFR 431.96. ISO 13256-
1:1998 does not specify the circumstances that require line loss 
corrections nor the method to use to determine an appropriate 
correction.
    Section 7.3.3.4 of ANSI/ASHRAE 37-2009, the method of test 
referenced in AHRI 340/360-2022, specifies more detailed provisions to 
account for line losses of split systems in the outdoor air enthalpy 
method, and section 7.6.7.1 of ANSI/ASHRAE 37-2009 specifies to use the 
same provisions for the outdoor liquid coil method.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
specific sections of AHRI 340/360-2022. 87 FR 53302, 53332. AHRI 340/
360-2022 in turn references sections 7.6.7.1 and 7.3.3.4 of ANSI/ASHRAE 
37-2009. Id. Sections 7.6.7.1 and 7.3.3.4 of ANSI/ASHRAE 37-2009 
specify calculations for determining the line losses for bare copper or 
insulated lines. Id. DOE requested comment on the proposal to adopt the 
provisions for line loss adjustments included in sections 7.6.7.1 and 
7.3.3.4 of ANSI/ASHRAE 37-2009 through incorporation by reference of 
AHRI 340/360-2022. Id.
    In response to the August 2022 NOPR, ClimateMaster commented that 
adopting the line loss adjustments in ASHRAE 37-2009 is acceptable, as 
it is an industry best practice, but ClimateMaster stated it does not 
produce any split system heat pumps for use in commercial applications. 
(ClimateMaster, No. 22 at p.10) ClimateMaster recommended that DOE work 
with industry to create a national deviation of ISO 13256-1:1998 that 
adopts the provisions of ANSI/ASHRAE 37-2009. (Id.) WaterFurnace agreed 
with DOE's proposal. (WaterFurnace, No. 20 at p. 9)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 5.1 of AHRI 600-2023. This section in turn references 
sections 7.6.7.1 and 7.3.3.4 of ANSI/ASHRAE 37-2009, which is 
consistent with the proposal from the August 2022 NOPR. DOE considers 
the inclusion of these provisions in the AHRI 600-2023 to represent 
industry consensus that these provisions provide an appropriate method 
for testing WSHPs. As a result, DOE is incorporating by reference into 
appendix C1 the methods from AHRI

[[Page 84216]]

600-2023 for calculating line loss adjustments in this final rule.
7. Airflow Measurement
    The current DOE WSHP test procedure, through adoption of section 
D.1 of ISO 13256-1:1998, requires airflow measurements to be made in 
accordance with the provisions specified in several different industry 
test standards, ``as appropriate.'' \14\ 10 CFR 431.96. However, ISO 
13256-1:1998 is not explicit regarding the circumstances under which 
the different airflow measurement approaches included in these industry 
test standards should be used.
---------------------------------------------------------------------------

    \14\ The cited industry test standards include: ISO 3966:1977, 
``Measurement of fluid flow in closed conduits--Velocity area method 
using Pitot static tubes;'' ISO 5167-1:1991, ``Measurement of fluid 
flow by means of pressure differential devices--Part 1: Orifice 
plates, nozzles and Venturi tubes inserted in circular cross-section 
conduits running full;'' and ISO 5221:1984, ``Air Distribution and 
air diffusion--Rules to methods of measuring airflow rate in an air 
handling duct.'' These standards can be purchased from the ISO store 
at https://www.iso.org/store.html.
---------------------------------------------------------------------------

    Section F8 of ISO 13256-1:1998 specifies the requirements for the 
nozzle apparatus used to measure airflow. This device determines 
airflow by measuring the change in pressure across a nozzle of known 
geometry. Airflow derivations using this approach often include a 
discharge coefficient (i.e., the ratio of actual discharge air to 
theoretical discharge air) to account for factors that reduce the 
actual discharge air, such as nozzle resistance and airflow turbulence. 
In general, as the nozzle throat diameter decreases, nozzle resistance 
increases, thereby reducing actual discharge which is characterized by 
a lower discharge coefficient. Turbulent airflow (as characterized by 
Reynolds numbers \15\) and temperature also impact the discharge 
coefficient.
---------------------------------------------------------------------------

    \15\ ``Reynolds number'' is a dimensionless number that 
characterizes the flow properties of a fluid. Section F8.9 of ISO 
13256-1:1998 includes an equation for calculating Reynolds number 
that depends on a temperature factor, air velocity, and throat 
diameter.
---------------------------------------------------------------------------

    Section F8.9 of ISO 13256-1:1998 specifies that it is preferable to 
calibrate the nozzles in the nozzle apparatus, but that nozzles of a 
specific geometry may be used without calibration and by using the 
appropriate discharge coefficient specified in a lookup table in 
section F8.9 of ISO 13256-1:1998. ISO 13256-1:1998 does not specify the 
method that should be applied, however, to determine the coefficient of 
discharge for conditions that do not exactly match the values provided 
in the look-up table.
    Elsewhere, sections 6.2 and 6.3 of ANSI/ASHRAE 37-2009 includes 
provisions regarding the nozzle airflow measuring apparatus that are 
identical to the provisions in section F8 of ISO 13256-1:1998, except 
for the method used to determine the coefficient of discharge. Section 
6.3.3 of ANSI/ASHRAE 37-2009 uses a calculation in place of the look-up 
table used in ISO 13256-1:1998, thereby allowing determination of the 
coefficient of discharge at any point within the specified range.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
specific sections of AHRI 340/360-2022. 87 FR 53302, 53333. AHRI 340/
360-2022 in turn references the test method in ANSI/ASHRAE 37-2009. Id. 
Sections 6.2 and 6.3 of ANSI/ASHRAE 37-2009 include provisions 
regarding the nozzle airflow measuring apparatus that are identical to 
the provisions in section F8 of ISO 13256-1:1998, except for the method 
used to determine the coefficient of discharge. Id. Section 6.3.3 of 
ANSI/ASHRAE 37-2009 uses a calculation to determine the coefficient of 
discharge, thereby allowing determination of the coefficient of 
discharge at any point within the specified range. Id. DOE requested 
comment on the proposal to adopt the calculation of discharge 
coefficients and air measurement apparatus requirements as specified in 
ANSI/ASHRAE 37-2009. Id.
    In response to the August 2022 NOPR, ClimateMaster supported DOE's 
proposal to adopt the calculation of discharge coefficients and air 
measurement apparatus requirements of ANSI/ASHRAE 37-2009, as it is an 
industry best practice, and recommended that DOE work with industry to 
create a national deviation of ISO 13256-1:1998 that includes the 
provisions of ANSI/ASHRAE 37-2009. (ClimateMaster No. 22 at p. 10) 
WaterFurnace agreed with DOE's proposal. (WaterFurnace, No. 20 at p. 9)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 5.1 of AHRI 600-2023. This section in turn references 
the test method in ANSI/ASHRAE 37-2009, which is consistent with the 
proposal from the August 2022 NOPR. DOE considers the inclusion of 
these provisions in AHRI 600-2023 to represent industry consensus that 
these provisions provide an appropriate method for testing WSHPs. As a 
result, DOE is incorporating by reference into appendix C1 the methods 
from AHRI 600-2023 for measuring airflow in this final rule.
8. Air Condition Measurement
    Indoor air temperature and humidity are key parameters that affect 
WSHP performance, and for this reason, ISO 13256-1:1998 requires 
accurate indoor air condition measurements. However, informative 
annexes E and F of ISO 13256-1:1998 specify few requirements for the 
methods used to measure indoor air temperature and humidity.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
appendix C of AHRI 340/360-2022. 87 FR 53302, 53333. Appendix C of AHRI 
340/360-2022 provides detailed specifications for the measurement of 
air conditions (including indoor air), including aspirating 
psychrometer requirements in section C3.2.1 of AHRI 340/360-2022 and 
sampling requirements in section C3.3 of AHRI 340/360-2022. Id. DOE 
requested commented on the proposal to adopt the air condition 
measurement provisions in appendix C of AHRI 340/360-2022. Id.
    In response to the August 2022 NOPR, ClimateMaster supported DOE's 
proposal to adopt the air condition measurement provisions in appendix 
C of AHRI 340/360-2022, as it is industry best practice, and 
recommended that DOE work with industry to create a national deviation 
of ISO 13256-1:1998 that includes similar air condition measurement 
provisions. (ClimateMaster No. 22 at p. 11) WaterFurnace agreed with 
DOE's proposal. (WaterFurnace No. 20 at p. 9)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes appendix C of AHRI 600-2023. This language is consistent with 
appendix C of AHRI 340/360-2022, as proposed in the August 2022 NOPR, 
and addresses comments that DOE should adopt AHRI 600. DOE considers 
the air condition measurement approach specified in AHRI 600-2023 to 
represent industry consensus regarding the most appropriate method for 
measuring air conditions for WSHPs. As a result, DOE is incorporating 
by reference into appendix C1 the methods from AHRI 600-2023 for 
measuring air conditions in this final rule.
9. Duct Losses
    In the calculations for cooling and heating capacities for the 
indoor air enthalpy test method of ISO 13256-1:1998, the test standard 
includes a footnote in sections B3 and B4 of annex B stating that the 
equations do not provide allowances for heat leakage in the test 
equipment (i.e., duct losses). In

[[Page 84217]]

contrast, section 7.3.3.3 of ANSI/ASHRAE 37-2009 requires adjustments 
for such heat leakages and specifies methods to calculate appropriate 
values for the adjustments.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
specific sections of AHRI 340/360-2022. 87 FR 53302, 53334. AHRI 340/
360-2022 in turn references section 7.3.3.3 of ASHRAE 37-2009, which 
requires and provides equations for duct loss adjustments. Id. DOE 
requested comment on whether the duct loss adjustments as described in 
section 7.3.3.3 of ANSI/ASHRAE 37-2009 or any other duct loss 
adjustments are used to adjust capacity measured using the indoor air 
enthalpy method when testing WSHPs. Id.
    In response to the August 2022 NOPR, ClimateMaster supported DOE's 
proposal to adopt the duct loss provisions as it is an industry best 
practice for companies that produce split-system heat pumps for use in 
commercial applications. (ClimateMaster, No. 22 at p. 11) ClimateMaster 
recommended that DOE work with industry to create a national deviation 
of ISO 13256-1:1998 that includes these provisions of ANSI/ASHRAE 37-
2009. (Id.) WaterFurnace agreed with DOE's proposal. (WaterFurnace, No. 
20 at pp. 9)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 5.1 of AHRI 600-2023. This section in turn references 
ANSI/ASHRAE 37-2009, including section 7.3.3.3, which is consistent 
with the proposal from the August 2022 NOPR. DOE considers the 
inclusion of these provisions in AHRI 600-2023 to represent industry 
consensus that these provisions provide an appropriate method for 
testing WSHPs. Therefore, DOE is incorporating by reference into 
appendix C1 the equations for duct loss adjustments from section 5.1 of 
AHRI 600-2023 in this final rule. Regarding the comment from 
ClimateMaster, DOE notes that these provisions for calculating duct 
losses apply to testing all WSHPs, not just split systems.
10. Refrigerant Charging
    The amount of refrigerant can have a significant impact on the 
system performance of air conditioners and heat pumps. DOE's current 
test procedure for WSHPs requires that units be set up for test in 
accordance with the manufacturer installation and operation manuals. 10 
CFR 431.96(e). In addition, the current DOE test procedure states that 
if the manufacturer specifies a range of superheat, sub-cooling, and/or 
refrigerant pressures in the installation and operation manual, any 
value within that range may be used to determine refrigerant charge or 
mass of refrigerant, unless the manufacturer clearly specifies a rating 
value in its installation or operation manual, in which case the 
specified rating value shall be used. 10 CFR 431.96(e)(1) However, the 
current DOE test procedure for WSHPs does not provide charging 
instructions to be used if the manufacturer does not provide 
instructions in the manual that is shipped with the unit or if the 
provided instructions are unclear or incomplete. In addition, ISO 
13256-1:1998 does not provide any specific guidance on setting and 
verifying the refrigerant charge of a unit aside from stating in 
section A2.3 of that standard that equipment shall be evacuated and 
charged with the type and amount of refrigerant specified in the 
manufacturer's instructions, where necessary.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
section 5.8 of AHRI 340/360-2022. 87 FR 53302, 53334. This section 
specifies refrigerant charging parameters, including specifying which 
set of installation instructions to use for charging, explaining what 
to do if no instructions are provided, specifying that target values of 
parameters are the centers of the ranges allowed by installation 
instructions, and specifying tolerances for the measured values. Id. 
The approach also requires that refrigerant line pressure gauges be 
installed for single-package units, unless otherwise specified in 
manufacturer instructions. Id. DOE requested comment on the proposal to 
adopt the refrigerant charging requirements in section 5.8 of AHRI 340/
360-2022. Id. at 87 FR 53335.
    In response to the August 2022 NOPR, ClimateMaster commented that 
while all commercially single package WSHP units are developed with 
specific factory system charge weights, the only provision DOE proposed 
for a charge weight tolerance is in Table 4 of section 5.8.3 of AHRI 
340/360-2022, which specifies a tolerance of 2 oz. 
(ClimateMaster, No. 22 at p. 11) ClimateMaster commented that it 
considers this tolerance unacceptable, as 2 oz can be upwards of 10 
percent of the overall system charge on small capacity heat pumps. 
(Id.) ClimateMaster further stated that the procedures for charging 
that DOE provided in sections 5.8.4.1 and 5.8.4.2 of AHRI 340/360-2022 
are not applicable as most single package systems do not contain a 
liquid line service connection. (Id.) ClimateMaster commented that the 
tolerances that DOE provided in Table 4 of section 5.8.3 of AHRI 340/
360-2022 reference items related to outdoor air conditions, which are 
not applicable to WSHPs. (Id.) ClimateMaster commented that DOE's 
proposal lacks provisions for the possibility that the operating mode 
of the system could set the charge. (Id.) For these reasons, 
ClimateMaster recommended that DOE work with industry to create a 
national deviation of ISO 13256-1:1998 that allows the WSHP industry to 
develop a list of charging provisions that meet the intent of those 
found in AHRI 340/360-2022. (Id.) WaterFurnace agreed with DOE's 
proposal regarding refrigerant charging. (WaterFurnace, No. 20 at p. 9)
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 5.4.11 of AHRI 600-2023. This language is consistent 
with section 5.8 of AHRI 340/360-2022, as proposed for use in the 
August 2022 NOPR, and addresses commenters' concerns that DOE should 
adopt AHRI 600. With regards to the comment from ClimateMaster 
regarding the refrigerant charging proposals in the August 2022 NOPR 
(which are consistent with the provisions in AHRI 600-2023), DOE notes 
that these provisions are used only if the manufacturer's charging 
instructions do not specify a tighter charging tolerance (as specified 
in section 5.4.11.4 of AHRI 600-2023). Therefore, these provisions 
provide flexibility to manufacturers to specify charging instructions 
appropriate to their models and serve mainly to address cases in which 
manufacturer's instructions provide inadequate, incomplete, or 
conflicting charging instructions. Specifically, these provisions allow 
manufacturers to specify tighter tolerances and/or to specify charging 
based on whatever method is most appropriate for a given model.
    DOE considers the inclusion of these provisions in AHRI 600-2023 to 
represent industry consensus that these provisions provide an 
appropriate method for testing WSHPs. Therefore, DOE is incorporating 
by reference into appendix C1 the refrigerant charging requirements 
from section 5.4.11 of AHRI 600-2023 in this final rule.
11. Voltage
    Operating voltage can affect the measured efficiency of air 
conditioners and heat pumps. The current DOE WSHP test procedure, 
through adoption of Tables 1 and 2 of ISO 13256-1:1998, requires units 
rated with dual nameplate voltages to be tested at both

