[Federal Register Volume 80, Number 71 (Tuesday, April 14, 2015)]
[Proposed Rules]
[Pages 20116-20147]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-07932]



[[Page 20115]]

Vol. 80

Tuesday,

No. 71

April 14, 2015

Part III





Department of Energy





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10 CFR Parts 429, 430, and 431





Energy Conservation Program for Consumer Products and Certain 
Commercial and Industrial Equipment: Test Procedures for Consumer and 
Commercial Water Heaters; Proposed Rule

  Federal Register / Vol. 80 , No. 71 / Tuesday, April 14, 2015 / 
Proposed Rules  

[[Page 20116]]


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DEPARTMENT OF ENERGY

10 CFR Parts 429, 430, and 431

[EERE-2015-BT-TP-0007]
RIN 1904-AC91


Energy Conservation Program for Consumer Products and Certain 
Commercial and Industrial Equipment: Test Procedures for Consumer and 
Commercial Water Heaters

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

ACTION: Notice of proposed rulemaking.

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SUMMARY: As required by the Energy Policy and Conservation Act of 1975 
(EPCA), as amended, the U.S. Department of Energy (DOE) proposes to 
establish a mathematical conversion factor for the purpose of 
translating efficiency ratings for water heaters under the test method 
currently in effect to the ratings under the amended test method 
promulgated by DOE in a final rule published on July 11, 2014 
(hereinafter referred to as the ``the July 2014 final rule''). 
Compliance with the amended test procedure is required beginning on the 
later of: one year after the publication of a final rule that 
establishes a mathematical conversion factor, or December 31, 2015. 
This rulemaking document proposes a mathematical conversion factor 
which may be used to convert the existing efficiency ratings under the 
current Federal test procedure to efficiency ratings under the test 
procedure adopted in the July 2014 final rule for water heater basic 
models manufactured, tested and certified prior to the compliance date 
of the amended test procedure. The amended test procedure applies to 
all covered consumer water heaters and the covered commercial water 
heating equipment with residential applications defined in the July 
2014 final rule as a ``residential-duty commercial water heater.'' In 
addition, this document proposes amendments to the minimum energy 
conservation standards for consumer water heaters and residential-duty 
commercial water heaters to account for the impact of the new metric, 
but does not alter the stringency of the existing energy conservation 
standards. While DOE has not planned a public meeting to discuss this 
proposal, DOE is willing to consider a request to hold a meeting.

DATES: Comments: DOE will accept comments, data, and information 
regarding this notice of proposed rulemaking (NOPR) no later than May 
14, 2015. See section V, ``Public Participation,'' for details.

ADDRESSES: All comments submitted must identify the NOPR for the 
Conversion Factor for Test Procedures for Consumer and Certain 
Commercial Water Heaters, and provide docket number EERE-2015-BT-TP-
0007 and/or RIN 1904-AC91. Interested persons are encouraged to submit 
comments using the Federal eRulemaking Portal at www.regulations.gov. 
Follow the instructions for submitting comments. Alternatively, 
interested persons may submit comments by any of the following methods:
     Email: [email protected]. Include 
the docket number and/or RIN in the subject line of the message. Submit 
electronic comments in WordPerfect, Microsoft Word, PDF, or ASCII file 
format, and avoid the use of special characters or any form of 
encryption.
     Postal Mail: Ms. Brenda Edwards, U.S. Department of 
Energy, Building Technologies Office, Mailstop EE-5B, 1000 Independence 
Avenue SW., Washington, DC 20585-0121. If possible, please submit all 
items on a compact disc (CD), in which case it is not necessary to 
include printed copies.
     Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department 
of Energy, Building Technologies Office, 950 L'Enfant Plaza SW., 6th 
Floor, Washington, DC 20024. Telephone: (202) 586-2945. If possible, 
please submit all items on a CD, in which case it is not necessary to 
include printed copies.
    No telefacsimilies (faxes) will be accepted. For detailed 
instructions on submitting comments and additional information on the 
rulemaking process, see section V of this document (Public 
Participation).
    Docket: The docket is available for review at www.regulations.gov, 
including Federal Register notices, comments, and other supporting 
documents/materials. 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 information that is exempt 
from public disclosure.
    A link to the docket Web page can be found at: http://www.regulations.gov/#!docketDetail;D=EERE-2015-BT-TP-0007. This Web 
page contains a link to the docket for this notice of proposed 
rulemaking on the www.regulations.gov site. The www.regulations.gov Web 
page contains simple instructions on how to access all documents, 
including public comments, in the docket. See section V, ``Public 
Participation,'' for information on how to submit comments through 
www.regulations.gov.
    For information on how to submit a comment or review other public 
comments and the docket, contact Ms. Brenda Edwards at (202) 586-2945 
or by email: [email protected].

FOR FURTHER INFORMATION CONTACT: Ms. Ashley Armstrong, 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: (202) 586-6590. 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) 586-9507. Email: [email protected].

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Authority and Background
II. Summary of the Notice of Proposed Rulemaking
III. Discussion
    A. Stakeholder Comments on Other Rulemakings
    B. Scope
    1. Test Procedure and Energy Conservation Standards Coverage
    2. Units on the Market
    C. Potential Approaches for Developing Conversions
    1. Background Regarding Changes to Existing Test Procedures
    2. Analytical Methods
    3. Empirical Regression
    D. Testing Conducted for the Mathematical Conversion
    1. Consumer Water Heater Testing
    2. Residential-Duty Commercial Water Heater Testing
    E. Testing Results and Analysis of Test Data
    1. Impact of Certain Water Heater Attributes on Efficiency 
Ratings
    2. Conversion Factor Derivation
    3. Energy Conservation Standard Derivation
    F. Certification and Labeling Issues
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866
    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

[[Page 20117]]

    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
V. Public Participation
    A. Submission of Comments
    B. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

    Title III Part B \1\ of the Energy Policy and Conservation Act of 
1975 (``EPCA'' or, ``the Act''), Public Law 94-163 (42 U.S.C. 6291-
6309, as codified) sets forth a variety of provisions designed to 
improve energy efficiency and established the Energy Conservation 
Program for Consumer Products Other Than Automobiles.\2\ These include 
consumer water heaters, one subject of this document. (42 U.S.C. 
6292(a)(4)) Title III, Part C \3\ of EPCA, Public Law 94-163 (42 U.S.C. 
6311-6317, as codified), added by Public Law 95-619, Title IV, Sec. 
441(a), established the Energy Conservation Program for Certain 
Industrial Equipment, which includes the commercial water heating 
equipment that is another subject of this rulemaking. (42 U.S.C. 
6311(1)(K))
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    \1\ For editorial reasons, upon codification in the U.S. Code, 
Part B was redesignated Part A.
    \2\ All references to EPCA in this document refer to the statute 
as amended through the American Energy Manufacturing Technical 
Corrections Act (AEMTCA), Public Law 112-210 (Dec. 18, 2012).
    \3\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    Under EPCA, energy conservation programs generally consist of four 
parts: (1) Testing; (2) labeling; (3) establishing Federal energy 
conservation standards; and (4) certification and enforcement 
procedures. The testing requirements consist of test procedures that 
manufacturers of covered products and equipment must use as the basis 
for certifying to DOE that their products and equipment comply with the 
applicable energy conservation standards adopted under EPCA, and for 
making other representations about the efficiency of those products. 
(42 U.S.C. 6293(c); 42 U.S.C. 6295(s); 42 U.S.C. 6314) Similarly, DOE 
must use these test procedures to determine whether such products and 
equipment comply with any relevant standards promulgated under EPCA. 
(42 U.S.C. 6295(s))
    EPCA, as codified, contains what is known as an ``anti-
backsliding'' provision, which prevents the Secretary from prescribing 
any amended standard that either increases the maximum allowable energy 
use or decreases the minimum required energy efficiency of a covered 
product. (42 U.S.C. 6295(o)(1)) Also, the Secretary may not prescribe 
an amended or new standard if interested persons have established by a 
preponderance of the evidence that the standard is likely to result in 
the unavailability in the United States of any covered product type (or 
class) of performance characteristics (including reliability), 
features, sizes, capacities, and volumes that are substantially the 
same as those generally available in the United States. (42 U.S.C. 
6295(o)(4))
    EPCA prescribed energy conservation standards for consumer water 
heaters (42 U.S.C. 6295(e)(1)), and directed DOE to conduct further 
rulemakings to determine whether to amend these standards (42 U.S.C. 
6295(e)(4)(A)-(B)). DOE notes that under 42 U.S.C. 6295(m), the agency 
must periodically review its already established energy conservation 
standards for a covered product. Under this requirement, the next 
review that DOE would need to conduct must occur no later than six 
years from the issuance of a final rule establishing or amending a 
standard for a covered product.
    On April 16, 2010, DOE published a final rule (hereinafter referred 
to as the ``April 2010 final rule'') that amended the energy 
conservation standards for all classes of consumer water heaters, 
except for tabletop and electric instantaneous water heaters, for which 
the existing energy conservation standards were left in place. 75 FR 
20112. The standards adopted by the April 2010 final rule are shown 
below in Table I.1. These standards will apply to all water heater 
products listed in Table I.1 and manufactured in, or imported into, the 
United States on or after April 16, 2015, for all classes, except for 
tabletop and electric instantaneous. For these latter two classes, 
compliance with these standards has been required since April 15, 1991. 
55 FR 42162 (Oct. 17, 1990). Current energy conservation standards for 
consumer water heaters can be found in DOE's regulations at 10 CFR 
430.32(d).

