[Federal Register Volume 88, Number 106 (Friday, June 2, 2023)]
[Rules and Regulations]
[Pages 36217-36236]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-11341]


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DEPARTMENT OF ENERGY

10 CFR Part 431

[EERE-2019-BT-TP-0041]
RIN 1904-AE57


Energy Conservation Program: Test Procedure for Commercial Warm 
Air Furnaces

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 the Federal 
test procedures for commercial warm air furnaces (CWAFs) to incorporate 
the latest versions of the industry test standards that are currently 
incorporated by reference. DOE is also establishing a new metric, 
Thermal Efficiency Two (TE2), and corresponding test procedure. Use of 
the newly established test procedure would become mandatory at such 
time as compliance with amended energy conservation standards based on 
TE2 is required, should DOE adopt such standards. DOE also is adopting 
additional specifications for CWAFs with multiple flue outlets or small 
flue outlets.

DATES: The effective date of this rule is July 3, 2023. These 
amendments will be mandatory for CWAF equipment testing starting May 
28, 2024. The incorporation by reference of certain material listed in 
this rule is approved by the Director of the Federal Register on July 
3, 2023.

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 
under docket number EERE-2019-BT-TP-0041. 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-2019-BT-TP-0041. 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: Ms. Julia Hegarty, 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) 597-6737. Email: 
[email protected].
    Mr. Eric Stas, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121. 
Telephone: (202) 586-5827. Email: [email protected].

SUPPLEMENTARY INFORMATION: 

[[Page 36218]]

    DOE incorporates by reference the following industry standards into 
part 431:
    ANSI/AHRI 1500-2015 Performance Rating of Commercial Space Heating 
Boilers (``AHRI 1500-2015'');
    Copies of AHRI 1500-2015 can be obtained from the Air-Conditioning, 
Heating, and Refrigeration Institute (AHRI), 2311 Wilson Blvd., Suite 
400, Arlington, VA 22201, (703) 524-8800, or online at: 
www.ahrinet.org.
    CSA/ANSI Z21.47:21, Gas-fired central furnaces (``ANSI Z21.47-
2021'');
    ANSI/ASME PTC 19.3-1974 (R2004), Supplement to ASME Performance 
Test Codes: Part 3: Temperature Measurement, Instruments and Apparatus;
    ANSI/ASHRAE 103-2022, Method of Testing for Annual Fuel Utilization 
Efficiency of Residential Central Furnaces and Boilers (``ASHRAE 103-
2022'');
    Copies of ANSI Z21.47-2021, ANSI/ASME PTC 19.3-1974 (R2004) and 
ANSI/ASHRAE 103-2022, can be obtained from the American National 
Standards Institute (ANSI), 25 W 43rd Street, 4th Floor, New York, NY 
10036, (212) 642-4900, or online at: www.webstore.ansi.org.
    ASTM D240-09, Standard Test Method for Heat of Combustion of Liquid 
Hydrocarbon Fuels by Bomb Calorimeter;
    ASTM D396-14a, Standard Specification for Fuel Oils;
    ASTM D4809-09a, Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method);
    ASTM D5291-10, Standard Test Methods for Instrumental Determination 
of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants;
    ASTM E230/E230M-17, Standard Specification for Temperature-
Electromotive Force (emf) Tables for Standardized Thermocouples (``ASTM 
E230/E230M-17'');
    Copies of ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, ASTM D5291-
10, and ASTM E230/E230M-17 can be obtained from ASTM International, 100 
Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428, (877) 
909-2786 or online at: www.astm.org.
    NFPA 97-2003, Standard Glossary of Terms Relating to Chimneys, 
Vents, and Heat-Producing Appliances.
    Copies of NFPA 97-2003 can be obtained from the National Fire 
Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-
7471, (1-800-344-3555) or online at: www.nfpa.org.
    UL 727, Standard for Safety Oil-Fired Central Furnaces (``UL 727-
2018'');
    Copies of UL 727-2018 can be obtained from Underwriters 
Laboratories, Inc. (UL), 333 Pfingsten Road, Northbrook, IL 60062, 
(847) 272-8800 or online at: www.standardscatalog.ul.com.
    For a further discussion of these standards, see section IV.N of 
this document.

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Final Rule
III. Discussion
    A. Scope of Applicability
    B. Updates to Industry Standards
    1. UL 727
    2. HI BTS and AHRI 1500
    3. ANSI Z21.47
    4. ASHRAE 103
    C. ``Thermal Efficiency Two'' Metric
    1. Jacket Loss
    2. Part-Load Performance
    D. Electrical Energy Consumption
    E. Other Test Procedure Updates and Clarifications
    1. Flue Temperature Measurement in Models With Multiple Flue 
Outlets
    2. Flue Temperature Measurement in Models With Vent Space 
Limitations
    3. Flue Loss Determination
    4. General Approach
    F. Effective and Compliance Dates
    G. Test Procedure Costs
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Orders 12866, 13563, and 14094
    B. Review Under the Regulatory Flexibility Act
    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

    CWAFs 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)(J)) DOE's energy conservation 
standards and test procedures for CWAFs are currently prescribed at 
subpart D of part 431 of title 10 of the Code of Federal Regulations 
(CFR). The following sections discuss DOE's authority to establish and 
amend test procedures for CWAFs and relevant background information 
regarding DOE's consideration of test procedures for this equipment.

A. Authority

    The Energy Policy and Conservation Act, as amended (EPCA),\1\ among 
other things, 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 \2\ of EPCA, Public Law 94-163 (42 
U.S.C. 6311-6317, as codified) 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 covered equipment includes CWAFs, 
the subject of this final rule. (42 U.S.C. 6311(1)(J))
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    \1\ 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.
    \2\ 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), energy 
conservation standards (42 U.S.C. 6313), test procedures (42 U.S.C. 
6314), labeling provisions (42 U.S.C. 6315), 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

[[Page 36219]]

of Federal preemption in limited circumstances 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 also sets forth the criteria and 
procedures DOE must follow when prescribing or amending test procedures 
for covered equipment. Specifically, 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 (or class thereof) during a representative average 
use cycle and requires that test procedures not be unduly burdensome to 
conduct. (42 U.S.C. 6314(a)(2))
    EPCA requires that the test procedure for CWAFs 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 
Standard 90.1, ``Energy Standard for Buildings Except Low-Rise 
Residential Buildings'' (ASHRAE Standard 90.1). (42 U.S.C. 
6314(a)(4)(A)) Further, if such 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 amended test procedure would not meet the requirements in 42 
U.S.C. 6314(a)(2) and (3) related to representative use and test 
burden, in which case DOE may establish an amended test procedure that 
does satisfy those statutory provisions. (42 U.S.C. 6314(a)(4)(B) and 
(C))
    EPCA also requires that, at least once every seven years, DOE 
evaluate test procedures for each type of covered equipment, including 
CWAFs, 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)-(3))
    In addition, if DOE determines that a test procedure amendment is 
warranted, the Department 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)) As discussed further in 
section I.B of this document, in January 2023, ASHRAE released the 
latest version of ASHRAE Standard 90.1 (ASHRAE Standard 90.1-2022), 
which updated the referenced industry standards for testing CWAFs to 
reflect the most recent versions of those standards that are currently 
available, thereby triggering DOE's rulemaking obligations under EPCA. 
DOE is publishing this final rule amending the test procedure for CWAFs 
in satisfaction of both the ``ASHRAE trigger'' requirement under 42 
U.S.C. 6314(a)(4)(B) and the 7-year-lookback review requirement 
specified in EPCA under 42 U.S.C. 6314(a)(1).

B. Background

    DOE's current test procedure for CWAFs is codified at 10 CFR 
431.76, ``Uniform test method for the measurement of energy efficiency 
of commercial warm air furnaces.'' The currently applicable test 
procedure incorporates by reference two industry standards for testing 
gas-fired CWAFs: American National Standards Institute (ANSI) Z21.47-
2012, ``Standard for Gas-fired Central Furnaces'' (ANSI Z21.47-2012), 
which is used for all types of gas-fired CWAFs; and ANSI/American 
Society of Heating, Refrigeration, and Air-conditioning Engineers 
(ASHRAE) Standard 103-2007, ``Method of Testing for Annual Fuel 
Utilization Efficiency of Residential Central Furnaces and Boilers'' 
(ANSI/ASHRAE 103-2007), which is specifically used for testing 
condensing gas-fired CWAFs. 10 CFR 431.76 (c)(1), (d)(2), (e)(1), and 
(f)(1); 10 CFR 431.75(b)(1) and (c)(1). The current test procedure also 
incorporates by reference two industry standards for testing oil-fired 
CWAFs: Hydronics Institute Division of AHRI (HI) BTS-2000 Rev 06.07, 
``Method to Determine Efficiency of Commercial Space Heating Boilers'' 
(HI BTS-2000) \3\ and Underwriters Laboratories (UL) standard UL 727-
2006, ``Standard for Safety Oil-Fired Central Furnaces'' (UL 727-
2006).\4\ 10 CFR 431.76(c)(2), (d)(1), and (e)(2); 10 CFR 471.75(d)(1) 
and (e)(2).
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    \3\ DOE determined that UL 727-1994 did not provide a procedure 
for calculating the percent flue loss of the furnace, which is 
necessary in calculating the TE, and, therefore, incorporated by 
reference provisions from HI BTS-2000 to calculate the flue loss for 
oil-fired CWAFs. 69 FR 61916, 61917, 61940 (Oct. 21, 2004).
    \4\ UL 727-1994 is also incorporated by reference in 10 CFR 
431.75 but is no longer referenced in the test method specified in 
10 CFR 431.76, which references only UL 727-2006.
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    DOE most recently amended the test procedure for CWAFs in a final 
rule published in the Federal Register on July 17, 2015, which updated 
the test procedure for gas-fired CWAFs to incorporate by reference the 
latest versions of the industry standards available at the time (i.e., 
ANSI Z21.47-2012 and ANSI/ASHRAE 103-2007). 80 FR 42614 (July 2015 
final rule). At the time of the July 2015 final rule, UL 727-2006 and 
HI BTS-2000 were still the most recent versions of those industry 
standards.
    Under EPCA's seven-year-lookback provision, DOE initiated a test 
procedure rulemaking for CWAFs by publishing a request for information 
(RFI) in the Federal Register on May 5, 2020 (May 2020 RFI). 85 FR 
26626. The May 2020 RFI solicited public comments, data, and 
information on aspects of the existing DOE test procedure for CWAFs, 
including whether there are any issues with the current test procedure 
and whether it is in need of updates or revisions. Id.
    DOE published a notice of proposed rulemaking (NOPR) for the CWAFs 
test procedure in the Federal Register on February 25, 2022 that 
presented DOE's proposals to amend that test procedure. 87 FR 10726 
(February 2022 NOPR). DOE held a webinar public meeting related to this 
NOPR on March 29, 2022. DOE received comments in response to the 
February 2022 NOPR from the interested parties listed in Table I.1.

[[Page 36220]]



 Table I.1--List of Commenters With Written Submissions or Oral Comments
                  in Response to the February 2022 NOPR
------------------------------------------------------------------------
                                   Abbreviation used
          Commenter(s)            in this Final Rule    Commenter type
------------------------------------------------------------------------
AAON Inc........................  AAON..............  Manufacturer.
Air-Conditioning, Heating, and    AHRI..............  Manufacturer Trade
 Refrigeration Institute.                              Association.
American Gas Association and      AGA and APGA......  Utility Trade
 American Public Gas Association.                      Association.
Appliance Standards Awareness     Joint Advocates...  Efficiency
 Project, and Natural Resources                        Advocacy
 Defense Council.                                      Organization.
California Energy Commission....  CEC...............  Efficiency
                                                       Advocacy
                                                       Organization.
Carrier Corporation.............  Carrier...........  Manufacturer.
Daikin Comfort Technologies       Daikin............  Manufacturer.
 Manufacturing.
Lennox International Inc........  Lennox............  Manufacturer.
New York State Energy Research    NYSERDA...........  State Agency.
 and Development Authority.
Northwest Energy Efficiency       NEEA..............  Efficiency
 Alliance.                                             Advocacy
                                                       Organization.
Pacific Gas and Electric          CA IOUs...........  Utilities.
 Company, San Diego Gas and
 Electric, and Southern
 California Edison
 (collectively, the ``California
 Investor-Owned Utilities'').
Rheem Manufacturing.............  Rheem.............  Manufacturer.
------------------------------------------------------------------------

    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\5\ 
To the extent that interested parties have provided written comments 
that are substantively similar to any oral comments provided during the 
March 29, 2022 NOPR webinar public meeting, DOE cites the written 
comments throughout this final rule. For the party that provided 
substantive oral comments at the March 29, 2022 NOPR webinar public 
meeting but did not submit written comments, DOE cites the public 
meeting transcript.
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    \5\ The parenthetical reference provides a reference for 
information located in the docket of DOE's rulemaking to develop 
test procedures for CWAFs. (Docket No. EERE-2019-BT-TP-0041, 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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    Since publication of the February 2022 NOPR, DOE would note the 
following additional developments which are relevant to this rulemaking 
proceeding. As discussed, EPCA requires DOE to use industry test 
procedures developed or recognized by AHRI or ASHRAE as referenced in 
ASHRAE Standard 90.1. (42 U.S.C. 6314(a)(4)(A)-(B)) The latest update 
to ASHRAE Standard 90.1 was released in January 2023 (ASHRAE Standard 
90.1-2022). ASHRAE Standard 90.1-2022 references ANSI Z21.47-2021 as 
the test method for gas-fired CWAFs and UL 727-2018 as the test method 
for oil-fired CWAFs. This action by ASHRAE triggered DOE's rulemaking 
obligations under EPCA. As noted previously, in such cases, EPCA 
requires DOE to amend the Federal test procedure to be consistent with 
these amended industry test procedures, unless DOE determines, by rule 
published in the Federal Register and supported by clear and convincing 
evidence, that to do so would not meeting the statutory requirements 
related to representativeness and not being unduly burdensome. (42 
U.S.C. 6314(a)(4)(B)) Furthermore, EPCA also requires that, at least 
once every seven years, DOE evaluate test procedures for each class of 
covered equipment, including those for CWAFs, 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)) This 
rulemaking satisfies both of these statutory obligations.