[[Page 84218]]

voltages or at the lower voltage if only a single rating is to be 
published. 10 CFR 431.96.
    In the August 2022 NOPR, DOE proposed to incorporate by reference 
section 6.1.3.1 of AHRI 340/360-2022. 87 FR 53302, 53335. Section 
6.1.3.1 of AHRI 340/360-2022 specifies that units with dual nameplate 
voltage ratings must be tested at the lower of the two voltages if only 
a single standard rating is to be published, or at both voltages if two 
standard ratings are to be published. Id. This approach is equivalent 
to the approach for dual nameplate voltages specified in tables 1 and 2 
of ISO 13256-1:1998 and tables 2 and 3 of ISO 13256-1:2021. Id. DOE 
requested commented on the proposal to adopt the voltage provisions in 
section 6.1.3.1 of AHRI 340/360-2022. Id.
    In response to the August 2022 NOPR, ClimateMaster supported DOE's 
proposal to adopt the voltage provisions in section 6.1.3.1 of AHRI 
340/360-2022 because it is industry best practice and recommended that 
DOE work with industry to create a national deviation of ISO 13256-
1:1998 that includes the proposed language. (ClimateMaster, No. 22 at 
pp. 11-12) WaterFurnace agreed with DOE's proposal. (WaterFurnace, No. 
20 at p. 9).
    As discussed in section III.D of this final rule, DOE is 
incorporating by reference AHRI 600-2023 into appendix C1. This 
includes section 6.2.2 of AHRI 600-2023. This language is consistent 
with section 6.1.3.1 of AHRI 340/360-2022, which was proposed in the 
August 2022 NOPR, as well as with tables 1 and 2 of ISO 13256-1:1998 
and tables 2 and 3 of ISO 13256-1:2021. DOE considers the inclusion of 
these voltage provisions in AHRI 600-2023 to represent industry 
consensus that these provisions provide an appropriate method for 
testing WSHPs. As a result, DOE is incorporating by reference into 
appendix C1 the voltage provisions from AHRI 600-2023 in this final 
rule.
12. Non-Standard Low-Static Indoor Fan Motors
    As discussed in section III.F.1.a of this document, DOE is adopting 
higher ESPs for WSHPs with a cooling capacity greater than or equal to 
75,000 Btu/h that are included in section 5.5.1.1 of AHRI 600-2023 and 
are consistent with the ESP levels recommended in the ACUAC and ACUHP 
Working Group TP Term Sheet. However, individual models of WSHPs in 
this capacity range with indoor fan motors intended for installation in 
applications with a low ESP may not be able to operate at the proposed 
full-load ESP requirements at the full-load indoor rated airflow. To 
address this situation, section 3.2.30 of AHRI 600-2023 defines ``non-
standard low-static indoor fan motors'' as motors in units with cooling 
capacity greater than or equal to 75,000 Btu/h which cannot maintain 
ESP as high as specified in the test procedure when operating at the 
full-load rated indoor airflow and that are distributed in commerce as 
part of an individual model within the same basic model that is 
distributed in commerce with a different motor specified for testing 
that can maintain the required ESP. Section 5.7.4.3 of AHRI 600-2023 
includes test provisions for WSHPs with non-standard low-static indoor 
fan motors that cannot reach the ESP within tolerance during testing, 
which require using the maximum available fan speed that does not 
overload the motor or motor drive, adjusting the airflow-measuring 
apparatus to maintain airflow within tolerance, and operating with an 
ESP as close as possible to the minimum ESP requirements for testing. 
This approach is consistent with the industry test standard referenced 
by the DOE test procedure for DX-DOASes (AHRI 920-2020, section 
6.5.2.5). See appendix B to 10 CFR 431.96.
    As discussed in section III.G.3 of this document, DOE is clarifying 
that representations for a WSHP basic model must be based on the least 
efficient individual model(s) distributed in commerce within the basic 
model (with the exception specified in 10 CFR 429.43(a)(3)(v)(A) for 
certain individual models with the components listed in Table 6 to 10 
CFR 429.43(a)(3)). DOE has concluded that the combination of (1) the 
provisions in AHRI 600-2023 for testing models with ``non-standard low-
static indoor fan motors'' with (2) the requirement that basic models 
be rated based on the least efficient individual model (with certain 
exceptions, as discussed) provides an appropriate approach for handling 
WSHP models with these motors because if an individual model with a 
non-standard low-static indoor fan motor is tested, the test would be 
conducted at an indoor airflow representative for that model. But 
because testing at the rated airflow for such an individual model would 
result in testing at an ESP lower than the requirement and thus a lower 
indoor fan power, the representations for that basic model will be 
required to be based on an individual model with an indoor fan motor 
that can achieve the ESP requirements at the rated airflow. Consistent 
with incorporating by reference AHRI 600-2023 into appendix C1, in this 
final rule, DOE is adopting the AHRI 600-2023 provisions for testing 
models with non-standard low-static indoor fan motors.

G. Configuration of Unit Under Test

1. Background and Summary
    WSHPs are sold with a wide variety of components, including many 
that can optionally be installed on or within the unit both in the 
factory and in the field. In all cases, these components are 
distributed in commerce with the WSHP but can be packaged or shipped in 
different ways from the point of manufacturer for ease of 
transportation. Each optional component may or may not affect a model's 
measured efficiency when tested to the DOE test procedure adopted in 
this final rule. For certain components not directly addressed in the 
DOE test procedure, DOE proposed to adopt more specific instructions on 
how each component should be handled for the purposes of making 
representations in 10 CFR part 429 in the August 2022 NOPR. 87 FR 
53302, 53335. Specifically, the proposed instructions provide 
manufacturers clarity on how components should be treated and how to 
group individual models with and without optional components for the 
purposes of representations to reduce burden. Id.
    As proposed in the August 2022 NOPR, DOE is handling WSHP 
components in two distinct ways in this final rule to help 
manufacturers better understand their options for developing 
representations for their differing product offerings. Id. First, as 
proposed in the August 2022 NOPR, the treatment of some components is 
specified by the test procedure to limit their impact on measured 
efficiency. Id. For example, a fresh air damper must be set in the 
closed position and sealed during testing, resulting in a measured 
efficiency that would be similar or identical to the measured 
efficiency for a unit without a fresh air damper. Id.
    Second, for certain components not directly addressed in the DOE 
test procedure, this final rule adopts the specific instructions 
proposed in the August 2022 NOPR on how each component should be 
handled for the purposes of making representations in 10 CFR part 429. 
See Id. at 87 FR 53335-53336. Specifically, these instructions provide 
manufacturers clarity on how components should be treated and how to 
group individual models with and without optional components for the 
purposes of representations, in order to reduce burden. DOE is adopting 
these provisions in 10 CFR part 429 to allow for testing of certain 
individual models

[[Page 84219]]

that can be used as a proxy to represent the performance of equipment 
with multiple combinations of components. DOE is adopting provisions 
expressly allowing certain models to be grouped together for the 
purposes of making representations and allowing the performance of a 
model without certain optional components to be used as a proxy for 
models with any combinations of the specified components, even if such 
components would impact the measured efficiency of a model. Steam/
hydronic heat coils are an example of such a component. The efficiency 
representation for a model with a steam/hydronic heat coil is based on 
the measured performance of the WSHP as tested without the component 
installed because the steam/hydronic heat coil is not easily removed 
from the WSHP for testing.\16\ Id.
---------------------------------------------------------------------------

    \16\ Note that in certain cases, as explained further in section 
III.G.3.c of this document, the representation may have to be based 
on an individual model with a steam/hydronic coil.
---------------------------------------------------------------------------

    In this final rule, DOE is adopting these provisions in 10 CFR part 
429 as proposed to allow for testing of certain individual models that 
can be used as a proxy to represent the performance of equipment with 
multiple combinations of components, though DOE is also adopting 
provisions that address additional components not included in the 
August 2022 NOPR, reflecting comments received in response to the 
August 2022 NOPR and provisions in AHRI 600-2023.
2. Components Addressed Through Test Provisions of 10 CFR Part 431, 
Subpart F, Appendix C1
    In the August 2022 NOPR, DOE proposed test provisions for specific 
components, including all of the components listed in section D3 of 
AHRI 340/360-2022 for which there is a test procedure action which 
limits the impacts on measured efficiency (i.e., test procedure 
provisions specific to the component that are not addressed by general 
provisions in AHRI 340/360-2022 that negates the component's impact on 
performance). Id. at 87 FR 53336. These provisions specified how to 
test a unit with such a component (e.g., for a unit with hail guards, 
remove hail guards for testing). Id. The proposed test provisions were 
consistent with the provision in section D3 of AHRI 340/360-2022 but 
included revisions for further clarity and specificity (e.g., adding 
clarifying provisions for how to test units with modular economizers as 
opposed to units shipped with economizers installed). Id. Specifically, 
DOE proposed to require in appendix C1 that steps be taken during unit 
set-up and testing to limit the impacts on the measurement of these 
components:

 Desiccant Dehumidification Components
 Air Economizers
 Fresh Air Dampers
 Power Correction Capacitors
 Ventilation Energy Recovery Systems (VERS)
 Barometric Relief Dampers
 UV Lights
 Steam/Hydronic Coils
 Refrigerant Reheat
 Fire/Smoke/Isolation Dampers
 Process Heat Recovery/Reclaim Coils/Thermal Storage.
Id. at 87 FR 53336-53337.

    As DOE did not receive any comments regarding this proposal in 
response to the August 2022 NOPR, it is adopting the provisions as 
proposed in this final rule.
3. Components Addressed Through Representation Provisions of 10 CFR 
429.43
    In the August 2022 NOPR, consistent with the Commercial HVAC Term 
Sheet and the Commercial HVAC Enforcement Policy, DOE proposed 
provisions that explicitly allow representations for individual models 
with certain components to be based on testing for individual models 
without those components and proposed a table (``Table 6 to Paragraph 
(a)(3)(v)(A)'') \17\ at 10 CFR 429.43(a)(3) listing the components for 
which these provisions would apply. Id. at 87 FR 53337. There are three 
components specified explicitly for WSHPs in the Commercial HVAC 
Enforcement Policy that are not included in section D3 of AHRI 340/360-
2022: (1) Condenser Pumps/Valves/Fittings; (2) Condenser Water Reheat; 
and (3) Electric Resistance Heaters. Id. DOE tentatively concluded that 
the inclusion of these components as optional components for WSHPs is 
appropriate, except for electric resistance heaters. Id. DOE 
tentatively determined that electric resistance heaters would have a 
negligible effect on tested efficiency as they would be turned off for 
test and not impose a significant pressure drop. Id. DOE proposed the 
following components be listed in Table 6 to Paragraph (a)(3)(v)(A):
---------------------------------------------------------------------------

    \17\ DOE notes that in the August 2022 NOPR, DOE referred to 
this table as ``Table 1 to Paragraph (a)(3)(ii)(A) .'' Due to the 
publication of other regulatory documents, DOE is now referring to 
this Table as ``Table 6 to Paragraph (a)(3)(v)(A).''