                       Table I.1--Energy Conservation Standards for Consumer Water Heaters
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             Product class                 Rated storage volume ***                 Energy factor **
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Gas-fired Storage.....................  >=20 gal and <=55 gal........  0.675-(0.0015 x Vs)
                                        >55 gal and <=100 gal........  0.8012-(0.00078 x Vs)
Oil-fired Storage.....................  <=50 gal.....................  0.68-(0.0019 x Vs)
Electric Storage......................  >=20 gal and <=55 gal........  0.96-(0.0003 x Vs)
                                        >55 gal and <=120 gal........  2.057-(0.00113 x Vs)
Tabletop *............................  >=20 gal and <=120 gal.......  0.93-(0.00113 x Vs)
Gas-fired Instantaneous...............  <2 gal.......................  0.82-(0.0019 x Vs)
Electric Instantaneous *..............  <2 gal.......................  0.93-(0.00132 x Vs)
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*Tabletop and electric instantaneous standards were not updated by the April 2010 final rule.
** Vs is the ``Rated Storage Volume'' which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.
*** Rated Storage Volume limitations result from either a lack of test procedure coverage or from divisions
  created by DOE when adopting standards. The division at 55 gallons for gas-fired and electric storage water
  heaters was established in the April 16, 2010 final rule amending energy conservation standards. 75 FR 20112.
  The other storage volume limitations shown in this table are a result of test procedure applicability, and are
  discussed in the July 2014 final rule. 79 FR 40542 (July 11, 2014).

    The initial Federal energy conservation standards and test 
procedures for commercial water heating equipment were added to EPCA as 
an amendment made by the Energy Policy Act of 1992 (EPACT). (42 U.S.C. 
6313(a)(5)) These initial energy conservation standards corresponded to 
the efficiency levels contained in the American Society of Heating, 
Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1 
(ASHRAE Standard 90.1) in effect on October 24, 1992. The statute 
provided that if the efficiency levels in ASHRAE Standard 90.1 were 
amended after October 24, 1992, the Secretary must establish an amended 
uniform national standard at new minimum levels for each equipment type 
specified in ASHRAE Standard 90.1, unless DOE determines, through a 
rulemaking supported by clear and convincing evidence, that national 
standards more

[[Page 20118]]

stringent than the new minimum levels would result in significant 
additional energy savings and be technologically feasible and 
economically justified. (42 U.S.C. 6313(a)(6)(A)(ii)(I)-(II)) DOE 
issued the most recent final rule for commercial water heating 
equipment on January 12, 2001 (hereinafter, the ``January 2001 final 
rule''), which adopted the amended energy conservation standards at 
levels equivalent to efficiency levels in ASHRAE Standard 90.1, as it 
was revised in October 1999. 66 FR 3336. The current standards for 
commercial water heating equipment are presented in Table I.2 and may 
be found in DOE's regulations at 10 CFR 431.110.

                 Table I.2--Energy Conservation Standards for Commercial Water Heating Equipment
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                                                                    Energy conservation standard *
                                                    ------------------------------------------------------------
                                                         Minimum
           Equipment                    Size             thermal
                                                       efficiency              Maximum standby loss \c\
                                                           (%)
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Electric storage water heaters.  All...............             N/A  0.30 + 27/Vm (%/hr)
Gas-fired storage water heaters  <=155,000 Btu/hr..              80  Q/800 + 110(Vr) 1, 2 (Btu/hr)
                                 >155,000 Btu/hr...              80  Q/800 + 110(Vr) 1, 2 (Btu/hr)
Oil-fired storage water heaters  <=155,000 Btu/hr..              78  Q/800 + 110(Vr) 1, 2 (Btu/hr)
                                 >155,000 Btu/hr...              78  Q/800 + 110(Vr) 1, 2 (Btu/hr)
Gas-fired instantaneous water    <10 gal...........              80  N/A
 heaters and hot water supply
 boilers **.
                                 >=10 gal..........              80  Q/800 + 110(Vr) 1, 2 (Btu/hr)
Oil-fired instantaneous water    <10 gal...........              80  N/A
 heaters and hot water supply
 boilers **.
                                 >=10 gal..........              78  Q/800 + 110(Vr) 1, 2 (Btu/hr)
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           Equipment                    Size                          Minimum thermal insulation
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Unfired hot water storage tank.  All...............                             R-12.5
----------------------------------------------------------------------------------------------------------------
* Vm is the measured storage volume, and Vr is the rated volume, both in gallons. Q is the nameplate input rate
  in Btu/hr.
** For hot water supply boilers with a capacity of less than 10 gallons: (1) The standards are mandatory for
  products manufactured on and after October 21, 2005, and (2) products manufactured prior to that date, and on
  or after October 23, 2003, must meet either the standards listed in this table or the applicable standards in
  subpart E of this part for a ``commercial packaged boiler.''
*** Water heaters and hot water supply boilers having more than 140 gallons of storage capacity need not meet
  the standby loss requirement if: (1) The tank surface area is thermally insulated to R-12.5 or more; (2) a
  standing pilot light is not used; and (3) for gas or oil-fired storage water heaters, they have a fire damper
  or fan-assisted combustion.