II. Synopsis of the Final Rule

    In this final rule, DOE is amending its test procedures for CWAFs 
as follows:
    (1) Reorganize the setup and testing provisions in 10 CFR 431.76 
related to the determination of thermal efficiency (TE) into the newly 
established 10 CFR part 431, subpart D, appendix A (appendix A);
    (2) Incorporate by reference the most recent versions of the 
currently referenced industry standards:
     UL 727-2018 (previously UL 727-2006) for testing oil-fired 
CWAFs;
     AHRI 1500-2015 (previously HI BTS-2000) for performing 
fuel oil analysis and for calculating flue loss of oil-fired CWAFs;
     ANSI Z21.47-2021 (previously ANSI Z21.47-2012) for testing 
gas-fired CWAFs; and
     ANSI/ASHRAE 103-2022 (previously ANSI/ASHRAE 103-2007) for 
testing condensing gas-fired CWAFs;
    (3) Incorporate by reference the standards referenced in UL 727-
2018 (i.e., NFPA 97-2003 and ANSI/ASTM E230/230M-17), AHRI 1500-2015 
(i.e., ASTM D396-14a, ASTM D240-09, ASTM D4809-09a, and ASTM D5291-10), 
and ANSI Z21.47-2021 (i.e., ANSI/ASME PTC 19.3-1974 (R2004)) that are 
necessary for performing the DOE test procedure;
    (4) Clarify how to test units with multiple flue outlets, and units 
with flue outlets having a cross-sectional area of 3.14 square inches 
or less; and
    (5) Establish a new test procedure at 10 CFR part 431, subpart D, 
appendix B (appendix B), which generally requires testing as in 
appendix A, but which establishes a new metric, ``TE2.'' The new TE2 
metric accounts for jacket losses and part-load operation in addition 
to accounting for flue losses. Manufacturers can use appendix B to make 
voluntary representations of TE2; representations using this test 
procedure are not mandatory until such time as compliance is required 
with amended energy conservation standards based on TE2, should DOE 
adopt such standards.
    The amendments adopted in this final rule are summarized in Table 
II.1 compared to the test procedure prior to amendment, as well as the 
reason for the change.

[[Page 36221]]



                          Table II.1--Summary of Changes in the Amended Test Procedure
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    DOE test procedure prior to                                       Applicable test
             amendment                 Amended test procedures           procedure              Attribution
----------------------------------------------------------------------------------------------------------------
Referenced UL 727-2006 for testing   Incorporate by reference UL  appendix A and          Align with industry
 oil-fired CWAFs.                     727-2018 for testing oil-    appendix B.             standard update.
                                      fired CWAFs, and the
                                      standards referenced in UL
                                      727-2018 that are
                                      necessary in performing
                                      the DOE test procedure
                                      (i.e., NFPA 97-2003 and
                                      ANSI/ASTM E230/E230M-17).
Referenced HI BTS-2000 for           Incorporate by reference     appendix A and          Align with industry
 performing fuel oil analysis and     AHRI 1500-2015 for           appendix B.             standard update.
 for calculating flue loss of oil-    performing fuel oil
 fired CWAFs.                         analysis and for
                                      calculating flue loss of
                                      oil-fired CWAFs and the
                                      standards referenced in
                                      AHRI 1500-2015 that are
                                      necessary in performing
                                      the DOE test procedure
                                      (i.e., ASTM D396-14a, ASTM
                                      D240-09, ASTM D4809-09a,
                                      and ASTM D5291-10).
Referenced ANSI Z21.47-2012 for      Incorporate by reference     appendix A and          Align with industry
 testing gas-fired CWAFs.             ANSI Z21.47-2021 for         appendix B.             standard update.
                                      testing gas-fired CWAFs,
                                      and the standards
                                      referenced in ANSI Z21.47-
                                      2021 that are necessary in
                                      performing the DOE test
                                      procedure (i.e., ANSI/ASME
                                      PTC 19.3-1974 (R2004)).
Referenced ANSI/ASHRAE 103-2007 for  Incorporate by reference     appendix A and          Align with industry
 testing condensing gas-fired CWAFs.  ANSI/ASHRAE 103-2022 for     appendix B.             standard update.
                                      testing condensing gas-
                                      fired CWAFs.
Did not specify how to test units    Adds specifications for      appendix A and          Additional
 with multiple flue outlets.          units with multiple flue     appendix B.             specification to
                                      outlets. Measurements made                           improve consistency
                                      in each flue outlet shall                            and repeatability in
                                      be averaged or adjusted                              testing.
                                      using a weighted average,
                                      depending on the input
                                      capacity of the furnace
                                      module associated with
                                      each flue outlet.
Did not specify how to test units    Adds specifications to       appendix A and          Additional
 with flue outlets that are too       address units with small     appendix B.             specification to
 small to fit nine thermocouples.     flue outlets. Units with                             improve consistency
                                      flue outlets that are 3.14                           and repeatability in
                                      inches or smaller in cross-                          testing.
                                      sectional area may
                                      optionally use 5
                                      thermocouples.
Efficiency metric (TE) only          Establishes a new metric     appendix B............  Improve
 accounted for flue losses and does   (TE2) that accounts for                              representativeness.
 not account for jacket losses or     flue losses, jacket
 part-load operation.                 losses, and part-load
                                      operation.
----------------------------------------------------------------------------------------------------------------

    DOE has determined that the adopted amendments for the test 
procedure at appendix A described in section III of this document will 
not alter the measured TE of CWAFs, that the test procedures are not 
unduly burdensome to conduct, and that the test procedures more 
accurately produce test results that reflect energy efficiency, energy 
use, and estimated operating costs of CWAFs during a representative 
average use cycle.
    DOE has determined that the additional amendments for appendix B, 
which adopt TE2 as a new efficiency metric for CWAFs, do alter the 
reported efficiency of CWAFs. However, testing in accordance with the 
TE2 test procedure is not required until such time as compliance is 
required with any amended energy conservation standards based on 
appendix B. Prior to such date, voluntary representations of TE2 may be 
made, but they must be based upon use of the test procedure in appendix 
B.
    The amendments adopted in this final rule are discussed in detail 
in section III of this document.
    The effective date for the amended test procedures adopted in this 
final rule is 30 days after publication of this document in the Federal 
Register. Representations of energy use or energy efficiency must be 
based on testing in accordance with the amended test procedures 
beginning 360 days after the date of publication of this final rule in 
the Federal Register.

III. Discussion

    In the following sections, DOE describes the adopted amendments to 
the test procedures for CWAFs. DOE also discusses issues raised by 
commenters on the February 2022 NOPR, along with DOE's responses.

A. Scope of Applicability

    This rulemaking applies to CWAFs. EPCA defines ``warm air furnace'' 
as a self-contained oil-fired or gas-fired furnace designed to supply 
heated air through ducts to spaces that require it and includes 
combination warm air furnace/electric air conditioning units, but does 
not include unit heaters and duct furnaces. (42 U.S.C. 6311(11)(A)) DOE 
codified the statutory definition of ``warm air furnace'' at 10 CFR 
431.72. DOE defines a CWAF as a warm air furnace that is industrial 
equipment, and that has a capacity (rated maximum input) of 225,000 
British thermal units (Btu) per hour or more. 10 CFR 431.72.
    In response to the February 2022 NOPR, NEEA recommended that DOE 
expand the scope of CWAF coverage to include 3-phase units with a 
capacity less than 225,000 Btu/h. NEEA asserted that failing to do so 
would leave a significant portion of the CWAF market unregulated, and 
the commenter noted that DOE has recently proposed closing a similar 
regulatory gap for 3-phase small commercial air conditioners and heat 
pumps and variable refrigerant flow air conditioners and heat pumps 
with cooling capacities less than 65,000 btu/h. (NEEA, No. 24 at p. 8)
    In response, DOE notes that NEEA made the same recommendation in a 
comment submitted in response to a notice of proposed determination 
(``NOPD'') for CWAF energy conservation standards that was published in 
the Federal Register on April 26, 2022 (April 2022 NOPD). 87 FR 24455 
(See Docket No. EERE-2019-BT-STD-0042, comment 34 at p. 6) 
Subsequently, in a final determination published in the Federal 
Register on December 23, 2022 (December 2022 Final Determination), DOE 
declined to

[[Page 36222]]

amend the CWAF definition to include three-phase furnaces with 
capacities less than 225,000 Btu/h due to the limited potential to 
achieve energy savings from doing so. 87 FR 78821, 78826. DOE maintains 
its position from the December 2022 Final Determination that such 
equipment represents a small portion of the overall CWAF market, which 
at present does not provide an opportunity for significant energy 
savings.

B. Updates to Industry Standards

    As discussed, prior to the amendments adopted in this final rule, 
DOE incorporated by reference in 10 CFR part 431, subpart D, the 
following industry test procedures: UL 727-2006, HI-BTS 2000, ANSI 
Z21.47-2012, and ANSI/ASHRAE Standard 103-2007. Updated versions of 
each of these test standards have been published since they were 
incorporated into the DOE test procedure. These updated test standards 
are UL 727-2018 (update to UL 727-2006), AHRI 1500-2015 (update to HI-
BTS 2000), ANSI Z21.47-2021 (update to ANSI Z21.47-2016), and ANSI/
ASHRAE Standard 103-2022 \6\ (update to ANSI/ASHRAE Standard 103-2007).
---------------------------------------------------------------------------

    \6\ The February 2022 TP NOPR proposed to incorporate by 
reference ANSI/ASHRAE 103-2017; however, in 2022, ASHRAE published a 
more recent version of the standard, ANSI/ASHRAE 103-2022.
---------------------------------------------------------------------------

    In the February 2022 NOPR, DOE noted several differences between 
versions of the industry standards incorporated by reference at that 
time and the more recent versions of the industry standards and sought 
comment on these changes. 87 FR 10726, 10730-10735 (Feb. 25, 2022). 
Stakeholder comments in response these proposals in the February 2022 
NOPR are discussed in the following sections. In response to the 
updates to the relevant industry standards, DOE is amending the Federal 
test procedure for CWAFs to incorporate by reference in 10 CFR part 
431, subpart D, the following updated industry standards: UL 727-2018, 
AHRI 1500-2015, ANSI Z21.47-2021, and ANSI/ASHRAE 103-2022.
    As discussed, prior to the effective date of the amendments adopted 
in this final rule, the DOE test procedure for CWAFs was specified in 
10 CFR 431.76. In this final rule, DOE is reorganizing the CWAF test 
procedures into two appendixes to subpart D of 10 CFR part 431: 
appendix A (using the current TE metric) and appendix B (using the new 
TE2 metric). DOE is reorganizing the test procedures in this way 
because, as discussed in section III.C of this document, DOE is 
establishing appendix B for determining the TE2. In contrast, the 
establishment of appendix A is editorial and for reorganization 
purposes. DOE has determined that creating separate appendixes for the 
determination of the two different metrics would help clarify which 
appendix corresponds to which metric. Relevant to both appendices, DOE 
is incorporating by reference the industry standards, as discussed in 
the following sections.
1. UL 727
    The CWAF test procedure, prior to the amendments adopted in this 
final rule, required use of those procedures contained in UL 727-2006 
that are relevant to the steady-state efficiency measurement (i.e., UL 
727-2006 sections 1 through 3; 37 through 42 (except for sections 40.4 
and 40.6.2 through 40.6.7); 43.2; and 44 through 46).
    In the February 2022 NOPR, DOE proposed to amend the test procedure 
to reference UL 727-2018. 87 FR 10726, 10731 (Feb. 25, 2022). 
Additionally, DOE proposed to explicitly identify the provisions of UL 
727-2018 that are applicable to the DOE test procedure for CWAFs, 
because DOE tentatively determined that the scope section of UL 727-
2018 is not applicable since the scope of the DOE test procedure is 
defined separately in 10 CFR 431.76(a). Id.
    The February 2022 NOPR also discussed that UL 727-2018 has 
different language pertaining to temperature measurements and using 
potentiometers and thermocouples, and it also incorporates different 
ANSI references regarding these topics as compared to UL 727-2006. DOE 
tentatively determined that there was not sufficient evidence to 
indicate that the updates in UL 727-2018 would not meet the 
requirements of EPCA at 42 U.S.C. 6314(a)(2) and (3); therefore, DOE 
proposed to also incorporate by reference the updated ANSI standard 
(i.e., ANSI/ASTM E230/E230M-17) referenced by UL 727-2018. 87 FR 10726, 
10732 (Feb. 25, 2022).
    Finally, in the February 2022 NOPR, DOE discussed that UL 727-2018 
references NFPA 97M, ``Standard Glossary of Terms Relating to Chimneys, 
Gas Vents and Heat Producing Appliances'' (NFPA 97M) for definitions of 
the terms ``combustible'' and ``noncombustible'' but does not specify 
which version of NFPA 97M. DOE tentatively concluded that NFPA 97M is 
an outdated standard and that NFPA 97-2003, ``Standard Glossary of 
Terms Relating to Chimneys, Vents, and Heat-Producing Appliances'' 
(NFPA 97-2003) should be referenced for these definitions instead. 
Therefore, DOE proposed to replace references to NFPA 97M in UL 727-
2018 with references to NFPA 97-2003. Id.
    DOE received comments from Daikin, Carrier, and AHRI supporting the 
proposal to reference NFPA 97-2003 rather than NFPA 97M. (Daikin, No. 
25 at p. 1; Carrier, No. 22 at p. 2; AHRI, No. 17 at p. 2) DOE did not 
receive any comments in response to the proposals related to 
incorporating by reference UL 727-2018.
    For the reasons summarized in this document and discussed in the 
February 2022 NOPR, DOE is amending the DOE test procedure to 
incorporate by reference UL 727-2018, as well as incorporating the 
additional industry standards related to UL 727-2018.
2. HI BTS and AHRI 1500
    Prior to the amendments adopted in this final rule, DOE's test 
procedure for oil-fired CWAFs referenced sections of HI BTS-2000 that 
are relevant to fuel oil analysis and calculating percent flue loss 
(i.e., HI BTS-2000 sections 8.2.2, 11.1.4, 11.1.5, and 11.1.6.2). (See 
10 CFR 431.76(c)(2) and (e)(2) in effect as of January 1, 2022.) DOE's 
test procedure included these provisions because DOE previously 
determined that UL 727 does not provide a procedure for calculating the 
percent flue loss of the furnace, which is necessary in calculating the 
TE. Therefore, DOE incorporated by reference provisions from HI BTS-
2000 to calculate the flue loss for oil-fired CWAFs. 69 FR 61916, 
61917, 61940 (Oct. 21, 2004).
    In the February 2022 NOPR, DOE explained that in 2015, HI BTS-2000 
was replaced with AHRI 1500-2015. 87 FR 10726, 10732 (Feb. 25, 2022). 
The February 2022 NOPR also discussed that the DOE test procedure 
references fuel oil analysis requirements in HI BTS-2000 and that the 
fuel oil analysis requirements are different in AHRI 1500-2015. DOE 
tentatively determined that the differences would not impact the 
performance of a CWAF under test because the fuel oil analysis 
requirements in AHRI 1500-2015 are essentially equivalent to those in 
HI BTS-2000. As a result, DOE proposed to incorporate by reference AHRI 
1500-2015, including its fuel oil analysis specifications. 87 FR 10726, 
10733 (Feb. 25, 2022).
    In addition, in the February 2022 NOPR DOE noted that section 
11.1.4 of HI BTS-2000 requires that the carbon dioxide (CO2) 
value used in the calculation of the dry flue gas loss for