 Desiccant Dehumidification Components,
 Air Economizers,
 Ventilation Energy Recovery Systems (VERS),
 Steam/Hydronic Heat Coils,
 Refrigerant Reheat, Fire/Smoke/Isolation Dampers,
 Powered Exhaust/Powered Return Air Fans,
 Sound Traps/Sound Attenuators,
 Process Heat Recovery/Reclaim Coils/Thermal Storage,
 Indirect/Direct Evaporative Cooling of Ventilation Air,
 Condenser Pumps/Valves/Fittings,
 Condenser Water Reheat,
 Grill Options,
 Non-Standard Indoor Fan Motors.
Id.

    Additionally, DOE proposed to specify that the basic model 
representation must be based on the least efficient individual model 
that is a part of the basic model and clarified how this long-standing 
basic model provision interacts with the component treatment in 10 CFR 
429.43 that was proposed. Id. DOE proposed clarifying instructions for 
instances when individual models within a basic model may have more 
than one of the specified components and there may be no individual 
model without any of the specified components. Id. DOE proposed the 
concept of an ``otherwise comparable model group'' (``OCMG''). Id.
    As discussed in the August 2022 NOPR, an OCMG is a group of 
individual models within the basic model that do not differ in 
components that affect energy consumption as measured according to the 
applicable test procedure other than the specific components listed in 
Table 6 to Paragraph (a)(3)(v)(A) but may include individual models 
with any combination of such specified components. Id. Therefore, a 
basic model can be composed of multiple OCMGs, each representing a 
unique combination of components that affect energy consumption as 
measured according to the applicable test procedure, other than the 
specified excluded components listed in Table 6 to Paragraph 
(a)(3)(v)(A). Id. For example, a manufacturer might include two tiers 
of control system within the same basic model, in which one of the 
control systems has sophisticated diagnostics capabilities that require 
a more powerful control board with a higher wattage input. Id. WSHP 
individual models with the ``standard'' control system would be part of 
OCMG A, while individual models with the ``premium'' control system 
would be part of a different OCMG B, because the

[[Page 84220]]

control system is not one of the specified exempt components listed in 
Table 6 to Paragraph (a)(3)(v)(A). Id. However, both OCMGs may include 
different combinations of specified exempt components. Id. Also, both 
OCMGs may include any combination of characteristics that do not affect 
the efficiency measurement, such as paint color. Id.
    Further discussed in the August 2022 NOPR, an OCMG is used to 
determine which individual models are used to determine a represented 
value. Id. Specifically, when identifying the individual model within 
an OCMG for the purpose of determining a representation for the basic 
model, only the individual model(s) with the least number (which could 
be zero) of the specific components listed in Table 6 to Paragraph 
(a)(3)(v)(A) is considered. Id. This clarifies which individual models 
are exempted from consideration for determination of represented values 
in the case of an OCMG with multiple specified components and no 
individual models with zero specific components listed in Table 6 to 
(a)(3)(v)(A) (i.e., models with a number of specific components listed 
in Table 6 to (a)(3)(v)(A) greater than the least number in the OCMG 
are exempted). Id. In the case that the OCMG includes an individual 
model with no specific components listed in Table 6 to Paragraph 
(a)(3)(v)(A), then all individual models in the OCMG with specified 
components would be exempted from consideration. Id. The least-
efficient individual model across the OCMGs within a basic model would 
be used to determine the representation of the basic model. Id. In the 
case where there are multiple individual models within a single OCMG 
with the same non-zero least number of specified components, the least 
efficient of these would be considered. Id.
    In the August 2022 NOPR, DOE relied on the term ``comparable'' as 
opposed to ``identical'' to indicate that for the purpose of 
representations, the components that impact energy consumption as 
measured by the applicable test procedure are the relevant components 
to consider. Id. In other words, differences that do not impact energy 
consumption, such as unit color and presence of utility outlets, would 
not warrant separate OCMGs. Id.
    The use of the OCMG concept results in the represented values of 
performance that are representative of the individual model(s) with the 
lowest efficiency found within the basic model, excluding certain 
individual models with the specific components listed in Table 6 to 
Paragraph (a)(3)(v)(A). Id. at 87 FR 53337-53338. Further, the 
approach, as proposed, was structured to more explicitly address 
individual models with more than one of the specific components listed 
in Table 6 to Paragraph (a)(3)(v)(A), as well as instances in which 
there is no comparable model without any of the specified components. 
Id. at 87 FR 53338. DOE developed a document of examples to illustrate 
the approach proposed in the August 2022 NOPR for determining 
represented values for WSHPs with specific components, and in 
particular the OCMG concept. See EERE-2017-BT-TP-0029; 87 FR 53302, 
53338.
    In the August 2022 NOPR, DOE proposed provisions in 10 CFR 
429.43(a)(3)(v)(A) that included each of the components specified in 
section D3 of AHRI 340/360-2022 for which the test provisions for 
testing a unit with these components may result in differences in 
ratings compared to testing a unit without these components, except for 
the following features: (1) Evaporative Pre-cooling of Condenser Intake 
Air; (2) Non-Standard Ducted Condenser Fans; and (3) Coated Coils. 87 
FR 53302, 53338-53339.
    In response to the August 2022 NOPR, ClimateMaster commented that 
it agrees with DOE's several proposals on this issue, but it believes 
that Table 6 in paragraph (a)(3) should include additional components, 
specifically water-side economizers and high effectiveness filters. 
(ClimateMaster, No. 22 at p. 12) ClimateMaster recommended that DOE 
create a national deviation of ISO 13256-1:1998 that adopts the 
proposed language with modifications to include water-side economizers 
and high effectiveness indoor filters. (Id.) WaterFurnace commented 
that the proposals may work for large motors but noted that the small 
volume of these larger motors would not justify regulation efforts and 
AHRI 340/360 omits smaller motors. (WaterFurnace, No. 20 at p. 10)
    With regards to the comment from ClimateMaster that waterside 
economizers and high effectiveness filters should be included in Table 
6 to Paragraph (a)(3)(v)(A), DOE notes that the impact of high 
effectiveness filters can be entirely mitigated by testing with a 
standard filter, which is required by section 5.4.5 of AHRI 600-2023. 
Therefore, DOE has concluded that treatment as specific components in 
representation provisions in 10 CFR 429.43 is not warranted for high 
effectiveness filters. With regards to waterside economizers, DOE has 
included waterside economizers and desuperheaters in the updated Table 
6 to Paragraph (a)(3)(v)(A) adopted in this final rule, as DOE has 
determined that it is appropriate to make representations for WSHPs 
without these components present, consistent with the inclusion of 
these components in section D3 of AHRI 600-2023.
    With regard to the comment from WaterFurnace that only a small 
portion of the market has larger motors and therefore that they are not 
worth regulating, DOE notes that the approach for non-standard high-
static indoor fan motors (as proposed in the August 2022 NOPR and 
included in AHRI 600-2023) does not expand the scope of regulations to 
cover equipment with higher-static motors. Equipment that meets the DOE 
definition of WSHP is covered equipment, regardless of the size of 
indoor fan motor. The adopted approach reduces burden to manufacturers 
by allowing grouping of WSHP individual models with non-standard high-
static indoor fan motors in the same basic model as corresponding 
individual models with standard indoor fan motors (and thus rating all 
individual models in the basic model based on performance with the 
standard indoor fan motor), as long as the non-standard high-static 
indoor fan motor has the same or better relative efficiency performance 
as the standard motor included in the individual model with the 
standard indoor fan motor.
4. Enforcement Provisions of 10 CFR 429.134
    In the August 2022 NOPR, consistent with the Commercial HVAC Term 
Sheet and the Commercial HVAC Enforcement Policy, DOE proposed 
provisions in 10 CFR 429.134(dd)(2) \18\ regarding how DOE would assess 
compliance for basic models that include individual models distributed 
in commerce if DOE cannot obtain for testing individual models without 
the components that are the basis of representation. 87 FR 53302, 
53339. Specifically, DOE proposed that if a basic model includes 
individual models with components listed at Table 6 to Paragraph 
(a)(3)(v)(A) and DOE is not able to obtain an individual model with the 
least number of those components within an OCMG (as defined in 10 CFR 
429.43(a)(3) and discussed in section III.G.3.b of this final rule), 
DOE may test any individual model within the OCMG. Id.
---------------------------------------------------------------------------

    \18\ DOE notes that in the August 2022 NOPR, DOE referred to 
this section as ``10 CFR 429.134(t)(2).'' Due to the publication of 
other regulatory documents, DOE is now referring to this section as 
``10 CFR 429.134(dd)(2).''
---------------------------------------------------------------------------

    In response to the August 2022 NOPR, ClimateMaster stated that it 
disagrees

[[Page 84221]]

with the provisions proposed in 10 CFR 429.134(dd)(2) in the August 
2022 NOPR, stating that most WSHPs are built for specific orders based 
on given configurations or options. (ClimateMaster, No. 22 at p. 12) 
ClimateMaster commented that if DOE requires an individual model with 
the lowest number of specific components, it may not be available to 
test, and that the proposal would allow DOE testing with a model that 
includes the specific component. (Id.) ClimateMaster recommended that 
DOE instead allow a manufacturer to provide an individual model with 
the least number of specific components within a specific and agreed-
upon timeframe (i.e., rather than testing a model that includes a 
specific component). (Id.)
    With regards to the comment from ClimateMaster, the provisions 
proposed in the August 2022 NOPR at 10 CFR 429.134(dd)(2) specify that 
DOE may test any individual model within the otherwise comparable model 
group if DOE is not able to obtain an individual model with the least 
number (which could be zero) of those components within the otherwise 
comparable model group. DOE will attempt to obtain a model with the 
least number of those components of specific components listed at Table 
6 to Paragraph (a)(3)(v)(A). However, if DOE is unable to obtain such a 
model, DOE must retain the option to conduct assessment testing on an 
available model, and thus, in this final rule, DOE is adopting the 
provisions from the NOPR as proposed, at 10 CFR 429.134(dd)(2).

H. Represented Values and Enforcement

1. Cooling Capacity
    For WSHPs, cooling capacity determines equipment class, which in 
turn determines the applicable energy conservation standard. 10 CFR 
431.97. In the August 2022 NOPR, DOE noted that while cooling capacity 
is a required represented value for WSHPs, DOE does not currently 
specify provisions for WSHPs regarding how close the represented value 
of cooling capacity must be to the tested or AEDM-simulated cooling 
capacity, or whether DOE will use measured or certified cooling 
capacity to determine equipment class for enforcement testing. 87 FR 
53302, 53339. DOE proposed to add the following provisions regarding 
cooling capacity for WSHPs: (1) a requirement that the represented 
cooling capacity be between 95 percent and 100 percent of the tested or 
AEDM-simulated cooling capacity; and (2) an enforcement provision 
stating that DOE would use the mean of measured cooling capacity values 
from testing, rather than the certified cooling capacity, to determine 
the applicable standards. Id.
    In response to the August 2022 NOPR, ClimateMaster commented that 
it supports DOE's proposal for the published capacity to fall within 95 
percent to 100 percent of the tested value or the value found through 
the AEDM. (ClimateMaster, No. 22 at p. 12) WaterFurnace commented that 
it saw no problem with DOE's proposal. (WaterFurnace, No. 20 at p. 10) 
MIAQ commented that it supports the tolerance of 5 percent below the 
rated/marked capacity, but not with the 100-percent limit. (MIAQ, No. 
23 at p. 8) MIAQ stated that manufacturers must account for many 
tolerances in their system, causing them to rate their units 
conservatively, and this conservative rating will not impact customers 
because the unit will perform better than advertised. (Id.)
    In response to the comment from MIAQ, DOE notes that the proposed 
cooling capacity provisions specify that the represented cooling 
capacity be between 95 percent and 100 percent of the tested or AEDM-
simulated cooling capacity, which allows for conservative rating up to 
5 percent--i.e., the represented cooling capacity may be 5 percent 
lower than the tested or AEDM-simulated cooling capacity. MIAQ's 
comment suggests MIAQ interpreted the proposal to mean the tested or 
simulated capacity cannot exceed 100 percent of represented capacity, 
which would not allow conservative ratings. However, DOE has concluded 
that MIAQ's concern that conservative rating should be allowed is 
addressed in the proposed provisions because the cooling capacity 
provisions explicitly allow conservative ratings up to 5 percent. 
Therefore, for the reasons discussed in the August 2022 NOPR and 
previously in this section, DOE is adopting the cooling capacity 
representation and enforcement provisions as proposed at 10 CFR 
429.43(a)(3)(v)(B) and 10 CFR 429.134(dd)(1), respectively.
2. Enforcement of IEER
    In the August 2022 NOPR, DOE proposed two options for determination 
of IEER--``option 1'' based on testing at the EWTs specified in AHRI 
340/360-2022 for determining IEER, and ``option 2'' based on testing at 
the EWTs specified in ISO 13256-1:1998 and interpolating/extrapolating 
performance to the EWTs specified in AHRI 340/360-2022. 87 FR 53302, 
53339. For assessment or enforcement testing, DOE proposed provisions 
in 10 CFR 429.134(t)(3) specifying that that the Department would 
determine IEER according to the ``Option 1'' approach, unless the 
manufacturer has specified that the ``Option 2'' approach should be 
used for the purposes of enforcement, in which case the Department 
would determine IEER according to the ``Option 2'' approach. Id.
    As discussed in section III.E.1 of this final rule, DOE is not 
adopting two methods for determining IEER, and is instead adopting a 
single method for determining IEER by incorporating by reference AHRI 
600-2023 into appendix C1. Because this final rule includes only one 
method for determining IEER, the proposed enforcement provisions for 
the method of determination of IEER are no longer applicable, and DOE 
is not adopting the proposed provisions.