    On December 18, 2012, the American Energy Manufacturing Technical 
Corrections Act (AEMTCA), Public Law 112-210, was signed into law. In 
relevant part, it amended EPCA to require that DOE publish a final rule 
establishing a uniform efficiency descriptor and accompanying test 
methods for covered consumer water heaters and commercial water heating 
equipment within one year of the enactment of AEMTCA. (42 U.S.C. 
6295(e)(5)(B)) The final rule must replace the current energy factor, 
thermal efficiency, and standby loss metrics with a uniform efficiency 
descriptor. (42 U.S.C. 6295(e)(5)(C)) The July 2014 final rule 
fulfilled these requirements. AEMTCA requires that, beginning one year 
after the date of publication of DOE's final rule establishing the 
uniform descriptor (i.e., July 13, 2015), the efficiency standards for 
the consumer water heaters and residential-duty commercial water 
heaters identified in the July 2014 final rule must be denominated 
according to the uniform efficiency descriptor established in that 
final rule (42 U.S.C. 6295(e)(5)(D)), and that DOE must develop a 
mathematical conversion factor for converting the measurement of 
efficiency for those water heaters from the test procedures and metrics 
currently in effect to the new uniform energy descriptor. (42 U.S.C. 
6295(e)(5)(E)(i)-(ii)) Consumer water heaters and residential-duty 
commercial water heaters manufactured prior to the effective date of 
the final rule (i.e., July 13, 2015) that comply with the efficiency 
standards and labeling requirements in effect prior to the final rule 
shall be considered to comply with the final rule and with any revised 
labeling requirements established by the Federal Trade Commission (FTC) 
to carry out the final rule. (42 U.S.C. 6295(e)(5)(K))
    AEMTCA also requires that the uniform efficiency descriptor and 
accompanying test method apply, to the maximum extent practicable, to 
all water-heating technologies currently in use and to future water-
heating technologies. (42 U.S.C. 6295(e)(5)(H)) AEMTCA allows DOE to 
provide an exclusion from the uniform efficiency descriptor for 
specific categories of otherwise covered water heaters that do not have 
residential uses, that can be clearly described, and that are 
effectively rated using the current thermal efficiency and standby loss 
descriptors. (42 U.S.C. 6295(e)(5)(F))
    AEMTCA outlines DOE's various options for establishing a new 
uniform efficiency descriptor for water heaters. The options that 
AEMTCA provides to DOE include: (1) A revised version of the energy 
factor descriptor currently in use; (2) the thermal efficiency and 
standby loss descriptors currently in use; (3) a revised version of the 
thermal efficiency and standby loss descriptors; (4) a hybrid of 
descriptors; or (5) a new approach. (42 U.S.C. 6295(e)(5)(G)) Lastly, 
AEMTCA requires that DOE invite stakeholders to participate in the 
rulemaking process, and that DOE contract with the National Institute 
of Standards and Technology (NIST), as necessary, to conduct testing 
and simulation of alternative descriptors identified for consideration. 
(42 U.S.C. 6295(e)(5)(I)-(J))
    As noted previously, in the July 2014 final rule, DOE amended its 
test procedure for consumer and certain commercial water heaters. 79 FR 
40542 (July 11, 2014). The July 2014 final rule for consumer and 
certain commercial water heaters satisfied the AEMTCA requirements to 
develop a uniform efficiency descriptor to replace the existing energy 
factor, thermal efficiency and standby loss metrics. The amended test 
procedure includes

[[Page 20119]]

provisions for determining the uniform energy factor (UEF), as well as 
the annual energy consumption of these products. Furthermore, the 
uniform descriptor test procedure can be applied to: (1) Most consumer 
water heaters (including certain consumer water heaters that are 
covered products under EPCA's definition of ``water heater'' at 42 
U.S.C. 6291(27), but that are not addressed by the existing test 
method); and (2) to commercial water heaters that have residential 
applications. The major modifications to the existing DOE test 
procedure to establish the uniform descriptor test method included the 
use of multiple draw patterns and different draw patterns, and changes 
to the set-point temperature. In addition, DOE expanded the scope of 
the test method to include test procedure provisions that are 
applicable to water heaters with storage volumes between 2 gallons (7.6 
L) and 20 gallons (76 L), and to clarify applicability to electric 
instantaneous water heaters. DOE also established a new equipment class 
and corresponding definition for ``residential-duty commercial water 
heater.''
    This rulemaking will satisfy the requirements of AEMTCA to develop 
a mathematical conversion factor for converting the measurement of 
efficiency for covered water heaters from the test procedures and 
metrics currently in effect to the new uniform energy descriptor. (42 
U.S.C. 6295(e)(5)(E))

II. Summary of the Notice of Proposed Rulemaking

    This notice of proposed rulemaking proposes to establish a 
mathematical conversion factor between the current rated values under 
the existing water heaters test procedures (i.e., energy factor, first-
hour rating, maximum gallons per minute (GPM) rating, thermal 
efficiency, standby loss), and the amended test procedure for the 
uniform efficiency descriptor (i.e., UEF and first-hour rating or 
maximum GPM rating), which was established in the July 2014 final rule. 
As discussed previously, the water heater test procedure was updated to 
be more representative of conditions encountered in the field 
(including modifications to both the test conditions and the draw 
patterns) and to expand the scope of the test procedure to apply to 
certain commercial and consumer water heaters that are currently not 
addressed by the test procedure.
    The mathematical conversion factor required by AEMTCA is a bridge 
between the efficiency ratings obtained through testing under the 
existing test procedures and those obtained under the uniform 
efficiency descriptor test procedure published in the July 2014 final 
rule. Therefore, the mathematical conversion factor will only apply to 
products and equipment covered by the existing test procedure, as 
products and equipment that are not covered by the existing test method 
would not have ratings to be converted. Certain water heater types are 
not covered by the mathematical conversion factor, either because they 
are not covered by the uniform efficiency descriptor established by the 
July 2014 final rule (e.g., commercial heat pump water heaters), or 
because they are not covered by DOE's existing test procedure (e.g., 
water heaters with storage volumes between 2 and 20 gallons). The water 
heater types that are and are not covered by the mathematical 
conversion factor are discussed in detail in section III.B of this 
notice of proposed rulemaking.
    To help develop the mathematical conversion factor, DOE conducted a 
series of tests on the types of water heaters included within the scope 
of this rulemaking (i.e., those described in section III.B and that 
pass the minimum standards for consumer \4\ and commercial water 
heaters). An investigation of DOE's Compliance Certification Management 
System (CCMS) and the Air-Conditioning, Heating, and Refrigeration 
Institute's (AHRI) water-heating databases found that certain types of 
water heaters are not available for purchase on the market; these units 
are discussed in section III.B. As there are no existing water heaters 
in these product classes, and the purpose of the conversion factor is 
to convert the efficiency ratings of existing water heaters, DOE did 
not include these water heaters in its analysis for the mathematical 
conversion factor.
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    \4\ DOE published a final rule on April 16, 2010, that will 
require compliance with amended energy conservation standards 
beginning on April 16, 2015. 75 FR 20112. DOE focused the testing of 
consumer water heaters on units that would comply with the amended 
standards.
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    DOE selected 72 water heaters for testing, including: 43 consumer 
storage units, 22 consumer instantaneous units, and 7 commercial 
residential-duty storage units. Units were selected to represent the 
range of rated values available on the market (i.e., storage volume, 
input rate, first-hour rating, maximum GPM, recovery efficiency, energy 
factor, thermal efficiency, and standby loss). DOE used data obtained 
from testing, along with analytical methods described in section III.C, 
to calculate the conversion factors described in this document. DOE 
investigated several approaches to derive these conversion factors, 
which are discussed in detail in section III.C of this notice of 
proposed rulemaking. DOE developed different conversion factors for 
determining first-hour rating, maximum GPM, and UEF based on the 
existing ratings for consumer and residential-duty commercial water 
heaters, which can be found in section III.E.
    DOE then used the conversion factors to derive minimum energy 
conservation standards based on the UEF, as shown in Table II.1 and 
Table II.2. The proposed standards based on UEF are neither more nor 
less stringent than the existing standards for consumer water heaters 
based on energy factor (as amended by the April 2010 final rule) and 
for commercial water-heating equipment based on the thermal efficiency 
and standby loss metrics. The methodology for deriving the proposed UEF 
standards is discussed in detail in section III.E.3 of this notice of 
proposed rulemaking.

                    Table II.1--Proposed Consumer Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                                  Rated storage
         Product class                volume              Draw pattern              Uniform energy factor *
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage.............  >=20 gal and <=55  Very Small...............  0.3263-(0.0019 x Vr)
                                 gal.
                                                   Low......................  0.5891-(0.0019 x Vr)
                                                   Medium...................  0.6326-(0.0013 x Vr)
                                                   High.....................  0.7128-(0.0025 x Vr)
                                >55 gal and <=100  Very Small...............  0.5352-(0.0007 x Vr)
                                 gal.
                                                   Low......................  0.7375-(0.0009 x Vr)
                                                   Medium...................  0.7704-(0.0010 x Vr)
                                                   High.....................  0.7980-(0.0010 x Vr)
Oil-fired Storage.............  <=50 gal.........  Very Small...............  0.2267-(0.0014 x Vr)

[[Page 20120]]

 
                                                   Low......................  0.4867-(0.0006 x Vr)
                                                   Medium...................  0.6016-(0.0012 x Vr)
                                                   High.....................  0.6529-(0.0005 x Vr)
Electric Storage..............  >=20 gal and <=55  Very Small...............  0.8268-(0.0002 x Vr)
                                 gal.
                                                   Low......................  0.9393-(0.0004 x Vr)
                                                   Medium...................  0.9683-(0.0007 x Vr)
                                                   High.....................  0.9656-(0.0004 x Vr)
                                >55 gal and <=120  Very Small...............  1.2701-(0.0011 x Vr)
                                 gal.
                                                   Low......................  1.9137-(0.0011 x Vr)
                                                   Medium...................  2.0626-(0.0011 x Vr)
                                                   High.....................  2.1858-(0.0011 x Vr)
Tabletop Storage..............  >=20 gal and       Very Small...............  0.6808-(0.0022 x Vr)
                                 <=100 gal.
                                                   Low......................  0.8770-(0.0012 x Vr)
                                                   Medium...................  0.9063-(0.0009 x Vr)
                                                   High.....................  0.9302-(0.0006 x Vr)
Gas-fired Instantaneous.......  <2 gal...........  All......................  0.8036-(0.0019 x Vr)
Electric Instantaneous........  <2 gal...........  All......................  0.9192-(0.0013 x Vr)
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.