[[Page 36223]]

oil must be the measured CO2,\7\ while section C7.2.4 of 
AHRI 1500-2015 (previously section 11.1.4 in HI BTS-2000) includes the 
option to calculate CO2 using the measured oxygen 
(O2) value instead of directly measuring the CO2 
value. 87 FR 10726, 10733 (Feb. 25, 2022). DOE tentatively determined 
that calculating CO2 using a measured O2 value, 
as specified in AHRI 1500-2015, would provide results equivalent to the 
CO2 measurement currently required by the DOE test method, 
and that allowing a calculated value of CO2 would harmonize 
with the latest industry standard without increasing test burden. As 
such, DOE proposed to adopt the optional method specified in AHRI 1500-
2015 that allows for calculation CO2 using a measured 
O2 value and requested comment on this proposal. Id.
---------------------------------------------------------------------------

    \7\ The DOE test procedure at 10 CFR 431.76(d) also states that 
CO2 must be measured.
---------------------------------------------------------------------------

    AHRI supported the proposal to adopt the optional method specified 
in AHRI 1500-2015 that allows for calculation CO2 using a 
measured O2 value. (AHRI, No. 17 at p. 2) DOE did not 
receive any other comments related to its proposal to incorporate by 
reference AHRI 1500-2015. Therefore, for the reasons discussed here and 
in the February 2022 NOPR, DOE is adopting the proposals related to 
this topic made in the February 2022 NOPR.
3. ANSI Z21.47
    Prior to the amendments adopted in this final rule, the CWAF test 
procedure required the use of procedures contained in ANSI Z21.47-2012 
that are relevant to the steady-state efficiency measurement (i.e., 
sections 1.1, 2.1 through 2.6, 2.39, and 4.2.1 of ANSI Z21.47-2012).
    In the February 2022 NOPR, DOE proposed to replace the 
incorporation by reference of ANSI Z21.47-2012 with ANSI Z21.47-2021. 
87 FR 10726, 10734 (Feb. 25, 2022). DOE explained in the February 2022 
NOPR that all of the differences it had identified between the two 
versions of the standard were non-substantive and would not impact the 
test method or result. Id. However, DOE also noted that ANSI Z21.47-
2012 requires burner operating characteristics tests to be conducted 
with test gas G (i.e., butane-air), while ANSI Z21.47-2021 allows 
testing for premix burners to be done with test gas H (i.e., propane-
air) instead of test gas G at the manufacturer's option. In the 
February 2022 NOPR, DOE stated that the burner operating 
characteristics tests (including which test gas is used for them) do 
not affect the TE measurement of a CWAF and requested comment on 
whether the option provided in section 5.4a of ANSI Z21.47-2021 to use 
test gas H when performing the three burner characteristics tests would 
impact the representativeness or burden of the thermal efficiency test. 
Id.
    Lennox, Daikin, Carrier, and AHRI stated that section 5.4a of ANSI 
Z21.47-2021 is used for safety certification testing, and is unrelated 
to TE, and, therefore, recommended DOE should not reference this 
section. (Lennox, No. 19 at p. 3; Daikin, No. 25 at p. 2; Carrier, No. 
22 at p. 2; AHRI, No. 17 at p. 2) Rheem also stated that the thermal 
efficiency test is not affected by the burner operating characteristics 
test. (Rheem, Public Meeting Transcript, No. 15 at p. 11) DOE received 
no other comments related to its proposal to incorporate by reference 
ANSI Z21.47-2021.
    For the reasons discussed here and in the February 2022 NOPR, DOE 
is amending the test procedure for CWAFs to replace the incorporation 
by reference of ANSI Z21.47-2012 with ANSI Z21.47-2021. In addition, 
DOE agrees with stakeholders that section 5.4a of ANSI Z21.47-2021 does 
not impact TE, and, therefore, does not need to be referenced in the 
DOE test procedure for CWAFs. As such, DOE is not including reference 
to this section in the DOE test procedure.
4. ANSI/ASHRAE 103
    Prior to adoption of the amendments in this final rule, DOE's test 
procedure for gas-fired condensing CWAFs referenced ANSI/ASHRAE 103-
2007. In the February 2022 NOPR, DOE proposed to amend the test 
procedure by removing the reference to ANSI/ASHRAE 103-2007 and to 
instead reference ANSI/ASHRAE 103-2017, having determined that the only 
differences between the standards in the sections utilized by the CWAF 
test method were editorial in nature. 87 FR 10726, 10735. An updated 
version of ANSI/ASHRAE 103, ANSI/ASHRAE 103-2022, has since been 
released. DOE reviewed ANSI/ASHRAE 103-2022 and determined that, for 
the sections utilized in the test methods for CWAFs, there is no 
difference between the two versions of the standard.
    DOE did not receive any comments in response to its proposal to 
reference ANSI/ASHRAE 103-2017.
    Accordingly, for the reasons explained previously and because DOE 
has found there is no difference between ANSI/ASHRAE 103-2017 and ANSI/
ASHRAE 103-2022 in the sections utilized for the CWAFs test procedure, 
DOE is amending the test procedures for CWAFs to incorporate by 
reference ANSI/ASHRAE 103-2022.

C. Thermal Efficiency Two Metric

    As previously discussed, EPCA requires that the test procedures for 
CWAFs be those generally accepted industry testing procedures or rating 
procedures developed or recognized by AHRI or ASHRAE, as referenced in 
ASHRAE Standard 90.1. (42 U.S.C. 6314(a)(4)(A)) If such an industry 
test procedure or rating procedure is amended, the Secretary shall 
amend the test procedure for the product as necessary to be consistent 
with the amended industry test procedure or rating procedure unless the 
Secretary determines, by rule, published in the Federal Register and 
supported by clear and convincing evidence, that to do so would not 
meet the requirements in 42 U.S.C. 6314(a)(2) and (3) related to 
representative use and test burden.\8\ (42 U.S.C. 6314(a)(4)(B))
---------------------------------------------------------------------------

    \8\ 42 U.S.C. 6314(a)(2) requires that test procedures be 
reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs of a type of 
industrial equipment (or class thereof) during a representative 
average use cycle (as determined by the Secretary), and shall not be 
unduly burdensome to conduct. 42 U.S.C. 6314(a)(3) requires that if 
the test procedure is a procedure for determining estimated annual 
operating costs, such procedure shall provide that such costs shall 
be calculated from measurements of energy use in a representative 
average-use cycle (as determined by the Secretary), and from 
representative average unit costs of the energy needed to operate 
such equipment during such cycle.
---------------------------------------------------------------------------

    In the February 2022 NOPR, DOE tentatively determined that a test 
procedure that includes jacket loss and accounts for part-load 
operation would better produce test results that reflect energy 
efficiency, energy use, and estimated operating costs of CWAFs during a 
representative average use cycle. 87 FR 10726, 10735 (Feb. 25, 2022). 
Therefore, DOE proposed to account for these factors by establishing a 
new test procedure and metric for CWAFs, termed TE2. DOE proposed to 
establish appendix A to subpart D of 10 CFR part 431 as the test method 
for calculating TE and to establish a new appendix B to subpart D of 10 
CFR part 431, which would contain the new test method for TE2. The 
proposed test procedure at appendix B would generally adopt the same 
changes proposed for the current test procedure at appendix A but would 
additionally account for jacket losses and part load operation. 87 FR 
10726, 10735-10737 (Feb. 25, 2022). Additionally, DOE proposed that 
manufacturers would be permitted to make voluntary representations 
using TE2, and that mandatory use of the TE2 test procedure

[[Page 36224]]

would be required at such time as compliance is required with amended 
energy conservation standards based on TE2, should DOE adopt such 
standards. 87 FR 10726, 10737.
    DOE received several comments supporting DOE's proposed test 
procedure for TE2 in the February 2022 NOPR. NYSERDA generally 
supported DOE's efforts to establish the TE2 metric because it will 
improve representativeness of CWAF field performance. (NYSERDA, No. 16 
at p. 2) The Joint Advocates supported DOE's proposal to establish the 
TE2 metric, noting that the current TE metric only accounts for flue 
losses, which provides little incentive to manufacturers to adopt 
technologies that impact efficiency in the field, and not just TE. The 
Joint Advocates, therefore, stated that the TE2 metric would better 
reflect a representative average use cycle and would encourage design 
changes that would reduce energy consumption. (Joint Advocates, No. 21 
at p. 1)
    DOE also received several comments opposing the proposed test 
procedure for TE2. Lennox stated that the proposed new TE2 efficiency 
metric and methodology is a significant change that would significantly 
increase the test burden, with the commenter asserting that DOE has not 
provided supporting data that would justify these changes. Lennox 
argued that introducing such changes at the NOPR stage did not allow 
stakeholders sufficient time to fully evaluate their impacts and 
provide comment. Lennox noted that in standards rulemakings, DOE has 
declined to adopt or propose more-stringent standards due to lack of 
clear and convincing evidence that standards would be economically 
justified, and the commenter asserted that in their review of current 
CWAF test procedure and standards rulemakings, DOE has not provided 
clear and convincing evidence to establish the TE2 metric. Therefore, 
Lennox recommended that DOE should limit its test procedure amendments 
to those related to TE; otherwise, if DOE continues to pursue TE2, the 
commenter argued that DOE should revert back to the RFI stage so as to 
allow for more stakeholder engagement regarding the proposals in the 
TE2 metric. Lennox also argued against adoption of the TE2 metric 
because of the associated cumulative regulatory burden. (Lennox, No. 19 
at pp. 1-2) AHRI opposed adoption of the TE2 test procedure and metric 
because there was no reference to such a proposal for a new metric or 
any form of part-load testing in the May 2020 RFI and because DOE 
failed to include key stakeholders in the development of TE2. In 
addition, the commenter stated that there is not sufficient data or 
justification indicating that such a change to the metric would result 
in any additional energy savings. AHRI stated that the proposal to 
adopt the TE2 metric is premature, and that if DOE wishes to do so, DOE 
should go back to the RFI stage, conduct tests, and release data 
showing the new test procedure is significantly more representative 
than the current test procedure. AHRI also argued that the proposed TE2 
metric is not economically justified, and that if DOE were to adopt 
energy conservation standards based on such a metric, a crosswalk would 
run the risk of inadvertently pushing compliant units out of the market 
to produce a standard that can only be met through use of condensing 
technology. Therefore, AHRI urged DOE to continue using the current TE 
metric. (AHRI, No. 17 at pp. 2-3) Daikin agreed with AHRI on this 
issue. (Daikin, No. 25 at p. 2) AGA and APGA stated that while they are 
supportive of AHRI's comments overall, they wish to reiterate that they 
do not support DOE adopting the TE2 metric because it is not clear that 
it is more representative than the existing DOE test procedure, and 
because there is no evidence to support that the proposed TE2 test 
procedure would result in a significant change in energy savings. AGA 
and APGA also expressed concern that adopting energy conservation 
standards based on the TE2 metric would result in a standard that could 
only be met through use of condensing technology. (AGA and APGA, No. 23 
at p. 2) Carrier acknowledged that including jacket loss and part load 
operation in the thermal efficiency metric would create a more 
representative metric but asserted that more investigation and analysis 
needs to be completed before doing so. (Carrier, No. 22 at p. 2)
    In response, DOE notes that the TE metric only accounts for flue 
losses as measured while the CWAF is operating at its maximum input 
rate. Through testing of other similar appliances (e.g., consumer 
furnaces), DOE has found that the efficiency can vary when the unit 
operates at different fuel input rates; hence, test methods for such 
appliances require testing at multiple fuel input rates. Therefore, DOE 
concludes that including more than one fuel input rate will improve 
representativeness of CWAF energy efficiency as compared to only 
testing at the maximum input rate, since it will capture performance at 
additional operating points. Regarding jacket losses, DOE has found 
that CWAFs are often installed outside, and as a result, jacket losses 
can contribute significantly to overall equipment energy use. Thus, DOE 
concludes that accounting for jacket losses results in a metric that is 
more representative of CWAF performance than a metric that ignores such 
losses. Further, DOE notes that the methods proposed for determining 
TE2, which require testing to determine jacket loss and TE, are already 
in use in either industry standards (e.g., ANSI Z21.47) or DOE's own 
test method for CWAFs. Therefore, manufacturers should be familiar with 
the methods of testing such that reverting to an RFI would not be 
necessary to provide time for additional input. While DOE recognizes 
that additional testing at the minimum input rate and for jacket loss 
would increase test burden, which is discussed in more detail in 
section III.G, of this document, DOE has concluded that the benefit of 
the increased representativeness offsets the additional test burden. 
Additionally, DOE would make clear that representations using the TE2 
metric are not mandatory until such time as compliance with a standard 
denominated in terms of the TE2 metric is required, should DOE adopt 
such a standard. In this rulemaking, DOE is not amending standards to 
be based on TE2; rather, DOE is making available an optional test 
method, should manufacturers wish to make representations of efficiency 
using a more comprehensive metric. If, in a future energy conservation 
standards rulemaking, DOE considers whether to adopt an energy 
conservation standard based on the TE2 metric, DOE would further weigh 
the benefits and burdens of doing so at that time, including the 
potential additional energy savings that could be achieved through use 
of TE2 as the regulatory metric as compared to TE and whether there is 
economic justification for doing so. Based on these considerations, DOE 
has determined to adopt the proposals in the February 2022 NOPR 
regarding establishing TE2 and appendix B. The following sections 
discuss the different components of TE2 (i.e., jacket loss and part-
load operation) and specific comments from interested parties on those 
topics in more detail.
1. Jacket Loss
    In the February 2022 NOPR, DOE proposed to adopt section 5.40 of 
ANSI Z21.47-2021 for the purpose of measuring jacket loss for the TE2 
metric. 87 FR 10726, 10737 (Feb. 25, 2022). DOE also proposed to 
incorporate the jacket loss into the TE2 metric by subtracting it 
(along with flue losses) from 100 percent after applying a jacket loss 
factor to account for installation