I. Test Procedure Costs

    EPCA requires that the test procedures for commercial package air 
conditioning and heating equipment, including WSHPs, be those generally 
accepted industry testing procedures or rating procedures developed or 
recognized by either AHRI or ASHRAE, as referenced in ASHRAE 90.1. (42 
U.S.C. 6314(a)(4)(A)) Further, if such an industry test procedure is 
amended, DOE must amend its test procedure to be consistent with the 
amended industry test procedure unless DOE determines, by rule 
published in the Federal Register and supported by clear and convincing 
evidence, that such an amended test procedure would not meet the 
requirements in 42 U.S.C. 6314(a)(2)-(3) related to representative use 
and test burden. (42 U.S.C. 6314(a)(4)(B)) EPCA also requires that, at 
least once every 7 years, DOE evaluate test procedures for each type of 
covered equipment, including WSHPs, to determine whether amended test 
procedures would more accurately or fully comply with the requirements 
for the test procedures to not be unduly burdensome to conduct and be 
reasonably designed to produce test results that reflect energy 
efficiency, energy use, and estimated operating costs during a 
representative average use cycle. (42 U.S.C. 6314(a)(1)
    In the August 2022 NOPR, DOE proposed to reorganize the current 
test procedure in proposed appendix C and to adopt generally through 
incorporation by reference the industry standard AHRI 340/360-2022 in 
proposed appendix C1. 87 FR 53302, 53340. The proposed amended test 
procedure in the proposed appendix C1 would rely on the IEER metric. 
Id. DOE tentatively determined that the proposed amended test procedure 
for WSHPs in appendix C1 would be

[[Page 84222]]

representative of an average use cycle and would not be unduly 
burdensome for manufacturers to conduct. Id. DOE also proposed to 
increase the scope of applicability of the test procedure to include 
all WSHPs with full-load cooling capacity between 135,000 Btu/h and 
760,000 Btu/h. Id. As part of the August 2022 NOPR, DOE presented 
estimates of the test costs associated with these proposals. Id. DOE 
requested comment on its understanding of the impact of the test 
procedure proposals in this NOPR. Id.
    In response to the August 2022 NOPR, ClimateMaster commented that 
it qualifies as a small business under the Small Business 
Administration (``SBA'') guidelines and that the extra burden to rate 
through two programs, as would be required under AHRI 340/360-2022, is 
too costly for small businesses. (ClimateMaster, No. 22 at pp. 13-14) 
ClimateMaster recommended that DOE should instead use data created 
through the national deviation to ISO 13256-1:1998 to interpolate per 
the procedure given in AHRI 600. (Id. at p. 14)
    WaterFurnace commented that that the test procedure proposed in the 
August 2022 NOPR referencing AHRI 340/360 (including changes to ESP 
requirements, flows, and entering air conditions) would approximately 
double its testing and certification management labor and costs. 
(WaterFurnace, No. 20 at p.10)
    In this final rule DOE is relocating the current DOE test procedure 
for WSHPs to appendix C without change. The test procedure adopted in 
appendix C for measuring EER and COP will result in no change in 
testing practices or burden.
    As discussed in section III.D of this final rule, DOE is 
incorporating by referencing AHRI 600-2023 into appendix C1 for 
measuring the IEER and ACOP metrics. DOE has determined that the 
amended test procedure is reasonably designed to produce results that 
are representative of the energy efficiency of that covered equipment 
during an average use cycle and is not unduly burdensome to conduct. 
The use of appendix C1 will not be required until the compliance date 
of any amended standards denominated in terms of IEER and ACOP, should 
DOE adopt such standards. DOE has concluded that the incorporation by 
reference AHRI 600-2023, the latest industry consensus test procedure 
for WSHPs, renders moot any expressed concerns related to the costs 
with rating to AHRI 340/360.
    In this final rule, DOE estimates that the cost for units less than 
135,000 Btu/h for third-party laboratory testing according to appendix 
C1 for measuring IEER and ACOP to be $3,700 for single speed units, 
$5,950 for two stage units, and $8,200 for variable speed units. The 
difference in test cost is attributable to the varying number of tests 
(i.e. 3, 6, or 9) required to determine IEER for units with different 
compressor types. Additionally, DOE is increasing the scope of 
applicability of the test procedure to include all WSHPs with full-load 
cooling capacity between 135,000 Btu/h and 760,000 Btu/h. DOE estimates 
the cost for third-party lab testing of large and very large WSHPs 
according to the test procedure adopted in appendix C1 for measuring 
IEER and ACOP to be $10,100 for single speed units, $15,500 for two 
stage units, and $20,900 for variable speed units. DOE estimates a 
substantially higher cost for larger WSHPs because they are generally 
more difficult to set up due to size and larger units typically would 
need to be set up in larger test chambers with more limited 
availability.
    As discussed in the August 2022 NOPR, in accordance with 10 CFR 
429.70, WSHP manufacturers may elect to use AEDMs. 87 FR 53302, 53340. 
An AEDM is a computer modeling or mathematical tool that predicts the 
performance of non-tested basic models. These computer modeling and 
mathematical tools, when properly developed, can provide a means to 
predict the energy usage or efficiency characteristics of a basic model 
of a given covered product or equipment and reduce the burden and cost 
associated with testing. In the August 2022 NOPR, DOE sought specific 
feedback on the estimated costs to rate WSHP models with an AEDM. Id.
    In response to the August 2022 NOPR, MIAQ agreed that AEDMs must be 
acceptable but stated that the need for AEDMs to be representative 
requires a lot of testing by manufacturers. (MIAQ, No. 23 at p. 9) MIAQ 
commented that DOE's proposal to include WSHP's with cooling capacities 
up to 760,000 Btu/h in scope increases the time and cost associated 
with the testing required to validate the AEDM. (Id.) MIAQ recommended 
that if an AEDM-rated unit were to fail a validation test, that only 
the failed unit should be derated rather than the entire AEDM-rated 
series. (Id.) MIAQ stated that the cost to test a full 30-ton WSHP 
qualification is around $50,000-$60,000 per basic model group, and that 
developing an AEDM model with sufficient trust would require as much as 
$1 million in capital investment. (Id.)
    DOE estimates the per-manufacturer cost to develop and validate an 
AEDM to be used for all WSHP equipment with a cooling capacity less 
than 135,000 Btu/h would be $12,050 for single stage units, $14,300 for 
two stage units, and $16,550 for variable speed units. DOE estimates 
the per-manufacturer cost to develop and validate an AEDM to be used 
for all WSHPs with a cooling capacity between 135,000 Btu/h and 760,000 
Btu/h would be $26,000 for single stage units, $31,400 for two stage 
units, and $36,800 for variable speed units. DOE estimates an 
additional cost of approximately $41 per basic model for determining 
energy efficiency using the validated AEDM.\19\
---------------------------------------------------------------------------

    \19\ DOE estimated initial costs to validate an AEDM assuming 80 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering technician wage of $41 per 
hour plus the cost of third-party physical testing of two units per 
validation class (as required in 10 CFR 429.70(c)(2)(iv)). DOE 
estimated the additional per basic model cost to determine 
efficiency using an AEDM assuming 1 hour per basic model at the cost 
of an engineering technician wage of $41 per hour.
---------------------------------------------------------------------------

    DOE disagrees with MIAQ's claims on the burden of AEDM development 
for WSHPs with a cooling capacity greater than 135,000 Btu/h. As 
discussed, based on quotes from third-party test laboratories, DOE 
estimates a per-unit test cost to the amended test procedure adopted in 
appendix C1 of $10,000-$21,000 for WSHPs with a cooling capacity 
greater than 135,000 Btu/h. Per 10 CFR 429.70(c)(2), validation of an 
AEDM requires testing a minimum of only two basic models. Based on 
DOE's observation of the prevalence of use of AEDMs for WSHP and 
similar equipment for which energy conservation standards currently 
apply (i.e., for equipment with a cooling capacity no greater than 
135,000 Btu/h), DOE expects most WSHP manufacturers already have AEDMs 
for simulating WSHP performance. Further, as discussed in section 
III.A.1 of this final rule, the manufacturer literature for all 
identified model lines of WSHPs with a cooling capacity greater than 
135,000 Btu/h includes efficiency representations that are explicitly 
based on ISO 13256-1:1998, indicating that all manufacturers of this 
equipment already have the capability to generate efficiency 
representations for this equipment consistent with an industry 
consensus test procedure for WSHPs.
    Regarding the outcomes of failed DOE verification testing, in this 
final rule, DOE is not amending its regulations for AEDM verification, 
which are applicable to all equipment categories that may use AEDMs. 
DOE notes that 10 CFR 429.70(c)(5)(viii) outlines required manufacturer 
actions with regard to AEDM use if basic models certified with AEDMs 
are determined to have invalid

[[Page 84223]]

ratings. Given that most WSHP manufacturers are AHRI members and that 
DOE is incorporating by reference the prevailing industry test 
procedure that was established for use in AHRI's certification program, 
DOE expects that manufacturers will already be testing using AHRI 600-
2023 in the timeframe of any potential future energy conservation 
standards in terms of IEER and ACOP. Based on this, DOE has determined 
that the test procedure amendments adopted in this final rule are not 
expected to increase the testing burden on WSHP manufacturers that are 
AHRI members. For the minority of WSHP manufacturers that are not 
members of AHRI, the test procedure amendments may have costs 
associated with model re-rating, to the extent that the manufacturers 
would not already be testing to the updated industry test procedure. 
Additionally, DOE has determined that the test procedure amendments 
will not require manufacturers to redesign any of the covered 
equipment, will not require changes to how the equipment is 
manufactured, and will not impact the utility of the equipment.