           Table II.2--Proposed Residential-Duty Commercial Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
            Product class                        Draw pattern                     Uniform energy factor
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage....................  Very Small.....................  0.3261 - (0.0006 x Vr)
                                       Low............................  0.5219 - (0.0008 x Vr)
                                       Medium.........................  0.5585 - (0.0006 x Vr)
                                       High...........................  0.6044 - (0.0005 x Vr)
Oil-fired Storage....................  Very Small.....................  0.3206 - (0.0006 x Vr)
                                       Low............................  0.5577 - (0.0019 x Vr)
                                       Medium.........................  0.6027 - (0.0019 x Vr)
                                       High...........................  0.6446 - (0.0018 x Vr)
----------------------------------------------------------------------------------------------------------------
*Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.

    EPCA requires that a covered water heater be considered to comply 
with the July 2014 final rule on and after July 13, 2015 (the effective 
date of the July 2014 final rule) and with any revised labeling 
requirements established by the Federal Trade Commission to carry out 
the July 2014 final rule if the covered water heater was manufactured 
prior to July 13, 2015, and complied with the efficiency standards and 
labeling requirements in effect prior to July 13, 2015. (42 U.S.C. 
6295(e)(5)(K)) Upon the effective date of the final rule establishing 
the mathematical conversion factor (this rulemaking), compliance with 
energy conservation standards will be exclusively determined based on 
the standards as defined in terms of UEF, which will be established by 
this rulemaking. DOE has tentatively concluded that there will be three 
possible compliance paths available to manufacturers for basic models 
of consumer water heaters that were certified before July 13, 2015:
    (1) Convert the certified rating for energy factor obtained using 
the test procedure contained in Appendix E to subpart B of 10 CFR part 
430 of the January 1, 2015 edition of the CFR along with the applicable 
sampling provisions in 10 CFR part 429 from energy factor to uniform 
energy factor using the applicable mathematical conversion factor; or
    (2) Conduct testing using the test procedure contained at Appendix 
E to subpart B of 10 CFR part 430, effective July 13, 2015, along with 
the applicable sampling provisions in 10 CFR part 429; or
    (3) Where permitted, apply an alternative efficiency determination 
method (AEDM) pursuant to 10 CFR 429.70 to determine the represented 
efficiency of basic models for those categories of consumer water 
heaters where the ``tested basic model'' was tested using the test 
procedure contained at Appendix E to subpart B of 10 CFR part 430, 
effective July 13, 2015.
    Similarly, DOE has tentatively concluded that there will be three 
possible compliance paths available to manufacturers for basic models 
of commercial residential-duty water heaters that were certified before 
July 13, 2015:
    (1) Convert the certified rating for thermal efficiency and standby 
loss obtained using the test procedure contained in 10 CFR 431.106 of 
the January 1, 2015 edition of the CFR along with the applicable 
sampling provisions in part 429 from thermal efficiency and standby 
loss to uniform energy factor using the applicable mathematical 
conversion factor; or
    (2) Conduct testing using the test procedure at 10 CFR 431.106, 
effective July 13, 2015, along with the applicable sampling provisions 
in part 429; or
    (3) Where permitted, apply an alternative efficiency determination 
method (AEDM) pursuant to 10 CFR 429.70 to determine the represented 
efficiency of basic models for those categories of commercial water 
heaters where the ``tested basic model'' was tested using the test 
procedure at 10 CFR 431.106, effective July 13, 2015.
    After July 13, 2015, all new basic models (previously uncertified) 
must be rated using the new test procedure either by testing or by an 
AEDM, where allowed. All water heaters subject to the new test 
procedure adopted by the July 2014 final rule must be rated and 
certified in terms of UEF. DOE will assess compliance based upon the 
energy conservation standards expressed in terms of UEF as developed in 
this rulemaking. One year after the final rule in this rulemaking is 
published, all water heaters subject to the new UEF test procedure must 
be

[[Page 20121]]

rated and certified based on testing using the UEF test procedure or an 
AEDM, which is based on the UEF test procedure, where allowed. A 
summary of the options and requirements at various key dates is shown 
in the table below.

            Table II.3--Summary of Key Dates and Requirements
------------------------------------------------------------------------
     Description of date              Date              Requirements
------------------------------------------------------------------------
Test Procedure Effective      July 13, 2015.......  For new basic models
 Date.                                               introduced into
                                                     commerce on or
                                                     after July 13,
                                                     2015, manufacturers
                                                     must begin to test
                                                     and represent
                                                     efficiency using
                                                     the UEF metric
                                                     pursuant to the UEF
                                                     test procedure and
                                                     sampling plan (or
                                                     an AEDM that is
                                                     based on the UEF
                                                     test procedure,
                                                     where allowed).
Conversion Factor Effective   Date of publication   For basic models
 Date.                         of the conversion     certified using the
                               factor final rule     EF metric or
                               in the Federal        thermal efficiency
                               Register.             and/or standby loss
                                                     metrics prior to
                                                     July 13, 2015,
                                                     manufacturers must
                                                     transition all of
                                                     their
                                                     representations to
                                                     UEF either by
                                                     applying the
                                                     conversion
                                                     equations or by
                                                     using the UEF test
                                                     procedure and
                                                     sampling plan (or
                                                     an AEDM that is
                                                     based on the UEF
                                                     test procedure,
                                                     where allowed).
Conversion Factor Ending      One year after        All basic models
 Date.                         publication of        must be rated in
                               conversion factor     terms of UEF using
                               final rule.           the UEF test
                                                     procedure and
                                                     sampling plan or an
                                                     AEDM that is based
                                                     on the UEF test
                                                     procedure, where
                                                     allowed.
------------------------------------------------------------------------

III. Discussion

A. Stakeholder Comments on Other Rulemakings

    During the rulemaking process to develop the uniform efficiency 
descriptor test procedure, comments were received from stakeholders in 
reference to the derivation and applicability of the conversion factor. 
DOE deferred discussion of and response to those comments until such 
time as they could be addressed in this rulemaking.
    In response to the test procedure request for information (RFI \5\) 
published on January 11, 2013, DOE received seven written comments 
related to the conversion factor from the following interested parties: 
AHRI, A.O. Smith Corporation (A.O. Smith), Edison Electric Institute 
(EEI), Heat Transfer Products Inc. (HTP), the National Renewable Energy 
Laboratory (NREL), the Northwest Energy Efficiency Alliance (NEEA), and 
a joint comment on behalf of a number of environmental groups and 
efficiency advocates submitted by the American Council for an Energy-
Efficient Economy (ACEEE).\6\ These comments are discussed immediately 
below.
---------------------------------------------------------------------------

    \5\ 78 FR 2340.
    \6\ ACEEE submitted a joint comment on behalf of ACEEE, the 
Appliance Standards Awareness Project (ASAP), the Alliance to Save 
Energy (ASE), the National Consumer Law Center (NCLC), the National 
Resources Defense Council (NRDC), the Northwest Power and 
Conservation Council (NPCC), and the Northeast Energy Efficiency 
Partnerships (NEEP).
---------------------------------------------------------------------------