[[Page 36225]]

location. DOE proposed to apply a jacket loss factor of 1.7 for CWAFs 
designed for indoor installation in an unheated space (i.e., isolated 
combustion system), 3.3 for CWAFs designed for outdoor installation 
(including, but not limited to, CWAFs that are weatherized, or approved 
for resistance to wind, rain, or snow), or 0 for CWAFs designed for 
installation indoors within a heated space, which is consistent with 
the values found in ANSI/ASHRAE 103-2017. Id. DOE received multiple 
comments regarding the proposed jacket loss test procedure to be used 
in determining TE2.
    NEEA, the CA IOUs, and the CEC generally supported DOE's proposals 
to include jacket loss in the TE2 metric. (NEEA, No. 24, at p. 1; CA 
IOUs, No. 20, at p. 1; CEC, No. 18, at p. 2) The CA IOUs and the CEC 
also specifically noted that the jacket loss factors are appropriate. 
(CA IOUs, No. 20, at p. 1; CEC, No. 18, at p. 2)
    Daikin, Carrier, and AHRI generally opposed DOE's proposal to 
include jacket loss in the TE2 metric. (Daikin, No. 25 at p. 2; Carrier 
No. 22 at pp. 2-3; AHRI No. 17 at p. 3) More specifically, Daikin 
stated that the burden for conducting a jacket loss test is excessive 
and is duplicative given that ASHRAE Standard 90.1 already requires a 
maximum jacket loss of 0.75 percent. (Daikin, No. 25 at p. 2) Carrier 
also stated that the jacket loss test, in particular the setup and data 
acquisition, creates additional burden on manufacturers, and that this 
increases with the size of the unit being tested. (Carrier No. 22 at 
pp. 2-3) Additionally, Carrier stated that more clarity is needed on 
how to properly run the test, as the industry has several methods to 
conduct it. (Id.) Carrier stated that while other equipment includes 
jacket loss in their calculation of efficiency (e.g., residential 
furnaces and AFUE), it is hard to scale this to CWAFs. Carrier also 
noted that with ASHRAE Standard 90.1 limiting jacket loss to 0.75 
percent, many large CWAFs may be very close to this value. 
Additionally, Carrier stated that including the 3.3 factor for 
weatherized equipment creates a sizeable impact to the thermal 
efficiency, and that if a future energy conservation standard for TE2 
is not set correctly, it would require products to operate in a range 
that condensing may occur. (Id.) AHRI stated that jacket losses are 
measured on the furnace jacket, not on the rooftop unit (RTU) 
jacket,\9\ and that furnace jackets are typically embedded far inside 
the RTU, which requires the CUAC/HP to be taken apart in order to reach 
the CWAF jacket. AHRI stated that this is an extremely burdensome task, 
and that manufacturers are already required to comply with ASHRAE 
Standard 90.1, which requires jacket loss to be less than 0.75 percent 
(although AHRI also noted that only the worst-case models are tested). 
AHRI also stated that the additional granularity of a thermal 
efficiency rating that incorporates jacket loss would be negligible. 
(AHRI No. 17 at p. 3 and 5) Rheem stated that jacket losses have to be 
below 1.5 percent for equipment sold in Canada and below 0.75 percent 
for equipment to comply with ASHRAE Standard 90.1. (Rheem, Public 
Meeting Transcript, No. 15 at p. 24)
---------------------------------------------------------------------------

    \9\ RTUs are packaged units that can include both a commercial 
unitary air conditioner (CUAC) and a CWAF and are designed for 
installation on the rooftop of commercial buildings.
---------------------------------------------------------------------------

    In response, DOE recognizes that performing an additional test to 
determine the jacket loss of a CWAF is more burdensome than not testing 
for jacket loss; however, as previously discussed, DOE has concluded 
that including jacket loss in the TE2 metric will provide a more 
representative measure of energy efficiency. DOE disagrees with AHRI 
that jacket losses would be negligible, as the percentage loss is 
included directly in the TE2 calculation. As noted by Carrier, many 
CWAFs may be close to the 0.75 percent requirement. Because the jacket 
loss percentage is multiplied by the jacket loss factor, for 
weatherized CWAFs designed to be installed outdoors (which represent 
the majority of CWAFs on the market and which have a jacket loss factor 
of 3.3) a jacket loss of 0.75 percent could result in a difference in 
TE2 of nearly 2.5 percent as compared to a unit with negligible jacket 
losses, which DOE considers significant.
    Regarding Carrier's concerns that burden increases with the size of 
the unit, DOE acknowledges that additional testing burden would be 
incurred if manufacturers decide to test according to TE2, and may 
increase more significantly for larger units. However, DOE has 
concluded that this burden would be outweighed by the anticipated 
improvement in representativeness. DOE also notes that CWAFs are 
eligible to use alternative efficiency determination methods (AEDMs,), 
which are typically used by manufacturers to mitigate burden, 
especially for testing larger commercial equipment. Further discussion 
of the testing burden posed by TE2 is included in section III.G. of 
this document.
    Although DOE recognizes that TE2 testing would be more burdensome 
as compared to TE, DOE has concluded that the TE2 test method is not 
unduly burdensome. Further discussion of the cost of testing is 
included in section III.G of this document. Additionally, DOE notes 
that the use of TE2 is optional at this time, and this final rule does 
not amend or otherwise impact the energy conservation standards for 
CWAFs. If DOE should propose amended standards in the future 
denominated in terms of the TE2 metric, DOE would consider concerns 
regarding condensing operation at that time. Lastly, DOE agrees with 
Carrier that additional clarity regarding how to conduct the test is 
warranted. In particular, DOE notes that section 5.40 of ANSI Z21.47-
2021 is not specific as to what constitutes the ``jacket.'' Therefore, 
DOE clarifies that it applies the term as defined by the CSA Group 
standard CSA P.8-2022, ``Thermal Efficiencies of Industrial and 
Commercial Gas-Fired Package Furnaces.'' CSA P.8-2022 defines the 
jacket as the surfaces surrounding the heating section of the furnace. 
The jacket includes all surfaces separating the heating section from 
the supply air, outside air, or condenser section, including the bottom 
surface separating the heating section from the basepan. DOE has 
included a description of the jacket in accordance with this definition 
in section 1.2 of appendix B.
2. Part-Load Performance
    In the February 2022 NOPR, DOE proposed to require that, for CWAFs 
with two-stage or modulating burners, the flue loss be determined at 
both the maximum and minimum input rates on the nameplate of the unit 
and that the jacket loss be determined at the maximum input rate and 
optionally at the minimum input rate. If the jacket loss were 
determined only at the maximum input rate, DOE proposed to assign an 
equivalent value at the minimum input rate. DOE proposed that TE2 would 
then be calculated as the average of the efficiencies determined at 
both the maximum and minimum input rates using the flue loss and jacket 
loss determined at each input rate, which reflects an average use case 
of 50 percent of the time operating at full load and 50 percent of the 
time operating at part-load. 87 FR 10726, 10738 (Feb. 25, 2022).
    In response to the February 2022 NOPR, AHRI stated that unlike for 
air-conditioning equipment, the range in variability in performance 
between part-load and full-load is small and that adding part-load 
performance into the

[[Page 36226]]

measurement of CWAF performance would not add to market clarity, 
especially given the burden of retesting all CWAFs on the market to 
assess performance according to such a test procedure. (AHRI, No. 17 at 
pp. 3-4)
    DOE also received comments from several stakeholders supporting the 
inclusion of part-load performance in TE2. Specifically, NEEA supported 
the inclusion of part-load operation in the proposed TE2 metric and 
noted that they have observed cases where CWAFs have had reduced 
efficiency at part-load when compared to full-load. Therefore, NEEA 
concluded that including part-load efficiency in TE2 will create a more 
representative efficiency metric. (NEEA, No. 24 at p. 6) The CA IOUs 
supported DOE's efforts to incorporate part-load operation within the 
TE2 metric and agreed with DOEs assertion in the February 2022 NOPR 
that most CWAFs have two or more stages of heating, that CWAFs spend a 
substantial time operating in part-load, and that including part-load 
performance in a TE2 metric would increase representativeness. (CA 
IOUs, No. 20 at pp. 1-2) The CEC supported including part-load 
performance in the TE2 metric and noted that CWAFs spend a large 
percentage of time in part-load operation. (CEC, No. 18 at p. 2) 
Carrier stated that part-load performance should be part of the CWAF 
test procedure. (Carrier, No. 22 at pp. 3-4)
    As discussed previously, DOE has observed during testing of similar 
products that efficiency can differ at full load as compared to part 
load and has concluded that adding testing during part-load operation 
would improve representativeness as compared to a test method that only 
requires operation at the maximum input. Therefore, DOE is adopting 
part-load testing in the TE2 metric, as initially proposed in the 
February 2022 NOPR. Regarding the need to re-test CWAFs currently rated 
to the TE metric, DOE notes that testing to determine TE2 would not be 
required until the compliance date of any energy conservation standards 
based on that metric. However, DOE concludes that the improved 
representativeness of the TE2 metric would outweigh the additional test 
burden.
    DOE also received several comments regarding the proposal to weight 
both full-load and part-load operation at 50 percent when calculating 
TE2.
    The CA IOUs encouraged DOE to continue to evaluate what full-load 
and part-load weighting factors would improve representativeness of an 
average use cycle; however, the CA IOUs stated that they do not oppose 
DOE's proposal to use 50 percent weighting factors, given the lack of 
national data on such full-load and part-load performance. (CA IOUs, 
No. 20 at p. 2) The CEC supported the DOE's proposal to equally weight 
full-load and part-load operation, but also stated that DOE should 
continue to evaluate the average use cycle of CWAFs. (CEC, No. 18 at p. 
2)
    NEEA recommended DOE reconsider the proposed weighting of low and 
high fire in the TE2 metric. NEEA presented a figure showing the 
modeled proportion of time at high fire and low fire for three 
locations in Canada (Winnipeg, Montreal, and Toronto) and two building 
types (retail and warehouse). The commenter stated that modeling has 
shown that, in colder North American climate zones (5A, 6A, and 7), the 
ratio of high fire to low fire is only close to 50/50 for warehouses in 
these cold climates, but for other use types, the ratio was closer to 
30 percent at low fire and 70 percent at high fire. NEEA stated that 
because the U.S. generally has warmer climate zones than Canada, NEEA 
would expect increased part-load operation in the U.S., and, therefore, 
it argued that a 50/50 weighting would not be representative of CWAFs 
in the U.S. (NEEA, No. 24 at pp. 6-7)
    The Joint Advocates encouraged DOE to further consider alternative 
weighting factors for full-load and part-load operation that they argue 
may be more representative of average use. The Joint Advocates also 
noted that the February 2022 NOPR refers to an estimate from NEEA that 
CWAFs spend about 10 to 20 percent of their time operating at full 
load, but that DOE did not use that estimate because the Department 
tentatively determined that the climate regions from which the estimate 
was derived were not representative of the U.S. The Joint Advocates 
urged DOE to reconsider the NEEA estimate because they understand that 
while total operating hours will vary significantly based on climate 
region, the percentage of time spent at full load is relatively 
constant across climate regions. (Joint Advocates, No. 21 at p. 2)
    Rheem stated that it is not appropriate to average the maximum and 
minimum thermal efficiencies and noted that in ANSI/ASHRAE 103 (i.e., 
the ASHRAE test method for consumer furnaces) there is a method for 
determining the weightings, and the unit does not run at the maximum 
input very often. Rheem suggested that the minimum input rate should be 
weighted more than the maximum input rate. (Rheem, Public Meeting 
Transcript, No. 15 at pp. 27-28) Daikin also stated that 50 percent 
weighting factors for full-load and part-load performance are not 
appropriate. Further, Daikin stated that the approach to weighting 
full-load and part-load operation in ANSI/ASHRAE 103 cannot be used for 
CWAFs because it was generated for residential products and the 
operational profile of commercial products is radically different. 
(Daikin, No. 25 at p. 2) Carrier commented that time spent at part-load 
is much longer than full-load, and, therefore, DOE's proposed 50 
percent weighting factor is not appropriate. Carrier recommended that 
more investigation and analysis should be performed to determine 
appropriate weighting factors that account for all types of furnaces 
(i.e., two-stage, multi-stage, and modulating). (Carrier, No. 22 at pp. 
3-4) AHRI also stated that the 50 percent weighting factors proposed by 
DOE in the February 2022 NOPR are not representative. (AHRI, No. 17 at 
p. 4)
    In response, DOE notes that the modeling presented by NEEA shows 
that in the three regions in Canada, the percentage of time a CWAF 
could operate at high fire versus low fire varied greatly, with CWAFs 
in some applications operating as little as approximately 25 percent of 
time in high fire (and 75 percent in low fire), while CWAFs in other 
applications were modeled to operate more than 70 percent of time in 
high fire (and 30 percent in low fire). Warehouses in all three 
locations were modeled to operate in high fire over 50 percent of the 
time, while retail buildings in all three locations were modeled to 
operate in high fire less than 50 percent of the time. Although NEEA 
claimed that the warmer climate in the U.S. would result in less time 
operating at full load, that is not necessarily the case as CWAFs in 
the U.S. would likely be sized differently from those in Canada due to 
the reduced heating loads. As noted by the Joint Advocates, while total 
operating hours will vary significantly based on climate region, the 
percentage of time spent at full load could remain relatively constant 
across climate regions. Although several commenters asserted that 
weighting equally at 50 percent in full-load and in part-load is not 
representative, no other commenters presented alternative data, nor is 
DOE aware of any data that would be useful to better characterize the 
appropriate weighting factors. Therefore, in this final rule, DOE is 
adopting a calculation method that weights full-load and part-load 
operation equally. Should DOE become aware of any new data regarding 
time spent operating at each input rate or data specific to different 
furnace types in the future, DOE could consider