J. Effective and Compliance Dates

    The effective date for the adopted test procedure amendments will 
be 30 days after publication of this final rule in the Federal 
Register. EPCA prescribes that, for the equipment at issue, all 
representations of energy efficiency and energy use, including those 
made on marketing materials and product labels, must be made in 
accordance with an amended test procedure, beginning 360 days after 
publication of this final rule in the Federal Register. (42 U.S.C. 
6314(d)(1))
    Starting 360 days after publication of a test procedure final rule 
in the Federal Register, and prior to the compliance date of amended 
standards for WSHPs that rely on IEER and ACOP, representations must be 
based on the test procedure in appendix C. WSHPs are not required to be 
tested according to the test procedure in appendix C1 (resulting in the 
IEER and ACOP metrics) until the compliance date of amended energy 
conservation standards denominated in terms of the IEER and ACOP 
metrics, should DOE adopt such standards.
    Any voluntary representations of IEER and ACOP made prior to the 
compliance date of amended standards for WSHPs that rely on IEER and 
ACOP must be based on the test procedure in appendix C1 starting 360 
days after publication of such a test procedure final rule in the 
Federal Register, and manufacturers may use appendix C1 to certify 
compliance with any amended standards based on IEER and ACOP, if 
adopted, prior to the applicable compliance date for those energy 
conservation standards.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866, 13563, and 14094

    Executive Order (``E.O.'') 12866, ``Regulatory Planning and 
Review,'' 58 FR 51735 (Oct. 4, 1993), as supplemented and reaffirmed by 
E.O. 13563, ``Improving Regulation and Regulatory Review,'' 76 FR 3821 
(Jan. 21, 2011) and amended by E.O. 14094, ``Modernizing Regulatory 
Review,'' 88 FR 21879 (April 11, 2023), requires agencies, to the 
extent permitted by law, to: (1) propose or adopt a regulation only 
upon a reasoned determination that its benefits justify its costs 
(recognizing that some benefits and costs are difficult to quantify); 
(2) tailor regulations to impose the least burden on society, 
consistent with obtaining regulatory objectives, taking into account, 
among other things, and to the extent practicable, the costs of 
cumulative regulations; (3) select, in choosing among alternative 
regulatory approaches, those approaches that maximize net benefits 
(including potential economic, environmental, public health and safety, 
and other advantages; distributive impacts; and equity); (4) to the 
extent feasible, specify performance objectives, rather than specifying 
the behavior or manner of compliance that regulated entities must 
adopt; and (5) identify and assess available alternatives to direct 
regulation, including providing economic incentives to encourage the 
desired behavior, such as user fees or marketable permits, or providing 
information upon which choices can be made by the public. DOE 
emphasizes as well that E.O. 13563 requires agencies to use the best 
available techniques to quantify anticipated present and future 
benefits and costs as accurately as possible. In its guidance, the 
Office of Information and Regulatory Affairs (``OIRA'') in the Office 
of Management and Budget (``OMB'') has emphasized that such techniques 
may include identifying changing future compliance costs that might 
result from technological innovation or anticipated behavioral changes. 
For the reasons stated in this preamble, this final regulatory action 
is consistent with these principles.
    Section 6(a) of E.O. 12866 also requires agencies to submit 
``significant regulatory actions'' to OIRA for review. OIRA has 
determined that this final regulatory action does not constitute a 
``significant regulatory action'' under section 3(f) of E.O. 12866. 
Accordingly, this action was not submitted to OIRA for review under 
E.O. 12866.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (``RFA'') (5 U.S.C. 601 et seq.) 
requires preparation of a final regulatory flexibility analysis 
(``FRFA'') for any rule that by law must be proposed for public 
comment, unless the agency certifies that the rule, if promulgated, 
will not have a significant economic impact on a substantial number of 
small entities. As required by E.O. 13272, ``Proper Consideration of 
Small Entities in Agency Rulemaking,'' 67 FR 53461 (August 16, 2002), 
DOE published procedures and policies on February 19, 2003, to ensure 
that the potential impacts of its rules on small entities are properly 
considered during the DOE rulemaking process. 68 FR 7990. DOE has made 
its procedures and policies available on the Office of the General 
Counsel's website: www.energy.gov/gc/office-general-counsel. DOE 
reviewed this final rule to amend the test procedure for WSHPs under 
the provisions of the RFA and the policies and procedures published on 
February 19, 2003.
    As part of the August 2022 NOPR, DOE conducted its initial 
regulatory flexibility analysis (``IRFA''). The following sections 
outline DOE's determination that this final rule does not have a 
``significant economic impact on a substantial number of small 
entities,'' and that the preparation of a FRFA is not warranted.
    DOE is amending the test procedure for WSHPs to satisfy its 
statutory obligations under EPCA. (42 U.S.C. 6314(a)(1)(A))
    In this final rule, DOE is establishing new appendices C and C1 to 
subpart F of part 431. The current DOE test procedure for WSHPs is 
relocated to appendix C without change. The amended test procedure for 
WSHPs is established in a new appendix C1, which includes the following 
amended test procedure requirements for WSHPs for measuring the updated 
efficiency metrics: (1) IEER for WSHPs using the methods from AHRI 600-
2023; and (2) ACOP using the methods specified in AHRI 600-2023. Use of 
the amended test procedure in appendix C1 will not be required until 
such time as compliance is required with amended energy conservation 
standards for WSHPs denominated in terms of IEER

[[Page 84224]]

and ACOP, should DOE adopt such standards.
    Additionally, DOE is expanding the scope of the test procedure to 
include WSHPs with capacities between 135,000 and 760,000 Btu/h, as 
well as specifying the components that must be present for testing and 
amending certain provisions related to representations and enforcement 
in 10 CFR part 429.
    DOE uses the Small Business Administration (``SBA'') small business 
size standards to determine whether manufacturers qualify as ``small 
businesses,'' which are listed by the North American Industry 
Classification System (``NAICS'').\20\ The SBA considers a business 
entity to be small business if, together with its affiliates, it 
employs less than a threshold number of workers specified in 13 CFR 
part 121. WSHP manufacturers, who produce the equipment covered by this 
rule, are classified under NAICS code 333415, ``Air-Conditioning and 
Warm Air Heating Equipment and Commercial and Industrial Refrigeration 
Equipment Manufacturing.'' In 13 CFR 121.201, the SBA sets a threshold 
of 1,250 employees or fewer for an entity to be considered as a small 
business for this category. This employee threshold includes all 
employees in a business's parent company and any other subsidiaries.
---------------------------------------------------------------------------

    \20\ The size standards are listed by NAICS code and industry 
description and are available at: www.sba.gov/document/support--
table-size-standards (Last accessed on July 16, 2021).
---------------------------------------------------------------------------

    DOE utilized the California Energy Commission's Modernized 
Appliance Efficiency Database System (``MAEDbS'') \21\ and the DOE's 
Certification Compliance Database (``CCD'') \22\ in identifying 
manufacturers. DOE screened out private labelers because original 
equipment manufacturers (``OEMs'') would likely be responsible for any 
costs associated with testing to the amended test procedure. As a 
result of this inquiry, DOE identified a total of 25 OEMs of WSHPs in 
the United States affected by this rulemaking. DOE screened out 
companies that do not meet the definition of a ``small business'' or 
are foreign owned without substantive domestic operations. DOE used 
subscription-based business information tools to determine headcount 
and revenue of each business. Of the 25 OEMs of WSHPs, DOE identified 6 
as small, domestic manufacturers.
---------------------------------------------------------------------------

    \21\ MAEDbS is available at www.cacertappliances.energy.ca.gov/Pages/Search/AdvancedSearch.aspx (Last accessed Dec. 1, 2021).
    \22\ Certified equipment in the CCD are listed by product class 
and can be accessed at www.regulations.doe.gov/certification-data/ 
(Last accessed May 1, 2023).
---------------------------------------------------------------------------

    Of the 6 small, domestic manufacturers identified, all certify 
their WSHP models in the AHRI Certification Directory for WSHPs.
    AHRI has published a new industry test standard for WSHPs, titled 
AHRI Standard 600, ``2023 Standard for Performance Rating of Water/
Brine to Air Heat Pump Equipment'' (``AHRI 600-2023''). DOE presumes 
AHRI's certification program will require rating based on AHRI 600-2023 
to develop the IEER and ACOP metrics. As a result, the test procedure 
amendments adopted in this final rule will not add any additional 
testing burden to manufacturers that already certify WSHPs to AHRI's 
certification program. Accordingly, DOE does not expect that the 
identified small business manufacturers, all of whom participate in 
AHRI's certification program, would see increased testing costs as a 
result of this rulemaking.
    Additionally, DOE notes these test procedure amendments will only 
affect voluntary representations. There is no existing energy 
conservation standard that requires manufacturer to certify to WSHP 
efficiency in terms of IEER and ACOP to DOE. Certification based on 
IEER and ACOP would only be required if and when DOE establishes energy 
conservation standards based on those metrics for WSHPs.
    Therefore, for the reasons stated in the preceding paragraphs, DOE 
concludes and certifies that the cost effects accruing from this test 
procedure final rule would not have a ``significant economic impact on 
a substantial number of small entities,'' and that the preparation of a 
FRFA is not warranted. DOE has submitted a certification and supporting 
statement of factual basis to the Chief Counsel for Advocacy of the 
Small Business Administration for review under 5 U.S.C. 605(b).

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of WSHPs must certify to DOE that their products 
comply with any applicable energy conservation standards. To certify 
compliance, manufacturers must first obtain test data for their 
products according to the DOE test procedures, including any amendments 
adopted for those test procedures. DOE has established regulations for 
the certification and recordkeeping requirements for all covered 
consumer products and commercial equipment, including WSHPs. (See 
generally 10 CFR part 429.) The collection-of-information requirement 
for the certification and recordkeeping is subject to review and 
approval by OMB under the Paperwork Reduction Act (``PRA''). This 
requirement has been approved by OMB under OMB control number 1910-
1400. Public reporting burden for the certification is estimated to 
average 35 hours per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information.
    DOE is not amending the certification or reporting requirements for 
WSHPs in this final rule. Instead, DOE may consider proposals to amend 
the certification requirements and reporting for WSHPs under a separate 
rulemaking regarding appliance and equipment certification. DOE will 
address changes to OMB Control Number 1910-1400 at that time, as 
necessary.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this final rule, DOE establishes test procedure amendments that 
it expects will be used to develop and implement future energy 
conservation standards for WSHPs. DOE has determined that this rule 
falls into a class of actions that are categorically excluded from 
review under the National Environmental Policy Act of 1969 (42 U.S.C. 
4321 et seq.) and DOE's implementing regulations at 10 CFR part 1021. 
Specifically, DOE has determined that adopting test procedures for 
measuring energy efficiency of consumer products and industrial 
equipment is consistent with activities identified in 10 CFR part 1021, 
appendix A to subpart D, A5 and A6. Accordingly, neither an 
environmental assessment nor an environmental impact statement is 
required.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4, 
1999), imposes certain requirements on agencies formulating and 
implementing policies or regulations that preempt State law or that 
have federalism implications. The Executive order requires agencies to 
examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
to carefully assess the necessity for such actions. The Executive order 
also requires agencies to have an accountable process to ensure

[[Page 84225]]

meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications. 
On March 14, 2000, DOE published a statement of policy describing the 
intergovernmental consultation process it will follow in the 
development of such regulations. 65 FR 13735. DOE examined this final 
rule and determined that it will not have a substantial direct effect 
on the States, on the relationship between the national government and 
the States, or on the distribution of power and responsibilities among 
the various levels of government. EPCA governs and prescribes Federal 
preemption of State regulations as to energy conservation for the 
products that are the subject of this final rule. States can petition 
DOE for exemption from such preemption to the extent, and based on 
criteria, set forth in EPCA. (42 U.S.C. 6316(a) and 42 U.S.C. 6316(b); 
42 U.S.C. 6297(d)) No further action is required by Executive Order 
13132.

F. Review Under Executive Order 12988

    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following requirements: (1) 
eliminate drafting errors and ambiguity; (2) write regulations to 
minimize litigation; (3) provide a clear legal standard for affected 
conduct rather than a general standard; and (4) promote simplification 
and burden reduction. Section 3(b) of Executive Order 12988 
specifically requires that Executive agencies make every reasonable 
effort to ensure that the regulation (1) clearly specifies the 
preemptive effect, if any; (2) clearly specifies any effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct while promoting simplification and burden reduction; 
(4) specifies the retroactive effect, if any; (5) adequately defines 
key terms; and (6) addresses other important issues affecting clarity 
and general draftsmanship under any guidelines issued by the Attorney 
General. Section 3(c) of Executive Order 12988 requires Executive 
agencies to review regulations in light of applicable standards in 
sections 3(a) and 3(b) to determine whether they are met or it is 
unreasonable to meet one or more of them. DOE has completed the 
required review and determined that, to the extent permitted by law, 
this final rule meets the relevant standards of Executive Order 12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (``UMRA'') 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a regulatory action resulting in a rule that may cause the 
expenditure by State, local, and Tribal governments, in the aggregate, 
or by the private sector of $100 million or more in any one year 
(adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to 
develop an effective process to permit timely input by elected officers 
of State, local, and Tribal governments on a proposed ``significant 
intergovernmental mandate,'' and requires an agency plan for giving 
notice and opportunity for timely input to potentially affected small 
governments before establishing any requirements that might 
significantly or uniquely affect small governments. On March 18, 1997, 
DOE published a statement of policy on its process for 
intergovernmental consultation under UMRA. 62 FR 12820; also available 
at www.energy.gov/gc/office-general-counsel. DOE examined this final 
rule according to UMRA and its statement of policy and determined that 
the rule contains neither an intergovernmental mandate, nor a mandate 
that may result in the expenditure of $100 million or more in any year, 
so these requirements do not apply.

H. Review Under the Treasury and General Government Appropriations Act, 
1999

    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family 
Policymaking Assessment for any rule that may affect family well-being. 
This final rule will not have any impact on the autonomy or integrity 
of the family as an institution. Accordingly, DOE has concluded that it 
is not necessary to prepare a Family Policymaking Assessment.

I. Review Under Executive Order 12630

    DOE has determined, under Executive Order 12630, ``Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights'' 53 FR 8859 (March 18, 1988), that this regulation will not 
result in any takings that might require compensation under the Fifth 
Amendment to the U.S. Constitution.

J. Review Under Treasury and General Government Appropriations Act, 
2001

    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most 
disseminations of information to the public under guidelines 
established by each agency pursuant to general guidelines issued by 
OMB. OMB's guidelines were published at 67 FR 8452 (Feb. 22, 2002), and 
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). Pursuant 
to OMB Memorandum M-19-15, Improving Implementation of the Information 
Quality Act (April 24, 2019), DOE published updated guidelines which 
are available at www.energy.gov/sites/prod/files/2019/12/f70/DOE%20Final%20Updated%20IQA%20Guidelines%20Dec%202019.pdf. DOE has 
reviewed this final rule under the OMB and DOE guidelines and has 
concluded that it is consistent with applicable policies in those 
guidelines.