    NREL stated that there is not a simple conversion factor that will 
work across all systems, but suggested an application of the Water 
Heater Analysis Model (WHAM) \7\ to assist DOE in developing the 
conversion factor for storage water heaters. (NREL, EERE-2011-BT-TP-
0042-0029 at p. 4) The joint commenters supported the use of a ``good-
enough'' mathematical conversion method to express existing ratings in 
terms of the new uniform descriptor and urged DOE to test a sample of 
existing products to validate the algorithmic conversion method. (Joint 
comment, EERE-2011-BT-TP-0042-0035 at p. 4) HTP commented that the most 
exact approach would be to conduct an empirical analysis using curve 
fitting to actual test data, although the commenter acknowledged that 
there is not sufficient time for manufacturers to obtain this 
information and for the Department to then correlate and analyze the 
data. (HTP, EERE-2011-BT-TP-0042-0041 at p. 3)
---------------------------------------------------------------------------

    \7\ Lutz, Jim, Camilla D. Whitehead, Alex Lekov, David 
Winiarski, and Greg Rosenquist, WHAM: A Simplified Energy 
Consumption Equation for Water Heaters, Proc. of 1998 ACEEE Summer 
Study on Energy Efficiency in Buildings. Vol. 1. 171-83. Print.
---------------------------------------------------------------------------

    Regarding the derivation of updated energy conservation standards 
using the new uniform descriptor, AHRI and A.O. Smith commented that 
DOE should not simply test multiple units to determine an average 
difference between the current and new ratings and use that value to 
convert the ratings. (AHRI, EERE-2011-BT-TP-0042-0033 at p. 4; A.O. 
Smith, EERE-2011-BT-TP-0042-0034 at p. 3) NEEA commented that 
considering the limited laboratory capacity to test all water heaters 
under the revised method of test, DOE should assume that all water 
heaters that comply with current standards will also comply after the 
implementation of the new metrics. (NEEA, EERE-2011-BT-TP-0042-0037 at 
p. 6) EEI commented that the conversion factor should not make 
currently existing standards more stringent and should only be based on 
point-of-use metrics to be consistent with Federal law. (EEI, EERE-
2011-BT-TP-0042-0040 at p. 2)
    In response to the test procedure NOPR \8\ published on November 4, 
2013, DOE received three additional written comments related to the 
conversion factor from: AHRI, Bradford White Corporation (BWC) and a 
joint comment submitted on behalf of a number of environmental groups 
and efficiency advocates by ACEEE.\9\ AHRI and BWC suggested model 
types to test and urged DOE to release a schedule and process for the 
development of the conversion factor as soon as possible. (AHRI, EERE-
2011-BT-TP-0042-0075 at p. 6-7; BWC, EERE-2011-BT-TP-0042-0061 at p. 7) 
AHRI suggested two categories to be considered in the conversion factor 
rulemaking: water heater type and storage volume. BWC expanded on the 
list of categories supplied by AHRI by

[[Page 20122]]

including considerations for input capacity, venting options, tank 
configuration, NOX emissions, and mobile home certification. 
The joint comment suggested that the sensitivity of the energy factor 
to draw pattern be investigated and that systematic differences between 
``old'' and ``new'' values should be expected for several technologies. 
(Joint Comment, EERE-2011-BT-TP-0042-0077 at p. 2)
---------------------------------------------------------------------------

    \8\ 78 FR 66202.
    \9\ ACEEE submitted a joint comment on behalf of ACEEE, ASAP, 
ASE, Consumers Union (CU), NCLC, NRDC and NEEP.
---------------------------------------------------------------------------

    DOE has considered these comments fully in the development of this 
proposed rule. Although discussed in overview here, these comments are 
discussed in more detail later in this document as applicable to DOE's 
specific decisions regarding the mathematical conversion factor. In 
regards to the method of developing the conversion factor, DOE agrees 
in principle with the HTP comment that the most exact approach would be 
an empirical analysis using a curve-fitting method and actual test 
data, because such approach would account for all the changes made in 
the new test procedure, without having to make assumptions. However, 
DOE notes that the confidence in this empirical approach is dependent 
upon sample size and has considered whether the approach can feasibly 
be tested and implemented within the time constraints set forth by 
AEMTCA. (The curve-fitting method investigated is discussed in section 
III.C.3.)
    In addition, as suggested by NREL, DOE investigated the use of the 
WHAM model to predict water heater efficiency under the new test 
procedure parameters, and used the results in the conversion factor 
analysis. The methodology for applying WHAM and the results are found 
in section III.C.2.c. As suggested in the NOPR joint comment, the 
sensitivity of the UEF to draw pattern was investigated by including 
the drawn volume in the conversion factor calculations; this approach 
is discussed further in section III.C.
    In an effort to develop a mathematical conversion factor, DOE 
commissioned testing of 72 individual water heaters from various easily 
distinguishable water-heating categories under the updated test 
procedure. All of the water heaters chosen were found using either the 
Compliance Certification Management System (CCMS) or AHRI water heater 
databases, where the water heaters included in the databases were 
further distinguished based on the suggestions made by AHRI and BWC in 
response to the November 2013 water heaters NOPR (78 FR 66202 (Nov. 4, 
2013)). The models selected for testing and the parameters examined are 
described in more detail in section III.D. These test data were used to 
investigate all of the potential conversion factor methods described in 
section III.C.
    DOE has also carefully considered the comments regarding the 
establishment of energy conservation standards using the uniform 
efficiency descriptor metric (i.e., UEF). Those comments are discussed 
further in section III.E.3.

B. Scope

    The purpose of this section is to describe DOE's process for 
categorizing water heaters and establishing the range of units to be 
considered in this mathematical conversion factor rulemaking. DOE seeks 
comment on the scope of the conversion factor. This is identified as 
issue 1 in section V.E, ``Issues on Which DOE Seeks Comment.''
1. Test Procedure and Energy Conservation Standards Coverage
    To determine the appropriate scope of coverage for the mathematical 
conversion factor, DOE first considered the scope of its existing test 
procedures and energy conservation standards for consumer and 
commercial water heaters. Water heaters that are not currently subject 
to the DOE test procedures or standards were not included in the scope 
of the conversion factor, as they are not required to be tested and 
rated for efficiency under the DOE test method.
a. Consumer Water Heaters
    Under the existing regulatory definitions, DOE's current consumer 
water heater test procedures and energy conservation standards are not 
applicable to gas or electric water heaters with storage tanks that are 
at or above 2 gallons (7.6 L) and less than 20 gallons (76 L). In terms 
of the high end of the capacity range, the current DOE test procedure 
for consumer water heaters only applies to gas-fired water heaters with 
storage volumes less than or equal to 100 gallons (380 L), electric 
resistance and heat pump storage water heaters with storage volumes 
less than or equal to 120 gallons (450 L), and oil-fired water heaters 
with storage volumes less than or equal to 50 gallons (190 L). 10 CFR 
part 430, subpart B, appendix E, sections 1.12.1, 1.12.2, and 1.12.4.
    In the July 2014 final rule, DOE expanded the scope of the water 
heater test procedure for the uniform efficiency descriptor to include 
water heaters with storage volumes between 2 and 20 gallons and up to 
120 gallons. 79 FR 40542, 40547-48 (July 11, 2014).
    DOE's current consumer water heater test procedure and energy 
conservation standards are not applicable to gas-fired instantaneous 
water heaters with input capacities at or below 50,000 Btu/h or at or 
above 200,000 Btu/h. 10 CFR part 430, subpart B, appendix E, section 
1.7.2. In addition, the existing test procedure and energy conservation 
standards are not applicable to gas-fired storage water heaters with 
input capacities above 75,000 Btu/h, electric storage water heaters 
with input ratings above 12 kW, and oil-fired storage water heaters 
with input ratings above 105,000 Btu/h, as models exceeding those 
limits would not be classified as consumer water heaters under EPCA. 
(42 U.S.C. 6291(27)); 10 CFR part 430, subpart B, appendix E, sections 
1.12.1, 1.12.2, and 1.12.4.
    In the July 2014 final rule, DOE designed the test procedure so it 
is applicable to water heaters with any input capacity. Therefore, the 
lower limit for instantaneous water heaters no longer applies. 79 FR 
40542, 40548 (July 11, 2014).
    As discussed in the July 2014 final rule, definitions were added 
for ``electric instantaneous water heater,'' ``gas-fired heat pump 
water heater,'' and ``oil-fired instantaneous water heater,'' and the 
July 2014 test procedure is applicable to these types of appliances. 79 
FR 40542, 40549 (July 11, 2014).
    Although there is no definition for ``electric instantaneous water 
heater'' in the current test procedure in 10 CFR part 430, subpart B, 
Appendix E, an energy conservation standard exists for this type of 
water heater. In addition, the current test procedure can be applied to 
electric instantaneous water heaters, and manufacturers report energy 
factor ratings for these products. For these reasons, DOE has decided 
to include electric instantaneous water heaters with rated storage 
volumes <2 gallons and rated inputs <=12 kW in the conversion factor 
analysis.
    DOE has tentatively excluded the consumer water heater products 
listed in Table III.1 from consideration for the mathematical 
conversion factor due to the lack of an existing Federal test procedure 
and rating to be converted.