[[Page 36227]]

revising the calculation accordingly in a subsequent rulemaking.

D. Electrical Energy Consumption

    In the February 2022 NOPR, DOE tentatively determined not to 
account for electrical energy consumption of CWAF auxiliary power 
components (e.g., controls and/or combustion blowers/fans) or the 
supply air fan in the CWAF test procedure. 87 FR 10726, 10739 (Feb. 25, 
2022). Specifically, regarding supply fan energy consumption, DOE noted 
that CWAFs are typically installed within the same cabinet as a CUAC 
and that this energy is generally accounted for in the current CUAC 
test procedure, although furnace-only operation hours are not included. 
As such, DOE tentatively determined that energy consumption during 
furnace-only operation hours would be better addressed in a future 
amendment to the CUAC test procedure. Id. Regarding auxiliary power 
consumption, DOE tentatively determined that including such power 
consumption into a CWAF performance metric would have a negligible 
impact on the measured energy efficiency of a CWAF. Id.
    In response to the February 2022 NOPR, NYSERDA encouraged DOE to 
measure fan energy consumption during furnace-only operation in the 
CWAF test procedure. (NYSERDA, No. 16 at p. 2) NEEA also recommended 
that DOE account for electricity consumption used in a CUAC, including 
fan and auxiliary energy use, that relates to CWAF energy consumption. 
In relation to DOE's tentative determination in the February 2022 NOPR 
that such energy consumption would be better addressed in a future 
amendment to the CUAC test procedure, NEEA stated such an approach 
would likely leave out the portion of the hours during the year where 
fan energy is consumed when only the CWAF is operating. NEEA stated 
that it understands DOE's desire for fan energy to ``be captured in a 
single test procedure,'' but the commenter argued that this goal is not 
achievable when cooling and heating efficiencies are regulated 
separately and also not achievable in a market as diverse as that for 
commercial HVAC. Additionally, NEEA mentioned that because fan and 
other auxiliary electrical end uses are integral to the function of any 
CWAF, it is critical than any CWAF TP and performance metric account 
for them. (NEEA, No. 24 at p. 4)
    After carefully considering these comments, DOE maintains its 
position presented in February 2022 NOPR that, at present, integrating 
the auxiliary electrical energy consumption into the efficiency metric 
for CWAF would result in negligible impact. Further, DOE also maintains 
that the fan efficiency is better accounted for in a single test method 
that addresses all fan energy consumption. Accordingly, DOE is 
proposing to address the supply air fan energy use for CWAFs, including 
during operation in heating-only mode, in the ongoing CUACs test 
procedure rulemaking. Therefore, DOE is not adopting measures of 
auxiliary electrical energy use or the electrical energy use of the 
supply air fan in this final rule.

E. Other Test Procedure Updates and Clarifications

    In the February 2022 NOPR, DOE used the terms ``vent hoods,'' 
``vent pipes,'' and ``flue outlets'' to describe the section of a CWAF 
that carries the flue gas away from the unit. DOE received a comment 
from AAON recommending DOE use the term ``flue outlets,'' because it is 
the most accurate way to describe those components. (AAON, No. 14 at p. 
1) In response, DOE has determined it appropriate to use only the term 
``flue outlet(s)'' in order to prevent confusion associated with using 
multiple terms to refer to the same outlet. As such, DOE will use the 
term ``flue outlet(s)'' in this final rule, as well as in appendix A 
and appendix B.
1. Flue Temperature Measurement in Models With Multiple Flue Outlets
    In the February 2022 NOPR, DOE proposed to add instructions to 
clarify the test method for models with multiple flue outlets. 87 FR 
10726, 10740 (Feb. 25, 2022). DOE proposed that measurements used to 
calculate TE (e.g., flue gas temperature, CO2 in flue 
gasses), be made separately for each flue outlet, and that they are 
weighted proportionally to the size of each flue outlet when 
calculating flue loss. Further, DOE proposed that test requirements, 
such as determining when equilibrium conditions occur based on the flue 
gas temperature, are determined based these weighted measurements. DOE 
noted that this proposal is predicated on the assumption that the 
amount (i.e., mass flow) of flue exhaust exiting each flue outlet is 
proportional to the outlet size. DOE recognized that ``size'' of the 
flue outlet may be measured in various ways, and, therefore, the 
Department proposed to specify that flue outlet size would be 
determined by calculating the outlet face area. DOE sought comments on 
these proposals. Id.
    Lennox stated that the size of the flue outlet may not be 
representative of the amount of flue exhaust passing through the flue 
outlet, and that DOE should consider relying on the supplemental 
testing instructions or review the input capacity for each heating 
section as the weighted average instead of the cross-sectional area of 
the flue outlet. (Lennox, No. 19 at p. 3) AHRI and Carrier supported 
clarifying how to test units with multiple flue outlets but recommended 
that the measurement and performance rating for each flue outlet should 
be based on input rating of each furnace module instead of the size of 
the flue outlet. (AHRI, No. 17 at p. 4; Carrier, No. 22 at p. 4)
    Based on these comments DOE understands that the flue outlet size 
may not directly correspond to the mass flow of flue gases exiting from 
that outlet. Consequently, DOE agrees that the fuel input rating for 
each furnace module would be a better indicator of the flue gases 
exiting the outlet for that specific module. Therefore, DOE amends the 
test procedure to clarify that for units with multiple flue gas 
outlets, the measurements used to calculate TE (e.g., flue gas 
temperature, CO2 in flue gasses) are to be made separately 
for each flue outlet, and are to be weighted proportionally to the 
input capacity associated with the furnace module.
2. Flue Temperature Measurement in Models With Vent Space Limitations
    In the February 2022 NOPR, DOE noted that section 5.16 of ANSI 
Z21.47-2021 specifies measuring the flue gas temperature using nine 
individual thermocouples placed in specific locations; however, these 
sections do not provide guidance on how to measure the flue gas 
temperature if the vent size constrains the space where the 
thermocouples are to be placed to the point that normal operation of 
the unit is inhibited when nine thermocouples are installed. 87 FR 
10726, 10740 (Feb. 25, 2022). DOE proposed to specify in the DOE test 
procedure that when testing gas-fired and oil-fired CWAFs, the flue gas 
temperatures shall be measured using nine individual thermocouples when 
the flue outlet is larger than 2 inches in diameter and may optionally 
be measured using five individual thermocouples when the flue outlet is 
2 inches or smaller in diameter, which DOE noted aligns with the 
approach in ANSI/ASHRAE 103-2017. Id. at 87 FR 10741.
    AAON stated that flue outlet geometry in CWAFs can vary in shape 
and that the diagram referenced in ANSI/ASHRAE 103 only accounts for a 
circular geometry. Consequently, AAON recommended that the number 
thermocouples needed for testing should be determined by the cross-

[[Page 36228]]

sectional area of the flue outlet. (AAON, No. 14 at p. 1) Similarly, 
Lennox noted that not all flue outlets are round, and, therefore, the 
commenter suggested that the number of thermocouples used during the 
test should be determined using the face area of the flue outlet. 
(Lennox, No. 19 at p. 3) Carrier agreed that fewer thermocouples should 
be used for units with smaller flue outlets, but also recommended the 
determination be based on cross-sectional face area, not diameter, 
since flue outlets are not always circular. (Carrier, No. 22 at p. 4) 
AHRI supported DOE's proposal that the number of thermocouples used be 
dependent on the flue outlet size; however, similar to other 
commenters, AHRI recommend that DOE base the determination of how many 
thermocouples to use on the cross-sectional area of the outlet, rather 
than the diameter. AHRI also further recommended DOE review and align 
its provisions with the requirement outlined in Figure 10 of AHRI 103. 
(AHRI, No. 17 at p. 4)
    DOE agrees that the determination of the number of thermocouples 
used in the flue outlet should be based on the area of the flue outlet, 
rather than diameter, because some flue outlets may not be circular. 
Therefore, DOE is adopting a modification to its February 2022 proposal 
so that the optional allowance to use 5 thermocouples rather than 9 in 
models with flue outlets that are 2 inches or less in diameter applies 
based on the cross-sectional area of the flue outlet. For a circular 
flue with a diameter of 2 inches, the area would be 3.14 square inches; 
thus, DOE is amending the test procedure to allow optional use of 5 
thermocouples when testing models with a flue outlet that has a cross 
sectional area of 3.14 square inches or less.
3. Flue Loss Determination
    Section 2.39 of ANSI Z21.47-2012 and section 5.40 of ANSI Z21.47-
2021 reference Annex I for the determination of flue loss that is used 
in the TE calculation. Annex I includes two methods for determining 
flue loss--one method that uses a calculation, and one method that uses 
nomographs shown in Figures I.1 and I.2 of ANSI Z21.47-2021. The 
nomograph method may only be used when the heating value, specific 
gravity, and flue gas CO2 of a CWAF fall within a specified 
range.\10\ If these conditions are met, either calculation method may 
be used. In the February 2022 NOPR, DOE proposed to require that the 
calculation method must be used when determining flue loss because the 
nomograph method is not applicable for all tests, and the calculation 
method is likely to provide better repeatability by eliminating 
subjective differences in interpreting the nomograph. 87 FR 10726, 
10741 (Feb. 25, 2022).
---------------------------------------------------------------------------

    \10\ Heating value for natural gas or propane must be 970-1100 
Btu/ft\3\ or 2466-2542 Btu/ft\3\, respectively. Specific gravity for 
natural gas or propane must be 0.57-0.70 or 1.522-15.74, 
respectively. Ultimate carbon dioxide for natural gas or propane 
must be 11.7-12.2% or 13.73-13.82%, respectively.
---------------------------------------------------------------------------

    DOE received comments from Daikin, Carrier, Lennox, Rheem, and AHRI 
that supported this proposal, and received no other comments on this 
topic. (Daikin, No. 25 at p. 3; Lennox, No. 19 at p. 3; Carrier, No. 22 
at p. 5; Rheem, Public Meeting Transcript, No. 15 at p. 21; AHRI, No. 
17 at p. 4) Based on the previously discussed rationale, DOE has 
determined that requiring the calculation method will help improve test 
repeatability. As such, DOE is requiring that the calculation method, 
not the nomograph method, from Annex I in ANSI Z21.47-2021 be used for 
the determination of flue loss.
4. General Approach
    In response to the February 2022 NOPR, DOE received several 
comments regarding its general approach to the test method for CWAFs.
    AGA and APGA recommend DOE consider implementing the 
recommendations for the recent National Academies of Sciences 
Engineering and Medicine (NASEM) on appliance standards rulemakings, 
whether for test procedures or energy conservation standards. (AGA and 
APGA, No. 23 at pp. 2-3)
    Given that this is a test procedure rulemaking for which DOE must 
meet specific statutory criteria as outlined in 42 U.S.C. 6314, the 
recommendations in the NASEM report, which pertain specifically to the 
processes by which DOE analyzes energy conservation standards, are not 
applicable. DOE will consider this comment in a separate rulemaking 
considering all covered product and covered equipment categories.
    DOE also received comments from the Joint Advocates and NEEA 
recommending that DOE consider a ``whole box'' approach for measuring 
the performance of CWAFs, similar to the approach found in CSA P.8-
2022, ``Thermal Efficiencies of Industrial and Commercial Gas-fired 
Package Furnaces.'' \11\ (Joint Advocates, No. 21 at pp. 1-2, NEEA, No. 
24 at pp. 1-5) More specifically, the Joint Advocates and NEEA stated 
that while they supported DOE's efforts to establish TE2, they 
encouraged DOE to evaluate the potential use of CSA P.8-2022. They 
asserted that CSA P.8 would more accurately represent overall 
efficiency of a CWAF because the new heating metric in that standard 
(i.e., ``total heating season coefficient of performance'') calculates 
the efficiency of a CWAF using a more holistic approach, by 
incorporating factors such as burner efficiency, total enclosure heat 
losses, fan energy consumption, and heat gains from heat recovery. Id. 
Similarly, NYSERDA also encouraged DOE to consider any forthcoming 
updates that may better measure the holistic energy use of CWAFs. 
(NYSERDA, No. 16 at p. 2)
---------------------------------------------------------------------------