K. Review Under Executive Order 13211

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001), requires Federal agencies to prepare and submit to OMB, 
a Statement of Energy Effects for any significant energy action. A 
``significant energy action'' is defined as any action by an agency 
that promulgated or is expected to lead to promulgation of a final 
rule, and that (1) is a significant regulatory action under Executive 
Order 12866, or any successor order; and (2) is likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy; or (3) is designated by the Administrator of OIRA as a 
significant energy action. For any significant energy action, the 
agency must give a detailed statement of any adverse effects on energy 
supply, distribution, or use if the regulation is implemented, and of 
reasonable alternatives to the action and their expected benefits on 
energy supply, distribution, and use.
    This regulatory action is not a significant regulatory action under 
Executive Order 12866. Moreover, it would not have a significant 
adverse effect on the supply, distribution, or use of energy, nor has 
it been designated as a significant energy action by the Administrator 
of OIRA. Therefore, it is not a significant energy action, and, 
accordingly, DOE has not prepared a Statement of Energy Effects.

[[Page 84226]]

L. Review Under Section 32 of the Federal Energy Administration Act of 
1974

    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91; 42 U.S.C. 7101), DOE must comply with section 32 of the 
Federal Energy Administration Act of 1974, as amended by the Federal 
Energy Administration Authorization Act of 1977. (15 U.S.C. 788; 
``FEAA'') Section 32 essentially provides in relevant part that, where 
a proposed rule authorizes or requires use of commercial standards, the 
notice of proposed rulemaking must inform the public of the use and 
background of such standards. In addition, section 32(c) requires DOE 
to consult with the Attorney General and the Chairman of the Federal 
Trade Commission (``FTC'') concerning the impact of the commercial or 
industry standards on competition.
    The modifications to the test procedure for WSHPs adopted in this 
final rule incorporates testing methods contained in certain sections 
of the following commercial standards: AHRI 600-2023, ANSI/ASHRAE 37-
2009, ISO 13256-1:1998, and Melinder 2010. DOE has evaluated these 
standards and is unable to conclude whether the standards fully comply 
with the requirements of section 32(b) of the FEAA (i.e., whether they 
were developed in a manner that fully provides for public 
participation, comment, and review.) DOE has consulted with both the 
Attorney General and the Chairman of the FTC about the impact on 
competition of using the methods contained in these standards and has 
received no comments objecting to their use.

M. Congressional Notification

    As required by 5 U.S.C. 801, DOE will report to Congress on the 
promulgation of this rule before its effective date. The report will 
state that it has been determined that the rule is not a ``major rule'' 
as defined by 5 U.S.C. 804(2).

N. Description of Materials Incorporated by Reference

    In this final rule, DOE incorporates by reference the following 
test standards and reference document:
    AHRI 600-2023 is an industry accepted test procedure for measuring 
the performance of water source heat pumps. AHRI 600-2023 is available 
on AHRI's website at: https://www.ahrinet.org/search-standards/ahri-600-i-p-performance-rating-waterbrine-air-heat-pump-equipment.
    ANSI/ASHRAE 37-2009 is an industry-accepted test procedure for 
measuring the performance of electrically driven unitary air-
conditioning and heat pump equipment. ANSI/ASHRAE 37-2009 is available 
on ANSI's website at: webstore.ansi.org/RecordDetail.aspx?sku=ANSI%2FASHRAE+Standard+37-2009.
    Errata sheet for ANSI/ASHRAE Standard 37-2009 dated March 27, 2019, 
specifies all of the corrections to ANSI/ASHRAE 37-2009 identified from 
the date of publication through March 27, 2019. Errata sheet for ANSI/
ASHRAE Standard 37-2009 is available on ASHRAE's website at: https://www.ashrae.org/technical-resources/standards-and-guidelines/standards-errata.
    Melinder 2010 is a reference booklet with properties of secondary 
working fluids for indirect heating and cooling systems used in air 
conditioning, heat pumps, and other applications. Melinder 2010 is 
available from the International Institute of Refrigeration website at: 
www.iifiir.org.
    ISO 13256-1:1998 is an industry-accepted test procedure for 
measuring the performance of specific water-source heat pump equipment. 
ISO 13256-1:1998 is available on ISO's website at: www.iso.org/store.html.
    The following standards are currently approved for the sections in 
which they appear in this final rule: AHRI 210/240-2008 and AHRI 340/
360-2007.

V. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects

10 CFR Part 429

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Imports, 
Incorporation by reference, Intergovernmental relations, Reporting and 
recordkeeping requirements, Small businesses.

10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Energy conservation test procedures, Incorporation by 
reference, Reporting and recordkeeping requirements.

Signing Authority

    This document of the Department of Energy was signed on November 
17, 2023, by Jeffrey Marootian, Principal Deputy Assistant Secretary 
for Energy Efficiency and Renewable Energy, pursuant to delegated 
authority from the Secretary of Energy. That document with the original 
signature and date is maintained by DOE. For administrative purposes 
only, and in compliance with requirements of the Office of the Federal 
Register, the undersigned DOE Federal Register Liaison Officer has been 
authorized to sign and submit the document in electronic format for 
publication, as an official document of the Department of Energy. This 
administrative process in no way alters the legal effect of this 
document upon publication in the Federal Register.

    Signed in Washington, DC, on November 20, 2023.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE amends parts 429 and 
431 of Chapter II of Title 10, Code of Federal Regulations as set forth 
below:

PART 429--CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER 
PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 429 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.


0
2. Amend Sec.  429.4 by:
0
a. Redesignating paragraphs (c)(4) through (6) as paragraphs (c)(5) 
through (7); and
0
b. Adding new paragraph (c)(4).
    The addition reads as follows:


Sec.  429.4  Materials incorporated by reference.

* * * * *
    (c) * * *
    (4) AHRI Standard 600-2023 (I-P) (``AHRI 600-2023''), 2023 Standard 
for Performance Rating of Water/Brine to Air Heat Pump Equipment, 
approved September 11, 2023; IBR approved for Sec.  429.43.
* * * * *

0
3. Amend Sec.  429.43 by adding paragraph (a)(3)(v) to read as follows:


Sec.  429.43  Commercial heating, ventilating, air conditioning (HVAC) 
equipment.

    (a) * * *
    (3) * * *
    (v) Water-Source Heat Pumps. When certifying to standards in terms 
of IEER and ACOP, the following provisions apply.
    (A) Individual model selection:
    (1) Representations for a basic model must be based on the least 
efficient individual model(s) distributed in commerce among all 
otherwise comparable model groups comprising

[[Page 84227]]

the basic model, except as provided in paragraph (a)(3)(v)(A)(2) of 
this section for individual models that include components listed in 
table 6 to paragraph (a)(3)(v)(A) of this section. For the purpose of 
this paragraph (a)(3)(v)(A)(1), ``otherwise comparable model group'' 
means a group of individual models distributed in commerce within the 
basic model that do not differ in components that affect energy 
consumption as measured according to the applicable test procedure 
specified at 10 CFR 431.96 other than those listed in table 6 to 
paragraph (a)(3)(v)(A) of this section. An otherwise comparable model 
group may include individual models distributed in commerce with any 
combination of the components listed in table 6 (or none of the 
components listed in table 6) to paragraph (a)(3)(v)(A) of this 
section. An otherwise comparable model group may consist of only one 
individual model.
    (2) For a basic model that includes individual models distributed 
in commerce with components listed in table 6 to paragraph (a)(3)(v)(A) 
of this section, the requirements for determining representations apply 
only to the individual model(s) of a specific otherwise comparable 
model group distributed in commerce with the least number (which could 
be zero) of components listed in table 6 to paragraph (a)(3)(v)(A) of 
this section included in individual models of the group. Testing under 
this paragraph shall be consistent with any component-specific test 
provisions specified in section 3 of appendix C1 to subpart F of 10 CFR 
part 431.

 Table 6 to Paragraph (a)(3)(v)(A)--Specific Components for Water Source
                               Heat Pumps
------------------------------------------------------------------------
             Component                           Description
------------------------------------------------------------------------
Air Economizers...................  An automatic system that enables a
                                     cooling system to supply outdoor
                                     air to reduce or eliminate the need
                                     for mechanical cooling during mild
                                     or cold weather.
Condenser Pumps/Valves/Fittings...  Additional components in the water
                                     circuit for water control or
                                     filtering.
Condenser Water Reheat............  A heat exchanger located downstream
                                     of the indoor coil that heats the
                                     supply air during cooling operation
                                     using water from the condenser coil
                                     in order to increase the ratio of
                                     moisture removal to cooling
                                     capacity provided by the equipment.
Desiccant Dehumidification          An assembly that reduces the
 Components.                         moisture content of the supply air
                                     through moisture transfer with
                                     solid or liquid desiccants.
Desuperheater.....................  A heat exchanger located downstream
                                     of the compressor on the high-
                                     pressure vapor line that moves heat
                                     to an external source, such as
                                     potable water.
Fire/Smoke/Isolation Dampers......  A damper assembly including means to
                                     open and close the damper mounted
                                     at the supply or return duct
                                     opening of the equipment.
Grill Options.....................  Special grills used to direct
                                     airflow in unique applications
                                     (such as up and away from a rear
                                     wall).
Indirect/Direct Evaporative         Water is used indirectly or directly
 Cooling of Ventilation Air.         to cool ventilation air. In a
                                     direct system the water is
                                     introduced directly into the
                                     ventilation air and in an indirect
                                     system the water is evaporated in
                                     secondary air stream and the heat
                                     is removed through a heat
                                     exchanger.
Non-Standard High-Static Indoor     The standard indoor fan motor is the
 Fan Motors.                         motor specified in the
                                     manufacturer's installation
                                     instructions for testing and shall
                                     be distributed in commerce as part
                                     of a particular model. A non-
                                     standard high-static motor is an
                                     indoor fan motor that is not the
                                     standard indoor fan motor and that
                                     is distributed in commerce as part
                                     of an individual model within the
                                     same basic model.
                                    For a non-standard high-static
                                     indoor fan motor(s) to be
                                     considered a specific component for
                                     a basic model (and thus subject to
                                     the provisions of paragraph
                                     (a)(3)(v)(A)(2) of this section),
                                     the following 2 provisions must be
                                     met:
                                    1. Non-standard high-static indoor
                                     fan motor(s) must meet the minimum
                                     allowable efficiency determined per
                                     section D.4.1 of AHRI 600-2023
                                     (incorporated by reference, see
                                     Sec.   429.4) for non-standard high-
                                     static indoor fan motors, or per
                                     section D.4.2 of AHRI 600-2023 for
                                     non-standard high-static indoor
                                     integrated fan and motor
                                     combinations.
                                    2. If the standard indoor fan motor
                                     can vary fan speed through control
                                     system adjustment of motor speed,
                                     all non-standard high-static indoor
                                     fan motors must also allow speed
                                     control (including with the use of
                                     a variable-frequency drive).
Powered Exhaust/Powered Return Air  A powered exhaust fan is a fan that
 Fans.                               transfers directly to the outside a
                                     portion of the building air that is
                                     returning to the unit, rather than
                                     allowing it to recirculate to the
                                     indoor coil and back to the
                                     building. A powered return fan is a
                                     fan that draws building air into
                                     the equipment.
Process Heat Recovery/Reclaim       A heat exchanger located inside the
 Coils/Thermal Storage.              unit that conditions the
                                     equipment's supply air using energy
                                     transferred from an external source
                                     using a vapor, gas, or liquid.
Refrigerant Reheat Coils..........  A heat exchanger located downstream
                                     of the indoor coil that heats the
                                     supply air during cooling operation
                                     using high-pressure refrigerant in
                                     order to increase the ratio of
                                     moisture removal to cooling
                                     capacity provided by the equipment.
Sound Traps/Sound Attenuators.....  An assembly of structures through
                                     which the supply air passes before
                                     leaving the equipment or through
                                     which the return air from the
                                     building passes immediately after
                                     entering the equipment for which
                                     the sound insertion loss is at
                                     least 6 dB for the 125 Hz octave
                                     band frequency range.
Steam/Hydronic Heat Coils.........  Coils used to provide supplemental
                                     heating.
Ventilation Energy Recovery System  An assembly that preconditions
 (VERS).                             outdoor air entering the equipment
                                     through direct or indirect thermal
                                     and/or moisture exchange with the
                                     exhaust air, which is defined as
                                     the building air being exhausted to
                                     the outside from the equipment.
Waterside Economizer..............  A heat exchanger located upstream of
                                     the indoor coil that conditions the
                                     supply air when system water loop
                                     conditions are favorable so as not
                                     to utilize compressor operation.
------------------------------------------------------------------------

    (B) The represented value of cooling capacity must be between 95 
percent and 100 percent of the mean of the cooling capacities measured 
for the units in the sample selected as described in paragraph 
(a)(1)(ii) of this section, or between 95 percent and 100 percent of 
the cooling capacity output simulated by the AEDM as described in 
paragraph (a)(2) of this section.
* * * * *

[[Page 84228]]


0
4. Amend Sec.  429.134 by adding paragraph (dd) to read as follows:


Sec.  429.134  Product-specific enforcement provisions.