[[Page 20123]]



   Table III.1--Consumer Water Heaters Not Covered by the Mathematical
                            Conversion Factor
------------------------------------------------------------------------
                                           Description of criteria for
             Product class                  exclusion from conversion
                                                    rulemaking
------------------------------------------------------------------------
Gas-fired Storage......................  Rated Storage Volume >=2 gal
                                          and <20 gal or >100 gal and
                                          <=120 gal.
Oil-fired Storage......................  Rated Storage Volume >50 gal.
Electric Storage.......................  Rated Storage Volume >=2 gal
                                          and <20 gal.
Tabletop...............................  Rated Storage Volume >=2 gal
                                          and <20 gal.
Gas-fired Instantaneous................  Rated Input <= 50,000 Btu/h;
                                          Rated Storage Volume >2 gal.
Electric Instantaneous.................  Rated Storage Volume >2 gal.
------------------------------------------------------------------------

b. Commercial Water Heaters
    As stated in the July 2014 final rule, DOE excluded from the 
uniform efficiency descriptor any specific category of water heater 
that does not have a residential use, can be clearly described, and can 
be effectively rated using the current thermal efficiency and standby 
loss descriptors. 79 FR 40542, 40545 (July 11, 2014). DOE determined 
that certain commercial water heaters met these criteria to be excluded 
from the uniform efficiency descriptor, and distinguished them from 
water heaters that do not meet the criteria by establishing equipment 
classes for residential-duty commercial water heaters. Commercial water 
heaters meeting the definition of ``residential-duty commercial water 
heater'' do not meet the criteria for exclusion, and thus, are included 
in the uniform efficiency descriptor while all other commercial water 
heaters are not. DOE determined that three criteria would be used to 
distinguish residential-duty commercial water heaters from other 
commercial water heaters (79 FR 40542, 40547 (July 11, 2014)):
    (1) For models requiring electricity, uses single-phase external 
power supply;
    (2) Is not designed to provide outlet hot water at temperatures 
greater than 180[emsp14][deg]F; and
    (3) Is not excluded by the limitations regarding rated input and 
storage volume presented in Table III.2.

 Table III.2--Capacity Limitations for Defining Commercial Water Heaters
      Without Residential Applications (i.e., Non-Residential-Duty)
------------------------------------------------------------------------
                                           Indicator of non-residential
           Water heater type                       application
------------------------------------------------------------------------
Gas-fired Storage......................  Rated input >105 kBtu/h; Rated
                                          storage volume >120 gallons.
Oil-fired Storage......................  Rated input >140 kBtu/h; Rated
                                          storage volume >120 gallons.
Electric Storage.......................  Rated input >12 kW; Rated
                                          storage volume >120 gallons.
Heat Pump with Storage.................  Rated input >15 kW; Rated
                                          current >24 A at a rated
                                          voltage of not greater than
                                          250 V; Rated storage volume
                                          >120 gallons.
Gas-fired Instantaneous................  Rated input >200 kBtu/h; Rated
                                          storage volume >2 gallons.
Electric Instantaneous.................  Rated input >58.6 kW; Rated
                                          storage volume >2 gallons.
Oil-fired Instantaneous................  Rated input >210 kBtu/h; Rated
                                          storage volume >2 gallons.
------------------------------------------------------------------------

    DOE did not include commercial water-heating equipment that does 
not meet the definition of a ``residential-duty commercial water 
heater'' in its consideration of the mathematical conversion factor, as 
the equipment is not subject to the uniform efficiency descriptor test 
procedure. Additionally, DOE notes that there are no electric storage 
water heaters that would be considered to be residential-duty 
commercial since the qualifications shown in Table II.2 would place an 
electric storage water heater in the consumer category. Since there are 
no such units, and could not be such units under the applicable 
definition, a conversion is unnecessary. DOE is, therefore, not 
proposing a conversion factor for residential-duty electric storage 
water heaters. DOE also notes that a water heater that meets the 
definition of a consumer electric storage water heater must be tested 
and rated as a consumer electric storage water heater even if it is 
marketed as part of a commercial product line.
    As stated in the July 2014 final rule, DOE has determined that 
certain commercial equipment including unfired storage tanks, add-on 
heat pump water heaters, and hot water supply boilers are not 
appropriately rated using the uniform descriptor applicable to other 
water heaters, and, thus, will continue to be rated using the existing 
metrics. 79 FR 40542, 40547.
    Electric instantaneous water heaters are currently subject to the 
commercial water heating equipment test procedures but do not have an 
associated energy conservation standard. 10 CFR 431.106; 10 CFR 
431.110. Because there is no commercial energy conservation standard 
for electric instantaneous water heaters, a conversion to the UEF 
cannot be made.
2. Units on the Market
    As stated in section II, DOE undertook an investigation into the 
water-heating units on the market at the time of the publication of the 
final rule establishing the UEF test procedure. The AHRI commercial 
water heater database along with the CCMS consumer water heater 
database were examined to select representative units for testing and 
analysis.
    DOE's analysis focused on the models that meet the energy 
conservation standards contained in the April 2010 final rule, which 
will require compliance on April 16, 2015. The storage volume divisions 
at 55 gallons in the gas-fired and electric storage product classes, as 
established in the April 16, 2010 final rule, represent a divide in 
technology. For gas-fired storage units above 55 gallons manufactured 
on and after April 16, 2015, the energy conservation standard will be 
high enough that current designs can only achieve the required 
efficiency through the use of condensing technology.\10\ For electric 
storage units with storage volumes above 55 gallons, only heat pump 
water heaters currently

[[Page 20124]]

have the ability to reach the April 16, 2015 energy conservation 
standard levels. While the UEF test procedure will apply to both 
electric and gas units in this range, DOE found that for gas-fired 
storage water heaters, there are currently no consumer water heaters 
above 55 gallons that would be compliant with the updated standard, so 
no units were tested for development of a conversion factor. For 
electric storage water heaters, heat pump water heaters meet or exceed 
the amended energy conservation standards and, thus, were candidates 
for inclusion in the test plan for the conversion factor. There are no 
oil-fired instantaneous or oil-fired storage water heaters above 50 
gallons available on the market.
---------------------------------------------------------------------------

    \10\ In a condensing water heater, the combustion gases are 
cooled such that the temperature is reduced below the dew point and 
condensation occurs, allowing the latent heat of vaporization to be 
captured and improving the efficiency of the heat exchange between 
the combustion gases and the water.
---------------------------------------------------------------------------

    In reviewing the commercial water heating market, DOE found that 
commercial oil-fired instantaneous water heaters are available on the 
market but do not meet the definition of ``residential-duty commercial 
water heater,'' as they have storage volumes greater than 2 gallons. 
DOE found that all commercial gas-fired instantaneous units exceeded 
the maximum delivery temperature of 180 [deg]F for residential-duty 
commercial water heaters, and, thus, would be regulated using the 
existing thermal efficiency and standby loss metrics. DOE also found 
that commercial electric instantaneous units which meet the definition 
of ``residential-duty commercial water heater'' exist, however, as 
stated in section III.B.1.b, no energy conservation standard exists for 
these units; therefore a conversion factor was not developed.
    Consequently, none of the commercial water heaters identified above 
could be tested or examined for use in this rulemaking. In addition, a 
conversion factor for these water heaters is not needed because there 
are no units in existence with efficiency ratings that can be 
converted. However, because a manufacturer may want to design and 
produce products in these equipment classes in the future, DOE must 
establish energy conservation standards in terms of the UEF metric. 
Accordingly, DOE used information gained from other product classes to 
establish these energy conservation standards, as discussed in section 
III.E.