    \11\ CSA P.8-2022 is available for purchase at: 
www.csagroup.org/store/product/CSA%20P.8:22/. (Last accessed Jan. 
31, 2023).
---------------------------------------------------------------------------

    As discussed in section I.A of this document, EPCA requires that 
the test procedures for CWAFs be those generally accepted industry 
testing procedures or rating procedures developed or recognized by AHRI 
or ASHRAE, as referenced in ASHRAE Standard 90.1. (42 U.S.C. 
6314(a)(4)(A)) If such an industry test procedure or rating procedure 
is amended, the Secretary shall amend the test procedure for the 
product as necessary to be consistent with the amended industry test 
procedure or rating procedure unless the Secretary determines, by rule, 
published in the Federal Register and supported by clear and convincing 
evidence, that to do so 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)) In this case, the industry test standards 
referenced by ASHRAE Standard 90.1 are ANSI Z21.47 for gas-fired CWAFs 
and UL 727 for oil-fired CWAFs. The test methods adopted in this final 
rule incorporate by reference those industry standards, and are 
generally consistent with and build upon those industry standards by 
providing clarifications or other modifications, as necessary, to meet 
the requirements of EPCA. DOE has determined that the test procedures 
for CWAFs adopted in this final rule will produce test results which 
reflect energy efficiency of CWAFs during a representative average use 
cycle, are not unduly burdensome to conduct, as required by EPCA. 
Further, DOE notes that the scope of CSA P.8-2022 indicates that the 
standard is intended to provide ``cold climate'' performance criteria 
that is representative of use in colder climates found in Canada and 
other northern locations, which may not be representative of the U.S. 
as a whole.

[[Page 36229]]

Therefore, DOE did not find it necessary to move to a test method that 
uses the approach taken by CSA P.8-2022. In response to NYSERDA, DOE 
will continue to monitor future applicable industry test standard 
updates related to CWAFs.

F. Effective and Compliance Dates

    The effective date for the adopted CWAFs test procedure amendments 
is 30 days after the date of publication of this final rule in the 
Federal Register.
    Regarding the compliance date, EPCA prescribes that 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 for CWAFs, beginning 360 days 
after the date of publication of this final rule in the Federal 
Register. (42 U.S.C. 6314(d)(1))
    To the extent the modified test procedure adopted in this final 
rule is required only for the evaluation under updated CWAF energy 
conservation standards (i.e., standards denominated in terms of the new 
TE2 metric), compliance with the amended test procedure does not 
require use of such modified test procedure provisions until the 
compliance date of such updated standards, if adopted.

G. Test Procedure Costs

    EPCA requires that the test procedures for CWAFs be those generally 
accepted industry testing procedures or rating procedures developed or 
recognized by either AHRI or ASHRAE, as referenced in ASHRAE Standard 
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))
    In this final rule, DOE is amending the test procedure for CWAFs 
for determining TE by incorporating by reference the most up-to-date 
versions of the industry test standards referenced in the DOE test 
procedure, and by providing additional detail for the test setup for 
models with multiple flue outlets and models with flue outlets having 
space limitations. DOE has determined that these amendments to the test 
procedure for determining TE would not be unduly burdensome for 
manufacturers to conduct, and that the test procedures for this 
equipment are consistent with the industry test procedure updates. DOE 
has also determined that the amendments to the test procedure for 
determining TE would improve the representativeness, accuracy, and 
reproducibility of the test results and would not be unduly burdensome 
to conduct. DOE expects that the test procedure in appendix A for 
determining TE will not increase testing costs.
    DOE is also establishing a new metric for CWAFs, TE2, and a new 
appendix B, which includes the test procedure for determining TE2. In 
the February 2022 NOPR, DOE estimated that the additional test cost due 
to the additional part-load test and jacket loss test required for the 
TE2 metric would be $2,200, compared to the DOE test procedure using 
the TE metric, which DOE estimated to be $4,200 at a third-party 
laboratory (i.e., a total estimated cost of $6,400 per tested unit for 
the amended TE2 test procedure). Therefore, assuming two units are 
tested per basic model,\12\ DOE estimated the testing cost associated 
with the newly proposed appendix B test procedure to be $12,800 per 
basic model. 87 FR 10726, 10741-10742 (Feb. 25, 2022). DOE also noted 
that in accordance with 10 CFR 429.41, CWAF manufacturers may elect to 
use an AEDM to rate models for the TE2 metric, which significantly 
reduces testing costs to industry. DOE estimated the per-manufacturer 
cost to develop and validate an AEDM to determine TE2 for CWAF 
equipment to be $17,300. DOE estimated a cost of $46 per basic model 
for determining energy efficiency using a validated AEDM.\13\ 87 FR 
10726, 10742 (Feb. 25, 2022). Additionally, DOE has determined that the 
appendix B test procedure and TE2 calculation would alter the measured 
energy efficiency of a CWAF.
---------------------------------------------------------------------------

    \12\ Per the sampling requirements specified at 10 CFR 
429.11(b), manufacturers are required to test at least two units to 
determine the rating for a basic model, except if only one unit of 
the basic model is produced.
    \13\ DOE's estimated initial cost to develop and validate an 
AEDM includes (1) 80 hours to develop the AEDM based on existing 
simulation tools; (2) an additional 16 hours to validate the AEDM 
for two basic models at the cost of an engineering calibration 
technician wage of $46 per hour; and (3) the cost of third-party 
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 calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE received multiple comments on the test cost and burden 
associated with performing the TE2 test procedure. Rheem generally 
stated that measuring jacket loss is very labor-intensive due to the 
need to take apart the unit and presents a burden to manufacturers. 
(Rheem, Public Meeting Transcript, No. 15 at pp. 23-24) AHRI asserted 
that there are external costs associated with this proposed test 
procedure change that DOE has not accounted for, including bandwidth 
limitations at laboratory facilities that would cause manufacturers to 
test internally and which could delay testing of new units while 
existing models are retested. (AHRI, No. 17 at p. 5) AHRI also asserted 
that DOE did not accurately account for the cost of performing a jacket 
loss test at full-load and part-load because determining compliance 
with ASHRAE Standard 90.1 requires that only the worst-case unit in a 
product line needs to be tested, but TE2 would require manufacturers to 
run the jacket loss test twice every time a unit is tested. AHRI also 
stated that there are no AEDMs currently available for TE2 and 
developing an AEDM is extremely costly due to the number of variables 
that need to be accounted for and modeled accurately (e.g., fan 
capacity, cabinet geometry, variation in size of the heater, and the 
inclusion of dampers, energy recovery ventilators (ERVs), and heat 
recovery ventilators (HRVs) in the airflow path). AHRI also disagreed 
with the Department's estimate that the associated rerating costs would 
be approximately $17,400, because manufacturers will need to validate 
any new AEDM by testing at least two (2) basic models, which will have 
associated manufacturing and test costs. Instead, AHRI estimated that 
the cost of the test samples alone will reach upwards of $30,000 
(without accounting for the AEDM development cost or test time), and 
that the test time must include a minimum of several days to set up for 
each sample, with laboratory time being very expensive. (Id.) Daikin 
supported AHRI's comments on this topic and added that testing cost and 
burden will increase substantially if manufacturers must assess part-
load conditions and jacket loss. Daikin noted that if ambient 
conditions must be controlled in psychometric rooms to conduct jacket 
loss testing, it could impact availability of those test rooms for 
other equipment such as commercial unitary air conditioners and heat 
pumps. (Daikin, No. 25 at p. 3) Carrier stated that DOE underestimated 
the cost to validate an AEDM, because CWAF sizes vary between 225,000 
Btu/h and 2,000,000 Btu/h (which can lead to an extremely large 
variation in cost). Carrier stated that to create an accurate

[[Page 36230]]

AEDM, a manufacturer would need to consider a ``worst case'' model, and 
that this can cost upwards of $50,000. (Carrier, No. 22 at p. 5)
    In response, DOE notes that the estimated cost of testing for TE2 
presented in the February 2022 NOPR is based on actual price quotations 
from third-party laboratories. Additionally, the estimated cost to 
develop an AEDM reflects 80 hours to develop the AEDM based on existing 
simulation tools, plus an additional 16 hours to validate the AEDM at a 
rate of $46 per hour, plus the cost to conduct the test on two units as 
required by 10 CFR 429.70(c)(2)(iv). DOE recognizes that depending on 
each individual manufacturer's approach to testing and rating their 
models (whether based on actual testing, AEDMs, or a combination of 
approaches) and the number of models they would need to rate with TE2, 
test costs could vary significantly. DOE's estimates are intended to 
represent the typical or most likely costs given the various pathways 
available for rating TE2. However, DOE recognizes that the costs could 
be higher. Although TE2 testing will be cost more than the current TE 
test method due to the need to perform jacket loss testing and testing 
at the minimum input capacity, DOE has concluded that the additional 
costs are not unduly burdensome and are justified due to the improved 
representativeness of TE2 as compared to TE. Further, because there is 
no requirement to make representations with TE2 at this time, DOE does 
not view laboratory bandwidth limitations as a significant issue. 
However, if DOE were to transition to standards based on the TE2 metric 
in the future, which would require manufacturers to make 
representations of TE2, DOE notes that it would provide a lead time 
before compliance is required, consistent with the requirements of 
EPCA,\14\ which should alleviate any laboratory bandwidth issues.
---------------------------------------------------------------------------

    \14\ Under 42 U.S.C. 6313(a)(6)(C)(iv), if DOE amends standards 
pursuant to a six-year-lookback review initiated under 42 U.S.C. 
6313(a)(6)(C)(i), amended standards apply a minimum of three years 
after publication of the amended standards. Under 42 U.S.C. 
6313(a)(6)(D)(i), if DOE amends standards pursuant to an amendment 
to ASHRAE Standard 90.1 levels, amended standards apply a minimum of 
2 years after the effective date of the minimum energy efficiency 
requirement in the amended ASHRAE Standard 90.1.
---------------------------------------------------------------------------

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 the 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 (5 U.S.C. 601 et seq.) requires 
preparation of a final regulatory flexibility analysis (FRFA) for any 
final rule where the agency was first required by law to publish a 
proposed rule 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 Executive Order 
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 under the 
provisions of the Regulatory Flexibility Act and the procedures and 
policies published on February 19, 2003.
    On February 25, 2022, DOE published in the Federal Register a 
notice of proposed rulemaking (February 2022 NOPR) proposing to update 
the references in the Federal test procedure to the most recent version 
of the relevant industry test procedures as they relate to CWAFs, as 
well as to adopt a new TE2 metric. Specifically, DOE proposed to adopt 
two appendices to 10 CFR 431.76--appendix A for determining TE and 
appendix B for determining TE2. The TE test method in appendix A is 
similar to the current method for TE, with several clarifications and 
updates to incorporate by reference the most recent versions of 
appliable industry test standards. The TE2 test method in appendix B 
builds upon the TE test method in appendix A, but also accounts for 
jacket losses and operation at the minimum input rating.
    As part of the February 2022 NOPR, DOE conducted its initial 
regulatory flexibility analysis (IRFA). 87 FR 10726, 10742-10744 (Feb. 
25, 2022). DOE used the Small Business Administration (SBA) small 
business size standards to determine whether manufacturers qualify as 
small businesses, which are listed by North American Industry 
Classification System (NAICS).\15\ The SBA considers a business entity 
to be a small business, if, together with its affiliates, it employs 
less than a threshold number of workers specified in 13 CFR part 121. 
CWAF manufacturers are classified under NAICS code 333415, ``Air-
Conditioning and Warm Air Heating Equipment and Commercial and 
Industrial Refrigeration Equipment Manufacturing.'' In 13 CFR

[[Page 36231]]

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.
---------------------------------------------------------------------------

    \15\ 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 Feb. 8, 2022).
---------------------------------------------------------------------------

    DOE relied on publicly-available databases to identify potential 
small businesses that manufacture equipment covered by this rulemaking. 
DOE utilized the California Energy Commission's Modernized Appliance 
Efficiency Database System (MAEDbS) \16\ and DOE's Certification 
Compliance Database (CCD) \17\ to identify potential small businesses 
that manufacture CWAFs covered by this rulemaking. DOE identified eight 
original equipment manufacturers (OEMs) of CWAFs affected by this 
rulemaking. DOE screened out companies that do not meet the definition 
of a ``small business'' or are foreign-owned and operated. DOE 
identified one small, domestic OEM for consideration. DOE used 
subscription-based business information tools (e.g., Dun & Bradstreet 
reports \18\) to determine headcount and revenue of the small business.
---------------------------------------------------------------------------