* * * * *
    (dd) Water-Source Heat Pumps. The following provisions apply for 
assessment and enforcement testing of models subject to standards in 
terms of IEER and ACOP.
    (1) Verification of Cooling Capacity. The cooling capacity of each 
tested unit of the basic model will be measured pursuant to the test 
requirements of appendix C1 to subpart F of 10 CFR part 431. The mean 
of the measurements will be used to determine the applicable standards 
for purposes of compliance.
    (2) Specific Components. If a basic model includes individual 
models with components listed at table 6 to Sec.  429.43(a)(3)(v)(A) 
and DOE is not able to obtain an individual model with the least number 
(which could be zero) of those components within an otherwise 
comparable model group (as defined in Sec.  429.43(a)(3)(v)(A)(1)), DOE 
may test any individual model within the otherwise comparable model 
group.

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
5. The authority citation for part 431 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.


0
6. Amend Sec.  431.92 by:
0
a. Adding in alphabetical order a definition of ``Applied Coefficient 
of performance, or ACOP''; and
0
b. Revising the definitions of ``Integrated energy efficiency ratio, or 
IEER,'' and ``Water-source heat pump''.
    The addition and revisions read as follows:


Sec.  431.92  Definitions concerning commercial air conditioners and 
heat pumps.

* * * * *
    Applied Coefficient of performance, or ACOP means the ratio of the 
heating capacity to the power input, including system pump power, for 
water-source heat pumps. ACOP is expressed in watts per watt and 
determined according to appendix C1 of this subpart.
* * * * *
    Integrated energy efficiency ratio, or IEER, means a weighted 
average calculation of mechanical cooling EERs determined for four load 
levels and corresponding rating conditions, expressed in Btu/watt-hour. 
IEER is measured:
    (1) Per appendix A to this subpart for air-cooled small (>=65,000 
Btu/h), large, and very large commercial package air conditioning and 
heating equipment;
    (2) Per appendix C1 to this subpart for water-source heat pumps;
    (3) Per appendix D1 to this subpart for variable refrigerant flow 
multi-split air conditioners and heat pumps (other than air-cooled with 
rated cooling capacity less than 65,000 Btu/h); and
    (4) Per appendix G1 to this subpart for single package vertical air 
conditioners and single package vertical heat pumps.
* * * * *
    Water-source heat pump means commercial package air-conditioning 
and heating equipment that is a single-phase or three-phase reverse-
cycle heat pump that uses a circulating water loop as the heat source 
for heating and as the heat sink for cooling. The main components are a 
compressor, refrigerant-to-water heat exchanger, refrigerant-to-air 
heat exchanger, refrigerant expansion devices, refrigerant reversing 
valve, and indoor fan (except that coil-only units do not include an 
indoor fan). Such equipment includes, but is not limited to, water-to-
air water-loop heat pumps.

0
7. Amend Sec.  431.95 by:
0
a. Redesignating paragraphs (b)(6) through (10) as paragraphs (b)(7) 
through (11);
0
b. Adding new paragraph (b)(6);
0
c. In paragraph (c)(2), removing the text ``B, D1'' and adding, in its 
place, the text ``B, C1, D1'';
0
d. In paragraph (c)(3), removing the text ``appendix D1'' and adding, 
in its place, the text ``appendices C1 and D1'';
0
e. Revising paragraph (d); and
0
f. Adding paragraph (e).
    The additions and revision read as follows:


Sec.  431.95  Materials incorporated by reference.

* * * * *
    (b) * * *
    (6) AHRI Standard 600-2023 (I-P) (``AHRI 600-2023''), 2023 Standard 
for Performance Rating of Water/Brine to Air Heat Pump Equipment, AHRI-
approved September 11, 2023; IBR approved for appendix C1 to this 
subpart.
* * * * *
    (d) IIR. International Institute of Refrigeration, 177 Boulevard 
Malesherbes 75017 Paris, France; +33 (0)1 42 27 32 35; www.iifiir.org.
    (1) Properties of Secondary Working Fluids for Indirect Systems, 
including Section 2.3 Errata Sheet, Melinder, published 2010 
(``Melinder 2010''), IBR approved for appendix C1 to this subpart.
    (2) [Reserved]
    (e) ISO. International Organization for Standardization, Chemin de 
Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland; +41 22 749 01 
11; www.iso.org/store.html.
    (1) ISO Standard 13256-1 (``ISO 13256-1:1998''), ``Water-source 
heat pumps--Testing and rating for performance--Part 1: Water-to-air 
and brine-to-air heat pumps,'' approved 1998; IBR approved for appendix 
C to this subpart.
    (2) [Reserved]
* * * * *

0
8. Amend Sec.  431.96 by revising table 1 to paragraph (b) to read as 
follows:


Sec.  431.96  Uniform test method for the measurement of energy 
efficiency of commercial air conditioners and heat pumps.

* * * * *
    (b) * * *

                                Table 1 to Paragraph (b)--Test Procedures for Commercial Air Conditioners and Heat Pumps
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                               Additional test procedure
                                                            Cooling capacity or     Energy efficiency         Use tests,        provisions as indicated
          Equipment type                   Category           moisture removal          descriptor          conditions, and     in the listed paragraphs
                                                                capacity \2\                                 procedures in          of this section
--------------------------------------------------------------------------------------------------------------------------------------------------------
Small Commercial Package Air-       Air-Cooled, 3-Phase,   <65,000 Btu/h........  SEER and HSPF........  Appendix F to this    None.
 Conditioning and Heating            AC and HP.                                                           subpart \3\.
 Equipment.

[[Page 84229]]

 
                                                                                  SEER2 and HSPF2......  Appendix F1 to this   None.
                                                                                                          subpart \3\.
                                    Air-Cooled AC and HP.  >=65,000 Btu/h and     EER, IEER, and COP...  Appendix A to this    None.
                                                            <135,000 Btu/h.                               subpart.
                                    Water-Cooled and       <65,000 Btu/h........  EER..................  AHRI 210/240-2008     Paragraphs (c) and (e).
                                     Evaporatively-Cooled                                                 \1\ (omit section
                                     AC.                                                                  6.5).
                                                                                  EER..................  AHRI 340/360-2007     Paragraphs (c) and (e).
                                                                                                          \1\ (omit section
                                                                                                          6.3).
                                    Water-Source HP......  <135,000 Btu/h.......  EER and COP..........  Appendix C to this    None.
                                                                                                          subpart \3\.
                                    Water-Source HP......  <135,000 Btu/h.......  IEER and ACOP........  Appendix C1 to this   None.
                                                                                                          subpart \3\.
Large Commercial Package Air-       Air-Cooled AC and HP.  >=135,000 Btu/h and    EER, IEER and COP....  Appendix A to this    None.
 Conditioning and Heating                                   <240,000 Btu/h.                               subpart.
 Equipment.
                                    Water-Cooled and       >=135,000 Btu/h and    EER..................  AHRI 340/360-2007     Paragraphs (c) and (e).
                                     Evaporatively-Cooled   <240,000 Btu/h.                               \1\ (omit section
                                     AC.                                                                  6.3).
                                    Water-Source HP......  >=135,000 Btu/h and    EER and COP..........  Appendix C to this    None.
                                                            <240,000 Btu/h.                               subpart \3\.
                                    Water-Source HP......  >=135,000 Btu/h and    IEER and ACOP........  Appendix C1 to this   None.
                                                            <240,000 Btu/h.                               subpart \3\.
Very Large Commercial Package Air-  Air-Cooled AC and HP.  >=240,000 Btu/h and    EER, IEER and COP....  Appendix A to this    None.
 Conditioning and Heating                                   <760,000 Btu/h.                               subpart.
 Equipment.
                                    Water-Cooled and       >=240,000 Btu/h and    EER..................  AHRI 340/360-2007     Paragraphs (c) and (e).
                                     Evaporatively-Cooled   <760,000 Btu/h.                               \1\ (omit section
                                     AC.                                                                  6.3).
                                    Water-Source HP......  >=240,000 Btu/h and    EER and COP..........  Appendix C to this    None.
                                                            <760,000 Btu/h.                               subpart \3\.
                                    Water-Source HP......  >=240,000 Btu/h and    IEER and ACOP........  Appendix C1 to this   None.
                                                            <760,000 Btu/h.                               subpart \3\.
Packaged Terminal Air Conditioners  AC and HP............  <760,000 Btu/h.......  EER and COP..........  Paragraph (g) of      Paragraphs (c), (e), and
 and Heat Pumps.                                                                                          this section.         (g).
Computer Room Air Conditioners....  AC...................  <760,000 Btu/h.......  SCOP.................  Appendix E to this    None.
                                                                                                          subpart \3\.
                                                           <760,000 Btu/h or      NSenCOP..............  Appendix E1 to this   None.
                                                            <930,000 Btu/h \4\.                           subpart \3\.
Variable Refrigerant Flow Multi-    AC...................  <65,000 Btu/h (3-      SEER.................  Appendix F to this    None.
 split Systems.                                             phase).                                       subpart \3\.
                                                                                  SEER2................  Appendix F1 to this   None.
                                                                                                          subpart \3\.
Variable Refrigerant Flow Multi-    HP...................  <65,000 Btu/h (3-      SEER and HSPF........  Appendix F to this    None.
 split Systems, Air-cooled.                                 phase).                                       subpart \3\.
                                                                                  SEER2 and HSPF2......  Appendix F1 to this   None.
                                                                                                          subpart \3\.
Variable Refrigerant Flow Multi-    AC and HP............  >=65,000 Btu/h and     EER and COP..........  Appendix D to this    None.
 split Systems, Air-cooled.                                 <760,000 Btu/h.                               subpart \3\.
                                                                                  IEER and COP.........  Appendix D1 to this   None.
                                                                                                          subpart \3\.
Variable Refrigerant Flow Multi-    HP...................  <760,000 Btu/h.......  EER and COP..........  Appendix D to this    None.
 split Systems, Water-source.                                                                             subpart \3\.
                                                                                  IEER and COP.........  Appendix D1 to this   None.
                                                                                                          subpart \3\.
Single Package Vertical Air         AC and HP............  <760,000 Btu/h.......  EER and COP..........  Appendix G to this    None.
 Conditioners and Single Package                                                                          subpart \3\.
 Vertical Heat Pumps.

[[Page 84230]]

 
                                                                                  EER, IEER, and COP...  Appendix G1 to this   None.
                                                                                                          subpart \3\.
Direct Expansion-Dedicated Outdoor  All..................  <324 lbs. of moisture  ISMRE2 and ISCOP2....  Appendix B to this    None.
 Air Systems.                                               removal/hr.                                   subpart.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Incorporated by reference; see Sec.   431.95.
\2\ Moisture removal capacity applies only to direct expansion-dedicated outdoor air systems.
\3\ For equipment with multiple appendices listed in this Table 1, consult the notes at the beginning of those appendices to determine the applicable
  appendix to use for testing.
\4\ For upflow ducted and downflow floor-mounted computer room air conditioners, the test procedure in appendix E1 of this subpart applies to equipment
  with net sensible cooling capacity less than 930,000 Btu/h. For all other configurations of computer room air conditioners, the test procedure in
  appendix E1 applies to equipment with net sensible cooling capacity less than 760,000 Btu/h.

* * * * *

0
9. Add appendix C to subpart F of part 431 to read as follows:

Appendix C to Subpart F of Part 431--Uniform Test Method for Measuring 
the Energy Consumption of Water-Source Heat Pumps

    Note:  Manufacturers must use the results of testing under this 
appendix to determine compliance with the relevant standard at Sec.  
431.97 as that standard appeared in the January 1, 2023 edition of 
10 CFR parts 200-499. Specifically, representations must be based on 
testing according to either this appendix or 10 CFR 431.96 as it 
appeared in the 10 CFR parts 200-499 edition revised as of January 
1, 2023.
    Starting on November 29, 2024, voluntary representations with 
respect to energy use or efficiency of water-source heat pumps with 
cooling capacity greater than or equal to 135,000 Btu/h and less 
than 760,000 Btu/h must be based on testing according to this 
appendix. Manufacturers may also use this appendix to make voluntary 
representations with respect to energy use or efficiency prior to 
November 29, 2024.
    Starting on November 29, 2024, voluntary representations with 
respect to the integrated energy efficiency ratio (IEER) and applied 
coefficient of performance (ACOP) of water-source heat pumps must be 
based on testing according to appendix C1 of this subpart. 
Manufacturers may also use appendix C1 to make voluntary 
representations with respect to IEER and ACOP prior to November 29, 
2024.
    Starting on the compliance date for any amended energy 
conservation standards for water-source heat pumps based on IEER and 
ACOP, any representations, including compliance certifications, made 
with respect to the energy use or energy efficiency of water-source 
heat pumps must be based on testing according to appendix C1 of this 
subpart.
    Manufacturers may also certify compliance with any amended 
energy conservation standards for water-source heat pumps based on 
IEER and ACOP prior to the applicable compliance date for those 
standards, and those compliance certifications must be based on 
testing according to appendix C1 of this subpart.

1. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.95, the entire standard 
for ISO 13256-1:1998. To the extent there is a conflict between the 
terms or provisions of a referenced industry standard and this 
appendix, the appendix provisions control.

2. General

    Determine the energy efficiency ratio (EER) and coefficient of 
performance (COP) in accordance with ISO 13256-1:1998.
    Section 3 of this appendix provides additional instructions for 
determining EER and COP.

3. Additional Provisions for Equipment Set-Up

    The only additional specifications that may be used in setting up 
the basic model for testing are those set forth in the installation and 
operation manual shipped with the unit. Each unit should be set up for 
test in accordance with the manufacturer installation and operation 
manuals. Sections 3.1 through 3.2 of this appendix provide 
specifications for addressing key information typically found in the 
installation and operation manuals.
    3.1. If a manufacturer specifies a range of superheat, sub-cooling, 
and/or refrigerant pressure in its installation and operation manual 
for a given basic model, any value(s) within that range may be used to 
determine refrigerant charge or mass of refrigerant, unless the 
manufacturer clearly specifies a rating value in its installation and 
operation manual, in which case the specified rating value must be 
used.
    3.2. The airflow rate used for testing must be that set forth in 
the installation and operation manuals being shipped to the commercial 
customer with the basic model and clearly identified as that used to 
generate the DOE performance ratings. If a rated airflow value for 
testing is not clearly identified, a value of 400 standard cubic feet 
per minute (scfm) per ton must be used.

0
10. Add appendix C1 to subpart F of part 431 to read as follows:

Appendix C1 to Subpart F of Part 431--Uniform Test Method for Measuring 
the Energy Consumption of Water-Source Heat Pumps

    Note:  Prior to the compliance date of amended standards for 
water-source heat pumps that rely on integrated energy efficiency 
ratio (IEER) and applied coefficient of performance (ACOP) published 
after January 1, 2023, representations with respect to the energy 
use or energy efficiency of water-source heat pumps, including 
compliance certifications, must be based on testing according to 
appendix C of this subpart.
    Starting on November 29, 2024, voluntary representations with 
respect to the IEER and ACOP of water-source heat pumps must be 
based on testing according to this appendix. Manufacturers may also 
use this appendix to make voluntary representations with respect to 
IEER and ACOP prior to November 29, 2024.
    Starting on the compliance date for any amended energy 
conservation standards for water-source heat pumps based on IEER and 
ACOP, any representations, including compliance certifications, made 
with respect to the energy use or energy efficiency of water-source 
heat pumps must be based on testing according to this appendix.
    Manufacturers may also certify compliance with any amended 
energy conservation standards for water-source heat pumps based on 
IEER and ACOP prior to the applicable compliance date for those 
standards, and

[[Page 84231]]

those compliance certifications must be based on testing according 
to this appendix.

1. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.95 the entire standards 
for AHRI 600-2023, ANSI/ASHRAE 37-2009 (as corrected by the Errata 
sheet for ANSI/ASHRAE 37-2009), and Melinder 2010. However, certain 
enumerated provisions of AHRI 600-2023 and ASHRAE 37-2009, as listed in 
this section 1, are inapplicable.
    To the extent there is a conflict between the terms or provisions 
of a referenced industry standard and the CFR, the CFR provisions 
control.
1.1. AHRI 600-2023
    (a) Section 1 Purpose is inapplicable,
    (b) Section 2 Scope is inapplicable,
    (c) The following subsections of section 3 Definitions are 
inapplicable:
    (1) 3.2.1 (Air Economizer),
    (2) 3.2.3 (Barometric Relief Dampers),
    (3) 3.2.4 (Basic Model),
    (4) 3.2.5 (Coated Coils),
    (5) 3.2.6 (Coefficients of Performance),
    (6) 3.2.9 (Condenser Pump/Valves/Fittings),
    (7) 3.2.10 (Condenser Water Reheat),
    (8) 3.2.13 (Desiccant Dehumidification Components),
    (9) 3.2.14 (Desuperheater),
    (10) 3.2.15.1 (Energy Efficiency Ratio),
    (11) 3.2.16 (Evaporative Cooling of Ventilation Air),
    (12) 3.2.17 (Fire/Smoke/Isolation Dampers),
    (13) 3.2.19 (Fresh Air Dampers),
    (14) 3.2.21 (Grill Options),
    (15) 3.2.23 (High-effectiveness Indoor Air Filtration),
    (16) 3.2.24 (Hot Gas Bypass),
    (17) 3.2.27 (Integrated Energy Efficiency Ratio),
    (18) 3.2.28 (Low-static Heat Pump),
    (19) 3.2.35 (Power Correction Capacitors),
    (20) 3.2.36 (Powered Exhaust Air Fan),
    (21) 3.2.37 (Powered Return Air Fan),
    (22) 3.2.38 (Process Heat Recovery/Reclaim Coils/Thermal Storage),
    (23) 3.2.40 (Published Rating),
    (24) 3.2.42 (Refrigerant Reheat Coils),
    (25) 3.2.43 (Single Package Heat Pumps),
    (26) 3.2.44 (Sound Traps/Sound Attenuators),
    (27) 3.2.45 (Split System Heat Pump),
    (28) 3.2.51 (Steam/Hydronic Heat Coils),
    (29) 3.2.53 (UV Lights),
    (30) 3.2.54 (Ventilation Energy Recovery System),
    (31) 3.2.55 (Water/Brine to Air Heat Pump Equipment), and
    (32) 3.2.56 (Waterside Economizer),
    (d) The following subsections of section 6 Rating Requirements are 
inapplicable:
    (1) 6.5 (Residential Cooling Capacity and Efficiency),
    (2) 6.6 (Residential Heating Capacity and Efficiency),
    (3) 6.7 (Test Data vs Computer Simulation),
    (4) 6.8 (Rounding and Precision),
    (5) 6.9 (Uncertainty), and
    (6) 6.10 (Verification Testing),
    (e) Section 7 Minimum Data Requirements for Published Ratings is 
inapplicable
    (f) Section 8 Operating Requirements is inapplicable,
    (g) Section 9 Marking and Nameplate Data is inapplicable,
    (h) Section 10 Conformance Conditions is inapplicable,
    (i) Appendix B References--Informative is inapplicable,
    (j) Sections D.1 (Purpose), D.2 (Configuration Requirements), and 
D.3 (Optional System Features) of Appendix D Unit Configuration For 
Standard Efficiency Determination--Normative are inapplicable, and
    (k) Appendix F Example of Determination of Fan and Motor Efficiency 
for Non-standard Integrated Indoor Fan and Motors--Informative is 
inapplicable.
1.2. ANSI/ASHRAE 37-2009 (Even if Corrected by the Errata Sheet)
    (a) Section 1 Purpose is inapplicable.
    (b) Section 2 Scope is inapplicable.
    (c) Section 4 Classification is inapplicable.

2. General

    Determine integrated energy efficiency ratio (IEER) and heating 
applied coefficient of performance (ACOP) in accordance with this 
appendix and the applicable sections of AHRI 600-2023, ANSI/ASHRAE 37-
2009, and Melinder 2010. Representations of AEER, EER, and COP may 
optionally be made.
    Section 3 of this appendix provides additional instructions for 
testing. In cases where there is a conflict, the language of this 
appendix takes highest precedence, followed by AHRI 600-2023, followed 
by ANSI/ASHRAE 37-2009. Any subsequent amendment to a referenced 
document by the standard-setting organization will not affect the test 
procedure in this appendix, unless and until the test procedure is 
amended by DOE. Material is incorporated as it exists on the date of 
the approval, and a notification of any change in the incorporation 
must be published in the Federal Register.

3. Setup and Test Provisions for Specific Components

    When testing a water-source heat pump that includes any of the 
features listed in table 1 to this appendix, test in accordance with 
the setup and test provisions specified in table 1 to this appendix.

     Table 1 to Appendix C1--Setup and Test Provisions for Specific
                               Components
------------------------------------------------------------------------
                                                       Setup and test
          Component                Description           provisions
------------------------------------------------------------------------
Air Economizers.............  An automatic system   For any air
                               that enables a        economizer that is
                               cooling system to     factory-installed,
                               supply outdoor air    place the
                               to reduce or          economizer in the
                               eliminate the need    100 percent return
                               for mechanical        position and close
                               cooling during mild   and seal the
                               or cold weather.      outside air dampers
                                                     for testing. For
                                                     any modular air
                                                     economizer shipped
                                                     with the unit but
                                                     not factory-
                                                     installed, do not
                                                     install the
                                                     economizer for
                                                     testing.
Barometric Relief Dampers...  An assembly with      For any barometric
                               dampers and means     relief dampers that
                               to automatically      are factory-
                               set the damper        installed, close
                               position in a         and seal the
                               closed position and   dampers for
                               one or more open      testing. For any
                               positions to allow    modular barometric
                               venting directly to   relief dampers
                               the outside a         shipped with the
                               portion of the        unit but not
                               building air that     factory-installed,
                               is returning to the   do not install the
                               unit, rather than     dampers for
                               allowing it to        testing.
                               recirculate to the
                               indoor coil and
                               back to the
                               building.
Desiccant Dehumidification    An assembly that      Disable desiccant
 Components.                   reduces the           dehumidification
                               moisture content of   components for
                               the supply air        testing.
                               through moisture
                               transfer with solid
                               or liquid
                               desiccants.

[[Page 84232]]

 
Fire/Smoke/Isolation Dampers  A damper assembly     For any fire/smoke/
                               including means to    isolation dampers
                               open and close the    that are factory-
                               damper mounted at     installed, set the
                               the supply or         dampers in the
                               return duct opening   fully open position
                               of the equipment.     for testing. For
                                                     any modular fire/
                                                     smoke/isolation
                                                     dampers shipped
                                                     with the unit but
                                                     not factory-
                                                     installed, do not
                                                     install the dampers
                                                     for testing.
Fresh Air Dampers...........  An assembly with      For any fresh air
                               dampers and means     dampers that are
                               to set the damper     factory-installed,
                               position in a         close and seal the
                               closed and one open   dampers for
                               position to allow     testing. For any
                               air to be drawn       modular fresh air
                               into the equipment    dampers shipped
                               when the indoor fan   with the unit but
                               is operating.         not factory-
                                                     installed, do not
                                                     install the dampers
                                                     for testing.
Power Correction Capacitors.  A capacitor that      Remove power
                               increases the power   correction
                               factor measured at    capacitors for
                               the line connection   testing.
                               to the equipment.
Process Heat recovery/        A heat exchanger      Disconnect the heat
 Reclaim Coils/Thermal         located inside the    exchanger from its
 Storage.                      unit that             heat source for
                               conditions the        testing.
                               equipment's supply
                               air using energy
                               transferred from an
                               external source
                               using a vapor, gas,
                               or liquid.
Refrigerant Reheat Coils....  A heat exchanger      De-activate
                               located downstream    refrigerant reheat
                               of the indoor coil    coils for testing
                               that heats the        so as to provide
                               supply air during     the minimum (none
                               cooling operation     if possible) reheat
                               using high-pressure   achievable by the
                               refrigerant in        system controls.
                               order to increase
                               the ratio of
                               moisture removal to
                               cooling capacity
                               provided by the
                               equipment.
Steam/Hydronic Heat Coils...  Coils used to         Test with steam/
                               provide               hydronic heat coils
                               supplemental          in place but
                               heating.              providing no heat.
UV Lights...................  A lighting fixture    Turn off UV lights
                               and lamp mounted so   for testing.
                               that it shines
                               light on the indoor
                               coil, that emits
                               ultraviolet light
                               to inhibit growth
                               of organisms on the
                               indoor coil
                               surfaces, the
                               condensate drip
                               pan, and/other
                               locations within
                               the equipment.
Ventilation Energy Recovery   An assembly that      For any VERS that is
 System (VERS).                preconditions         factory-installed,
                               outdoor air           place the VERS in
                               entering the          the 100 percent
                               equipment through     return position and
                               direct or indirect    close and seal the
                               thermal and/or        outside air dampers
                               moisture exchange     and exhaust air
                               with the exhaust      dampers for
                               air, which is         testing, and do not
                               defined as the        energize any VERS
                               building air being    subcomponents
                               exhausted to the      (e.g., energy
                               outside from the      recovery wheel
                               equipment.            motors). For any
                                                     VERS module shipped
                                                     with the unit but
                                                     not factory-
                                                     installed, do not
                                                     install the VERS
                                                     for testing.
------------------------------------------------------------------------


[FR Doc. 2023-25921 Filed 12-1-23; 8:45 am]
BILLING CODE 6450-01-P