C. Potential Approaches for Developing Conversions

1. Background Regarding Changes to Existing Test Procedures
a. Consumer Water Heater Test Procedures
    Both the current test procedure and the uniform efficiency 
descriptor test procedure consist of a delivery capacity test and a 24-
hour simulated-use test. The delivery capacity tests for storage and 
instantaneous water heaters are the first-hour rating and maximum GPM 
tests, respectively. These tests are largely unchanged from the current 
to the new test procedure, except for modifications to account for the 
decrease in delivered water temperature from a nominal value of 135 
[deg]F to 125 [deg]F. The results of those tests, however, have 
implications on the 24-hour simulated-use test under the new test 
procedure that are absent under the current test procedure.
    In the current test procedure, the delivery capacity has no effect 
on the 24-hour simulated-use test, which consists of six hot water 
draws, of equivalent volumes, at the start of the test and each of the 
first five subsequent hours. The water heater is then in standby mode 
for the remainder of the test. In the July 2014 final rule, however, 
the delivery capacity determines the draw pattern for the 24-hour 
simulated-use test. According to the new test procedure, a water 
heater's delivery capacity can be categorized as either very small, 
low, medium, or high; these usages are shown below in Table III.3. 79 
FR 40542, 40572 (July 11, 2014). These usage categories have an 
associated draw pattern prescribed to them during the 24-hour 
simulated-use. Depending on the delivery capacity associated with a 
water heater, between 9 and 14 hot water draws of various volumes and 
flow rates are required.

                             Table III.3--Delivery Capacity Categorization Criteria
----------------------------------------------------------------------------------------------------------------
                                    First-Hour Rating, gal               Maximum GPM, gpm
         Draw Pattern         ------------------------------------------------------------------- Drawn  Volume,
                                     >=                <               >=               <               gal
----------------------------------------------------------------------------------------------------------------
Very Small...................               0  18..............            0    1.7.............              10
Low..........................              18  51..............            1.7  2.8.............              38
Medium.......................              51  75..............            2.8  4...............              55
High.........................              75  No upper limit..            4    No upper limit..              84
----------------------------------------------------------------------------------------------------------------

    In the existing DOE consumer water heater test procedure, a 
temperature of 135 [deg]F  5 [deg]F is used for the set-
point temperature for storage water heaters (measured as the mean tank 
temperature) and the delivery temperature for instantaneous water 
heaters. In the uniform efficiency descriptor test procedure set forth 
in the July 2014 final rule, a temperature of 125 [deg]F  5 
[deg]F is used for the set-point temperature for storage water heaters 
(measured as the delivery temperature) and the delivery temperature of 
instantaneous water heaters. 79 FR 40542, 40554 (July 11, 2014).
b. Commercial Water Heater Test Procedure
    The current test procedure for rating commercial water heaters 
consists of a steady-state test to determine thermal efficiency and a 
test lasting between 24 and 48 hours to measure the standby loss. 77 FR 
28996 (May 16, 2012); 10 CFR 431.106. For electric resistance water 
heaters, the thermal efficiency is assigned a value of 98 percent in 
lieu of testing. The set-point temperature of the water heater is 140 
[deg]F  5 [deg]F, and the unit sits in an environment with 
an ambient temperature of 75 [deg]F  10 [deg]F. Water is 
supplied to the water heater at a temperature of 70 [deg]F  
2 [deg]F. Instantaneous water heaters are not required to undergo a 
standby loss test.
    Under the uniform efficiency descriptor test procedure, commercial 
water heaters falling under the ``residential-duty'' category will now 
be subject to the first-hour rating or maximum GPM test and simulated-
use tests specified in the previous section (III.C.1.a), with the same 
set-point temperature, ambient temperature, and inlet water temperature 
as is applied to consumer water heaters.
2. Analytical Methods
    For converting existing ratings to ratings under the uniform 
efficiency descriptor test method, DOE considered equations based on a 
water heater's physical characteristics; these approaches will be 
termed analytical methods. The sections below describe

[[Page 20125]]

potential analytical methods for the three key metrics that result from 
the uniform efficiency descriptor test method: (1) The maximum GPM; (2) 
the first-hour rating; and (3) the UEF. In the discussion immediately 
below, DOE introduces key factors that it expects will change ratings 
from the existing consumer and commercial water heater test procedures 
to the new uniform efficiency descriptor test procedure.
a. Maximum GPM
    For flow-activated water heaters, the delivery capacity is 
determined by the 10-minute maximum GPM rating test. During this test, 
the water heater runs at maximum firing rate to raise the temperature 
from its nominal value of 58 [deg]F to the prescribed delivery 
temperature. This flow rate is determined by the following equation:
[GRAPHIC] [TIFF OMITTED] TP14AP15.006

where VV is the volumetric flow rate of water, Q is the firing rate, 
[eta]r is the recovery efficiency, [rho] is the density of 
the delivered water, cp is the specific heat of the 
delivered water, Tdel is the delivered water temperature, 
and Tin is the inlet water temperature. If it is assumed 
that the firing rate and recovery efficiency are the same with water 
delivered at 125 [deg]F and 135 [deg]F, then the ratio of the maximum 
GPM at 125 [deg]F versus that at 135 [deg]F is determined by the 
following equation:
[GRAPHIC] [TIFF OMITTED] TP14AP15.007

    Therefore, an analytical conversion from the existing maximum GPM 
rating (VVex) for consumer water heaters to the rating under the test 
conditions in the uniform efficiency descriptor test method (VVUED) is:

VVUED = 1.147VVex

    As discussed in detail in section III.E.2, tests on flow-activated 
water heaters showed a change in maximum GPM rating under the uniform 
efficiency descriptor test method that correlated well with the above 
equation.
b. First-Hour Rating
    For water heaters that have a heat source controlled by means other 
than sensing flow (e.g., thermostatically-controlled), the delivery 
capacity is determined through a first-hour rating test. During this 
test, the water heater begins in its fully heated state, and water is 
drawn from it at a specified flow rate until the temperature of the 
delivered water drops a specified amount. The water heater is then 
allowed to recover, and subsequent draws are initiated when the 
controller acts to reduce the heat input to particular burners or 
heating elements specified in the test procedure. These subsequent 
draws are terminated based on the same criterion that is used for the 
first draw, namely that the outlet water temperature drops a set amount 
of degrees from its maximum value during that draw. When the test 
reaches a duration of one hour from the start of the first draw, the 
test concludes after the draw termination criterion is reached for the 
draw taking place at one hour from the start of the test. If no draw is 
occurring at the one hour duration, a draw is initiated and terminated 
when the outlet water temperature reaches the termination temperature 
of the previous draw, and the test is concluded upon termination of 
that draw.
    In the uniform efficiency descriptor test procedure, the primary 
change that will affect the first-hour rating is the shift from a 
nominal delivery temperature of 135 [deg]F to 125 [deg]F and the 
accompanying adjustment to the draw termination criterion to a decrease 
in delivered water temperature from 25 [deg]F in the current consumer 
water heater test method to 15 [deg]F in the uniform efficiency 
descriptor test method. Because the initial set-point temperature is 
reduced in the uniform efficiency descriptor as compared to the 
existing consumer water heater test procedure, less stored thermal 
energy will be available at the start of the test. However, this effect 
is countered because the lower set-point temperature allows the water 
heater to recover quicker (as the water only needs to be heated to a 15 
[deg]F temperature rise rather than a 25 [deg]F temperature rise), 
thereby allowing subsequent draws to start sooner than they would under 
the current test procedure. Thus, due to these offsetting effects, DOE 
has observed through testing that sometimes the first-hour rating is 
increased when tested under the uniform efficiency descriptor, and 
sometimes the rating is decreased. DOE is not aware of any analytical 
models that would mathematically represent this behavior, so it has 
chosen not to pursue such an approach for converting existing first-
hour ratings to first-hour ratings under the uniform efficiency 
descriptor. Rather, as discussed in section III.C.3, DOE chose an 
approach based on an empirical regression for converting the first-hour 
ratings.
    Likewise, DOE is not aware of any analytical method that will 
convert rated values of thermal efficiency and standby loss for 
residential-duty commercial storage water heaters to a first-hour 
rating. Therefore, DOE chose an approach based on empirical regression 
for converting existing ratings of residential-duty commercial water 
heaters to first-hour ratings.
c. Uniform Energy Factor
    A number of changes to the 24-hour simulated-use test will alter 
the water heater energy efficiency ratings from the existing water 
heater test procedures as compared to the ratings obtained under the 
uniform efficiency descriptor test method. Among the key changes that 
are expected to alter the efficiency metric for consumer water heaters 
are: (1) A different volume of water withdrawn per test; (2) a change 
in the draw pattern (i.e., number of draws, flow rates during draws, 
timing of draws) applied during the test; (3) reduction of the test 
temperature from an average stored temperature of 135 [deg]F to a 
delivered water temperature of 125 [deg]F; and (4) removal of the 
stipulation to normalize the energy consumption to maintain a 
prescribed average water temperature within the storage tank. 
Residential-duty commercial water heaters will see a change from the 
thermal efficiency and standby loss metrics currently in place to the 
UEF, which consists of an entirely new approach for rating efficiency.
i. Consumer Storage Water Heaters
    A simple theoretical model for determining the energy consumption 
of a storage-type water heater based on key test parameters, termed the 
Water Heater Analysis Model (WHAM), was