    \16\ MAEDbS can be accessed at cacertappliances.energy.ca.gov/Pages/ApplianceSearch.aspx (Last accessed Feb. 8, 2022).
    \17\ Certified equipment in the CCD is listed by product class 
and can be accessed at www.regulations.doe.gov/certification-data/#q=Product_Group_s%3A* (Last accessed July 15, 2021).
    \18\ The Dun & Bradstreet Hoovers subscription login is 
accessible online at app.dnbhoovers.com/ (Last accessed Feb. 8, 
2023).
---------------------------------------------------------------------------

    In the February 2022 NOPR, DOE determined the one small 
manufacturer had average annual revenues of approximately $3.3 million. 
Additionally, DOE identified four basic models from the small 
manufacturer. DOE estimated the re-rating costs for the manufacturer to 
be approximately $17,400 when making use of AEDMs. The cost for this 
small manufacturer to re-rate all basic models was estimated to be less 
than 1 percent of annual revenue. DOE also estimated the re-rating cost 
for the small manufacturer based on physical testing of all four models 
based on third-party laboratory testing. Relying on pricing quotes from 
third-party laboratories, DOE estimated costs of approximately $51,200 
for the small business. The cost for this small manufacturer to re-rate 
all basic models with physical testing was estimated to be less than 
1.6 percent of annual revenue. 87 FR 10726, 10744 (Feb. 25, 2022).
    DOE did not receive any comments on the number of small entities in 
response to the February 2022 NOPR. As discussed in section III.G of 
this document, DOE received several comments that suggested that the 
February 2022 NOPR underestimated the cost of testing for TE2 
generally. However, as discussed previously, the estimated cost of 
testing for TE2 presented in the February 2022 NOPR is based on actual 
price quotations from third-party laboratories. Additionally, the 
estimated cost to develop an AEDM reflects 80 hours to develop the AEDM 
based on existing simulation tools, plus an additional 16 hours to 
validate the AEDM at a rate of $46 per hour, plus the cost to conduct 
the test on two units as required by 10 CFR 429.70(c)(2)(iv). Although 
DOE recognizes that each individual manufacturer's approach to testing 
and rating their models (whether based on actual testing, AEDMs, or a 
combination of approaches) could cause test costs to vary 
significantly, DOE's estimates are intended to represent the typical or 
most likely costs given the various pathways available for rating TE2, 
and, therefore, DOE maintained its estimates from the February 2022 
NOPR for this final rule.
    On the basis of the de minimis compliance burden, 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 will transmit 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 CWAFs 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 CWAFs. (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 
CWAFs in this final rule. Instead, DOE may consider proposals to amend 
the certification requirements and reporting for CWAFs 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

    DOE has analyzed this regulation in accordance with the National 
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.; NEPA) and 
DOE's NEPA implementing regulations (10 CFR part 1021). In this final 
rule, DOE establishes test procedure amendments that it expects will be 
used to develop and implement future energy conservation standards for 
CWAFs. DOE has determined that this rule falls into a class of actions 
that are categorically excluded from review under NEPA and DOE's 
implementing regulations, because it is a rulemaking that interprets or 
amends an existing rule or regulation that does not change the 
environmental effect of the rule or regulation being amended. 
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, 
subpart D, appendix A, sections 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 10, 
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 
meaningful and timely input by State

[[Page 36232]]

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 has 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. 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 to amend the test procedure for measuring 
the energy efficiency of CWAFs 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

[[Page 36233]]

action, and, accordingly, DOE has not prepared a Statement of Energy 
Effects.

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 amendments to the Federal test procedure for CWAFs contained in 
this final rule adopt testing methods contained in certain sections of 
the following commercial standards: AHRI 1500-2015 (which in turn 
references ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, and ASTM D5291-
10), ANSI Z21.47-2021 (which in turn references ANSI/ASME PTC 19.3-1974 
(R2004)), ANSI/ASHRAE 103-2022, and UL 727-2018 (which in turn 
references ASTM E230/E230M-17 and NFPA 97-2003). DOE has evaluated 
these standards and is unable to conclude whether they 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 final 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:
    AHRI 1500-2015 provides instruction for how to perform fuel oil 
analysis and for how to calculate flue loss of oil-fired CWAFs.
    Copies of AHRI 1500-2015 can be obtained from the Air-Conditioning, 
Heating, and Refrigeration Institute (AHRI), 2311 Wilson Blvd., Suite 
400, Arlington, VA 22201, (703) 524-8800, or online at: 
www.ahrinet.org.
    ANSI Z21.47-2021 provides instruction for how to test gas-fired 
CWAFs.
    ANSI/ASHRAE 103-2022 provides instruction for how to test 
residential furnaces and boilers, which DOE is referencing for the 
purpose of providing instruction for testing condensing gas-fired 
CWAFs.
    ANSI/ASME PTC 19.3-1974 (R2004) is referenced by ANSI Z21.47-2021 
and specifies thermocouple requirements for when testing gas-fired 
CWAFs.
    Copies of ANSI Z21.47-2021, ANSI/ASHRAE 103-2022, and ANSI/ASME PTC 
19.3-1974 (R2004), can be obtained the from the American National 
Standards Institute (ANSI), 25 W 43rd Street, 4th Floor, New York, NY 
10036, (212) 642-4900, or online at: www.webstore.ansi.org.
    ASTM D240-09 is referenced in AHRI 1500-2015, and it contains fuel 
oil heating value requirements.
    ASTM D396-14a is referenced in AHRI 1500-2015, and it contains 
general fuel oil requirements.
    ASTM D4809-09a is referenced in AHRI 1500-2015, and it contains 
fuel oil hydrogen and carbon content requirements.
    ASTM D5291-10 is referenced in AHRI 1500-2015, and it contains fuel 
oil density requirements.
    ASTM E230/E230M-17 is referenced in UL 727-2018, and it specifies 
thermocouple requirements for when testing oil-fired CWAFs.
    Copies of ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, ASTM D5291-
10, and ASTM E230/E230M-17 can be obtained from ASTM International, 100 
Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428, (877) 
909-2786 or online at: www.astm.org.
    NFPA 97-2003 is referenced in UL 727-2018 and provides definitions 
for the terms ``combustible'' and ``noncombustible.''
    Copies of NFPA 97-2003 can be obtained from the National Fire 
Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-
7471, 1-800-344-3555 or online at: www.nfpa.org.
    UL 727-2018 provides instruction for how to test oil-fired CWAFs.
    Copies of UL 727-2018 can be obtained from Underwriters 
Laboratories, Inc. (UL), 333 Pfingsten Road, Northbrook, IL 60062, 
(847) 272-8800, or online at: www.standardscatalog.ul.com.

V. Approval of the Office of the Secretary

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

List of Subjects in 10 CFR Part 431

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

Signing Authority

    This document of the Department of Energy was signed on May 22, 
2023, by Francisco Alejandro Moreno, Acting 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 May 23, 2023.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE amends part 431 of 
chapter II of title 10, Code of Federal Regulations as set forth below:

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

0
1. 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
2. Amend Sec.  431.72 by adding in alphabetical order a definition for 
``Thermal efficiency two'' to read as follows:


Sec.  431.72  Definitions concerning commercial warm air furnaces.

* * * * *
    Thermal efficiency two for a commercial warm air furnace equals 100

[[Page 36234]]

percent minus percent flue loss and jacket loss.
* * * * *

0
3. Revise Sec.  431.75 to read as follows:


Sec.  431.75   Materials incorporated by reference.

    (a) Certain material is incorporated by reference into this subpart 
with the approval of the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other 
than that specified in this section, DOE must publish a document in the 
Federal Register and the material must be available to the public. All 
approved incorporation by reference (IBR) material is available for 
inspection at DOE, and at the National Archives and Records 
Administration (NARA). Contact DOE at: the U.S. Department of Energy, 
Office of Energy Efficiency and Renewable Energy, Building Technologies 
Program, 1000 Independence Ave. SW, EE-5B, Washington, DC 20585, (202) 
586-9127, [email protected], www.energy.gov/eere/buildings/building-technologies-office. For information on the availability of this 
material at NARA, visit: www.archives.gov/federal-register/cfr/ibr-locations.html or email: [email protected]. The material may be 
obtained from the sources in the following paragraphs of this section.
    (b) AHRI. Air-Conditioning, Heating, and Refrigeration Institute, 
2311 Wilson Blvd., Suite 400, Arlington, VA 22201, (703) 524-8800, or 
online at: www.ahrinet.org.
    (1) ANSI/AHRI 1500-2015 (``AHRI 1500-2015''), Performance Rating of 
Commercial Space Heating Boilers, ANSI-approved November 28, 2014; IBR 
approved for appendix A to this subpart.
    (2) [Reserved]
    (c) ANSI. American National Standards Institute. 25 W 43rd Street, 
4th Floor, New York, NY 10036. (212) 642-4900 or online at: 
www.ansi.org.
    (1) CSA/ANSI Z21.47:21, (``ANSI Z21.47-2021''), Gas-fired central 
furnaces, ANSI-approved April 21, 2021; IBR approved for appendices A 
and B to this subpart.
    (2) [Reserved]
    (d) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers Inc., 180 Technology Parkway NW, Peachtree 
Corners, Georgia 30092, (404) 636-8400, or online at: www.ashrae.org.
    (1) ANSI/ASHRAE 103-2022 (``ASHRAE 103-2022''), Method of Testing 
for Annual Fuel Utilization Efficiency of Residential Central Furnaces 
and Boilers, approved January 10, 2022; IBR approved for appendix A to 
this subpart.
    (2) [Reserved]
    (e) ASME. American Society of Mechanical Engineers, Service Center, 
22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007, (973) 882-1170, or 
online at: www.asme.org.
    (1) ANSI/ASME PTC 19.3-1974 (R2004), Supplement to ASME Performance 
Test Codes: Part 3: Temperature Measurement, Instruments and Apparatus, 
reaffirmed 2004; IBR approved for appendix A to this subpart.
    (2) [Reserved]
    (f) ASTM. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, 
West Conshohocken, PA 19428, (877) 909-2786, or online at: 
www.astm.org/.
    (1) ASTM D240-09, Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter, approved July 1, 2009; 
IBR approved for appendix A to this subpart.
    (2) ASTM D396-14a, Standard Specification for Fuel Oils, approved 
October 1, 2014; IBR approved for appendix A to this subpart.
    (3) ASTM D4809-09a, Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method); 
approved September 1, 2009; IBR approved for appendix A to this 
subpart.
    (4) ASTM D5291-10, Standard Test Methods for Instrumental 
Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products 
and Lubricants, approved May 1, 2010; IBR approved for appendix A to 
this subpart.
    (5) ASTM E230/E230M-17 (``ASTM E230/E230M-17''), Standard 
Specification for Temperature-Electromotive Force (emf) Tables for 
Standardized Thermocouples, approved November 1, 2017; IBR approved for 
appendix A to this subpart.
    (g) NFPA. National Fire Protection Association, 1 Batterymarch 
Park, Quincy, MA 02169-7471, 1-800-344-3555, or online at: 
www.nfpa.org.
    (1) NFPA 97 (``NFPA 97-2003''), Standard Glossary of Terms Relating 
to Chimneys, Vents, and Heat-Producing Appliances; copyright 2023; IBR 
approved for appendix A to this subpart.
    (2) [Reserved]
    (h) UL. Underwriters Laboratories, Inc., 333 Pfingsten Road, 
Northbrook, IL 60062, (847) 272-8800, or online at: www.ul.com.
    (1) UL 727 (``UL 727-2018''), Standard for Safety Oil-Fired Central 
Furnaces, Tenth Edition, published January 31, 2018; IBR approved for 
appendix A to this subpart.
    (2) [Reserved]

0
4. Revise Sec.  431.76 to read as follows:


Sec.  431.76   Uniform test method for the measurement of energy 
efficiency of commercial warm air furnaces.

    (a) Scope. This section prescribes the test requirements used to 
measure the energy efficiency of commercial warm air furnaces with a 
rated maximum input of 225,000 Btu per hour or more.
    (b) Testing and calculations--(1) Thermal efficiency. Test in 
accordance with appendix A to subpart D of this part when making 
representations of thermal efficiency.
    (2) Thermal efficiency two. Test in accordance with appendix B to 
subpart D of this part when making representations of thermal 
efficiency two.

0
5. Appendix A to subpart D of part 431 is added to read as follows:

Appendix A to Subpart D of Part 431--Uniform Test Method for 
Measurement of the Energy Efficiency of Commercial Warm Air Furnaces 
(Thermal Efficiency)

    Note:  On and after May 28, 2024, any representations made with 
respect to the energy use or efficiency of commercial warm air 
furnaces must be made in accordance with the results of testing 
pursuant to this section. At that time, manufacturers must use the 
relevant procedures specified in this appendix, which reference ANSI 
Z21.47-2021, ASHRAE 103-2022, UL 727-2018, or AHRI 1500-2015. On and 
after July 3, 2023 and prior to May 28, 2024, manufacturers must 
test commercial warm air furnaces in accordance with this appendix 
or 10 CFR 431.76 as it appeared on January 1, 2023. DOE notes that, 
because testing under this section is required as of May 28, 2024, 
manufacturers may wish to begin using this amended test procedure as 
soon as possible. Any representations made with respect to the 
energy use or efficiency of such commercial warm air furnaces must 
be made in accordance with whichever version is selected.
    Manufacturers must use the results of testing under appendix B 
to this subpart to determine compliance with any standards for 
commercial warm air furnaces that use the thermal efficiency 2 (TE2) 
metric.

    0. Incorporation by reference.
    In Sec.  431.75, DOE incorporated by reference the entire 
standard for AHRI 1500-2015, ANSI Z21.47-2021, ASHRAE 103-2022, ASME 
PTC 19.3-1974 (R2004), ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, 
ASTM D5291-10, ASTM E230/E230M-17, NFPA 97-2003, and UL 727-2018. 
However, for standards AHRI 1500-2015, ANSI Z21.47-2021, ASHRAE 103-
2022, and UL 727-2018, only the enumerated provisions of those 
documents apply to this appendix, as follows:

[[Page 36235]]

    0.1 ANSI Z21.47-2021
    (a) Sections 5.1, 5.1.4, 5.2, 5.3, 5.4, 5.5, 5.5.1, 5.6, and 
7.2.1 as specified in section 1.1 of this appendix;
    (b) Section 5.40 as specified in sections 1.1 and 3.1 of this 
appendix;
    (c) Section 5.2.8 as specified in section 4.1 of this appendix;
    (d) Annex I as specified in section 3.1 of this appendix.
    0.2 ASHRAE 103-2022
    (a) Sections 7.2.2.4, 7.8, and 9.2 as specified in section 2.2 
of this appendix;
    (b) Sections 11.3.7.1 and 11.3.7.2 as specified in section 4.1 
of this appendix.
    0.3 UL 727-2018
    (a) Sections 2, 3, 37, 38 and 39, 40, 40.6, 41, 42, 43.2, 44, 
45, and 46 as specified in section 1.2 of this appendix;
    (b) Figure 40.3 as specified in section 2.1 of this appendix.
    0.4 AHRI 1500-2015
    (a) Section C3.2.1.1 as specified in section 1.2 of this 
appendix;
    (b) Sections C7.2.4, C7.2.5, and C7.2.6.2 as specified in 
section 3.2 of this appendix.
    1. Test setup and Testing. Where this section prescribes use of 
ANSI Z21.47-2021 or UL 727-2018, perform only the procedures 
pertinent to the measurement of the steady-state efficiency, as 
specified in this section.
    1.1 Gas-fired commercial warm air furnaces. The test setup, 
including flue requirement, instrumentation, test conditions, and 
measurements for determining thermal efficiency are as specified in 
section 1.3 of this appendix, and the following sections of ANSI 
Z21.47-2021: 5.1 (General, including ASME PTC 19.3-1974 (R2004) as 
referenced in Section 5.1.4), 5.2 (Basic test arrangements), 5.3 
(Test ducts and plenums), 5.4 (Test gases), 5.5 (Test pressures and 
burner adjustments), 5.6 (Static pressure and air flow adjustments), 
5.40 (Thermal efficiency), and 7.2.1 (Basic test arrangements for 
direct vent central furnaces). If section 1.3 of this appendix and 
ANSI Z21.47-2021 have conflicting provisions (e.g., the number of 
thermocouples that should be used when testing units with flue 
outlets that have a cross-sectional area of 3.14 square inches or 
less), follow the provisions in section 1.3 of this appendix. The 
thermal efficiency test must be conducted only at the normal inlet 
test pressure, as specified in section 5.5.1 of ANSI Z21.47-2021, 
and at the maximum hourly Btu input rating specified by the 
manufacturer for the product being tested.
    1.2 Oil-fired commercial warm air furnaces. The test setup, 
including flue requirement, instrumentation, test conditions, and 
measurement for measuring thermal efficiency is as specified in 
section 1.3 of this appendix and the following sections of UL 727-
2018: 2 (Units of Measurement), 3 (Glossary, except that the 
definitions for ``combustible'' and ``non-combustible'' in sections 
3.11 and 3.27 shall be as referenced in NFPA 97-2003), 37 (General), 
38 and 39 (Test Installation), 40 (Instrumentation, except 40.4 and 
40.6.2 through 40.6.7 which are not required for the thermal 
efficiency test, and including ASTM E230/E230M-17 as referenced in 
Sections 40.6), 41 (Initial Test Conditions), 42 (Combustion Test--
Burner and Furnace), 43.2 (Operation Tests), 44 (Limit Control 
Cutout Test), 45 (Continuity of Operation Test), and 46 (Air Flow, 
Downflow or Horizontal Furnace Test). If section 1.3 of this 
appendix and UL 727-2018 have conflicting provisions (e.g., the 
number of thermocouples that should be used when testing units with 
flue outlets that have a cross-sectional area of 3.14 inches or 
less), follow the provisions in section 1.3 of this appendix. 
Conduct a fuel oil analysis for heating value, hydrogen content, 
carbon content, pounds per gallon, and American Petroleum Institute 
(API) gravity as specified in section C3.2.1.1 of AHRI 1500-2015, 
including the applicable provisions of ASTM D240-09, ASTM D4809-09a, 
ASTM D5291-10, and ASTM D396-14a, as referenced. The steady-state 
combustion conditions, specified in section 42.1 of UL 727-2018, are 
attained when variations of not more than 5 [deg]F in the measured 
flue gas temperature occur for three consecutive readings taken 15 
minutes apart.
    1.3 Additional test setup requirements for gas-fired and oil-
fired commercial warm air furnaces
    1.3.1 Thermocouple setup for gas-fired and oil-fired commercial 
warm air furnaces with flue outlets that have a cross-sectional area 
of 3.14 square inches or less. For units with flue outlets having a 
cross-sectional area of 3.14 square inches or less, the flue gas 
temperatures may optionally be measured using five individual 
thermocouples, instead of nine thermocouples.
    1.3.2 Procedure for flue gas measurements when testing units 
with multiple flue outlets. For units that have multiple flue 
outlets, record flue gas measurements (e.g., flue gas temperature, 
CO2 in the flue gasses) separately for each individual 
flue outlet and calculate a weighted-average value based on the 
readings of all flue outlets. To determine the weighted average for 
each measurement, first determine the input rating of the furnace 
module associated with each flue outlet. Then multiply the ratio of 
the input rating for the furnace module associated with each 
individual flue outlet to the total nameplate input rating of the 
furnace (i.e., the input rating associated with each individual flue 
outlet divided by the total nameplate input rating) by that flue 
outlet's respective component measurement and the sum of all of the 
products of the calculations for all of the flue outlets to 
determine the weighted-average values. Use the weighted-average 
values to determine flue loss, and whether equilibrium conditions 
are met before the official test period.
    2. Additional test measurements
    2.1 Determination of flue CO2 (carbon dioxide) or 
O2 (oxygen) for oil-fired commercial warm air furnaces. 
In addition to the flue temperature measurement specified in section 
40.6.8 of UL 727-2018, locate one or two sampling tubes within six 
inches downstream from the flue temperature probe (as indicated on 
Figure 40.3 of UL 727-2018). If an open end tube is used, it must 
project into the flue one-third of the chimney connector diameter. 
If other methods of sampling the flue gas are used, place the 
sampling tube so as to obtain an average sample. There must be no 
air leak between the temperature probe and the sampling tube 
location. Collect the flue gas sample at the same time the flue gas 
temperature is recorded. The CO2 or O2 
concentration of the flue gas must be as specified by the 
manufacturer for the product being tested, with a tolerance of 
0.1 percent. Determine the flue CO2 or 
O2 using an instrument with a reading error no greater 
than 0.1 percent.
    2.2 Procedure for the measurement of condensate for a gas-fired 
condensing commercial warm air furnace. The test procedure for the 
measurement of the condensate from the flue gas under steady-state 
operation must be conducted as specified in sections 7.2.2.4, 7.8, 
and 9.2 of ASHRAE 103-2022 under the maximum rated input conditions. 
This condensate measurement must be conducted for an additional 30 
minutes of steady-state operation after completion of the steady-
state thermal efficiency test specified in section 1.1 of this 
appendix.
    3. Calculation of thermal efficiency
    3.1 Gas-fired commercial warm air furnaces. Use the calculation 
procedure specified in Section 5.40, Thermal efficiency, of ANSI 
Z21.47-2021. When determining the flue loss that is used in the 
calculation of thermal efficiency, the calculation method specified 
in Annex I of ANSI Z21.47-2021 shall be used.
    3.2 Oil-fired commercial warm air furnaces. Calculate the 
percent flue loss (in percent of heat input rate) by following the 
procedure specified in sections C7.2.4, C7.2.5, and C7.2.6.2 of the 
AHRI 1500-2015. The thermal efficiency must be calculated as: 
Thermal Efficiency (percent) = 100 percent - flue loss (in percent).
    4. Procedure for the calculation of the additional heat gain and 
heat loss, and adjustment to the thermal efficiency, for a 
condensing commercial warm air furnace.
    4.1 Calculate the latent heat gain from the condensation of the 
water vapor in the flue gas, and calculate heat loss due to the flue 
condensate down the drain, as specified in sections 11.3.7.1 and 
11.3.7.2 of ASHRAE 103-2022, with the exception that in the equation 
for the heat loss due to hot condensate flowing down the drain in 
section 11.3.7.2, the assumed indoor temperature of 70 [deg]F and 
the temperature term TOA must be replaced by the measured 
room temperature as specified in section 5.2.8 of ANSI Z21.47.
    4.2 Adjustment to the thermal efficiency for condensing 
commercial warm air furnaces. Adjust the thermal efficiency as 
calculated in section 3.1 of this appendix by adding the latent 
gain, expressed in percent, from the condensation of the water vapor 
in the flue gas, and subtracting the heat loss (due to the flue 
condensate down the drain), also expressed in percent, both as 
calculated in section 4.1 of this appendix, to obtain the thermal 
efficiency of a condensing furnace.

0
6. Appendix B to subpart D of part 431 is added to read as follows:

[[Page 36236]]

Appendix B to Subpart D of Part 431-Uniform Test Method for Measurement 
of the Energy Efficiency of Commercial Warm Air Furnaces (Thermal 
Efficiency Two)

    Note:  Manufacturers must use the results of testing under this 
appendix B to determine compliance with any standards for commercial 
warm air furnaces that use the thermal efficiency 2 (TE2) metric. In 
addition, manufacturers may optionally make representations of 
energy use or efficiency of this equipment using TE2 as determined 
using this appendix starting on July 3, 2023.

    0. Incorporation by Reference.
    In Sec.  431.75, DOE incorporates by reference the entire 
standard ANSI Z21.47-2021. However, only section 5.40 and Appendix J 
of ANSI Z21.47-2021 apply, as specified in sections 1.2 and 1.6 of 
this appendix.
    1. Testing
    1.1 Set up and test the unit according to sections 0 through 4 
of appendix A to this subpart, while operating the unit at the 
maximum nameplate input rate (i.e., full load). Calculate thermal 
efficiency (TE) using the procedure specified in sections 3 and 4 of 
appendix A to this subpart.
    1.2 For commercial warm air furnaces that are designed for 
outdoor installation (including but not limited to CWAFs that are 
weatherized, or approved for resistance to wind, rain, or snow), or 
indoor installation within an unheated space (i.e., isolated 
combustion systems), determine the jacket loss using Section 5.40 
and Annex J of ANSI Z21.47-2021 while the unit is operating at the 
maximum nameplate input. The jacket shall consist of the surfaces 
surrounding the heating section of the furnace. The jacket includes 
all surfaces separating the heating section from the supply air, 
outside air, or condenser section, including the bottom surface 
separating the heating section from the basepan.
    1.3 For commercial warm air furnaces that are designed only for 
indoor installation within a heated space, jacket loss shall be 
zero. For commercial warm air furnaces that are designed for indoor 
installation within a heated or unheated space, multiply the jacket 
loss determined in section 1.2 of this appendix by 1.7. For all 
other commercial warm air furnaces, including commercial warm air 
furnaces that are designed for outdoor installation (including but 
not limited to CWAFs that are weatherized, or approved for 
resistance to wind, rain, or snow), multiply the jacket loss 
determined in section 1.2 of this appendix by 3.3.
    1.4 Subtract the jacket loss determined in section 1.3 of this 
appendix from the TE determined in section 1.1 of this appendix to 
determine the full-load efficiency.
    1.5 Set up and test the unit according to sections 0 through 4 
of appendix A to this subpart, while operating the unit at the 
nameplate minimum input rate (i.e., part load). Calculate TE using 
the procedure specified in sections 3 and 4 of appendix A to this 
subpart.
    1.6 For commercial warm air furnaces that are designed for 
outdoor installation (including but not limited to CWAFs that are 
weatherized, or approved for resistance to wind, rain, or snow), or 
indoor installation within an unheated space (i.e., isolated 
combustion systems), determine the jacket loss using Section 5.40 
and Annex J of ANSI Z21.47-2021 while the unit is operating at the 
minimum nameplate input. Alternatively, the jacket loss determined 
in section 1.2 of this appendix at the maximum nameplate input may 
be used.
    1.7 For commercial warm air furnaces that are designed only for 
indoor installation within a heated space, jacket loss shall be 
zero. For commercial warm air furnaces that are designed for indoor 
installation within a heated or unheated space, multiply the jacket 
loss determined in section 1.6 of this appendix by 1.7. For all 
other commercial warm air furnaces, including commercial warm air 
furnaces that are designed for outdoor installation (including but 
not limited to CWAFs that are weatherized, or approved for 
resistance to wind, rain, or snow), multiply the jacket loss 
determined in section 1.6 of this appendix by 3.3.
    1.8 Subtract the jacket loss determined in section 1.7 of this 
appendix from the TE determined in section 1.5 of this appendix to 
determine the part-load efficiency.
    1.9 Calculate TE2 by taking the average of the full-load and 
part-load efficiencies as determined in sections 1.4 and 1.8 of this 
appendix, respectively.

[FR Doc. 2023-11341 Filed 6-1-23; 8:45 am]
BILLING CODE 6450-01-P