[[Page 20126]]

presented by Lutz et al.\11\ The equation for the energy input (Q) over 
a 24-hour period is determined using the following equation:
---------------------------------------------------------------------------

    \11\ Lutz, Jim, Camilla Dunham Whitehead, Alex Lekov, David 
Winiarski, and Greg Rosenquist. ``WHAM: A Simplified Energy 
Consumption Equation for Water Heaters'' In Proceedings of the 1998 
ACEEE Summer Study on Energy Efficiency in Buildings (1998) 
(Available at: http://cgec.ucdavis.edu/ACEEE/1998/pdffiles/papers/0114.pdf) (Last accessed October 1, 2014).
[GRAPHIC] [TIFF OMITTED] TP14AP15.008

where [rho] is the density of water, cp is the specific heat 
of water, [eta]r is the recovery efficiency, V is the volume 
of water delivered per day, UA is the heat loss factor, 
Ttank is the average temperature of the water stored within 
the tank of a storage water heater, P is the input power to the water 
heater in Btu/h, Tamb is the average ambient temperature 
during the test, and 24 is the number of hours in the test. This 
equation considers the energy required to heat the water that is 
delivered by the water heater from the inlet water temperature up to 
the delivery temperature and the energy required to make up the heat 
lost from the water heater to the surrounding environment. The time 
over which this standby energy loss is determined is corrected by the 
term with the power in the denominator to account for the fact that 
[eta]r, as calculated in the test, accounts for standby 
energy loss during periods when heat input to the water is activated.
    This calculated energy can then be used to estimate the daily 
efficiency, Eff, under a given daily water demand (e.g., that required 
during the current EF test or that required during the UEF test):
[GRAPHIC] [TIFF OMITTED] TP14AP15.009

    Currently, directories of water heater ratings provide the Eff 
(i.e., Energy Factor), P, and [eta]r. Since the EF testing 
entails a prescribed Tdel (135 [deg]F), Tin (58 
[deg]F), Ttank (135 [deg]F), Tamb (67.5 [deg]F), 
and V (64.3 gallons), the two equations can be solved for the two 
remaining unknowns, Q and UA. The exception to this approach is heat 
pump water heaters. For these units, the reported recovery efficiency 
([eta]r) is that of the resistance element inside the water 
heater. Since it is expected that the heat pump unit would provide the 
majority of the heating during the simulated-use test as opposed to the 
resistance element, the required data to use the WHAM model for heat 
pump water heaters is not readily available in publicly accessible 
directories. For these units, DOE proposes to base the conversion 
equation purely on experimental data.
    After the equations are solved to determine UA, if one assumes that 
the UA and [eta]r do not change under the new test approach, 
then the two equations can be solved again (this time inserting the UA 
value obtained from solving the previous set of equations) to determine 
the values for Q and Eff (i.e., UEF) under the uniform efficiency 
descriptor test method using the prescribed values for the uniform 
efficiency descriptor test procedure of Tdel (125 [deg]F), 
Tin (58 [deg]F), Ttank (125 [deg]F), 
Tamb (67.5 [deg]F), and V (varies depending upon draw 
pattern).
    This formulation entails a number of assumptions. A major 
assumption is that the average tank temperature is approximately equal 
to the delivered water temperature. As previously noted, the new 
procedure does not normalize the average stored water temperature to a 
prescribed value, so this estimate may not be completely accurate. Some 
water heaters have demonstrated that average tank temperature is below 
the typical delivered temperature because of stratification. This 
effect is believed to be most pronounced with condensing water heaters. 
Other water heaters show some stratification, but the average water 
temperature within the tank is typically closer to the delivered water 
temperature. Another assumption in this formulation is that the 
recovery efficiency and UA values do not change when the water heater 
stores water for delivery at 135 [deg]F compared to storing it at 125 
[deg]F. While electric resistance water heaters have a prescribed 
recovery efficiency of 98 percent, other technologies may see changes 
in the recovery efficiency as the temperature drops. For example, the 
study by Sparn et al. shows plots of the Coefficient of Performance 
(COP), which is one aspect of the recovery efficiency, for heat pump 
water heaters.\12\ Their data suggest an increase in COP of 
approximately 15 percent with the average tank temperature at 125 
[deg]F compared to 135 [deg]F. Data obtained by DOE indicate an 
increase in recovery efficiency obtained during the same draw profile 
of between 3 and 13 percent, with an average of 8 percent. Data 
collected on fossil-fuel-fired water heaters show negligible dependency 
of the recovery efficiency on the prescribed tank temperature. The UA 
value may change slightly based on higher heat transfer coefficients at 
higher temperatures or changes in the thermal conductivity of 
insulating materials at higher temperatures. Data collected by DOE 
suggest that the UA value decreases 7 percent from 135 [deg]F to 125 
[deg]F.
---------------------------------------------------------------------------

    \12\ Sparn, B., K. Hudon, and D. Christensen, Laboratory 
Performance Evaluation of Residential Integrated Heat Pump Water 
Heaters. National Renewable Energy Laboratory (September 2011) 
(Available at: http://www.nrel.gov/docs/fy11osti/52635.pdf) (Last 
accessed October 1, 2014).
---------------------------------------------------------------------------

    For an initial estimate, DOE considered the situation where the UA 
and recovery efficiency do not change with temperature. The equations 
above can estimate the effects of two key factors that have changed in 
the test procedure, namely the volume drawn per day and the delivery 
temperature. As more water is delivered, the fraction of energy 
required to make up the standby losses compared to the overall energy 
required by the water heater is diminished, thereby increasing the 
fraction of energy going towards hot delivered water and increasing the 
efficiency. The change in set-point temperature appears to have less of 
an effect on water heater efficiency, since two competing factors are 
at play. With a lower stored water temperature, the standby losses are 
decreased, thereby increasing the overall efficiency of the water 
heater. The lower delivery temperature, however, means that less energy 
is delivered per gallon, so the energy delivered for a given volume 
delivered per day is less than that when the water is delivered at 135 
[deg]F, thereby decreasing the efficiency of the water heater.
    As noted, direct use of this model may not properly account for 
changes to the recovery efficiency, UA value, or normalization 
procedure for standby heat loss. Therefore, DOE has chosen a two-step 
process to convert the existing Energy Factor ratings for consumer 
storage water heaters to the UEF. First, using the equations and 
assumptions described above, a prediction of the

[[Page 20127]]

efficiency given by WHAM is determined, termed UEFWHAM. This value is 
then considered as part of a regression analysis (see section III.C.3) 
to obtain a relationship that will convert from EF to UEF. DOE believes 
that the use of WHAM will capture the primary effects of changes in the 
volume of water delivered per day along with changes in the set-point 
temperature. Regression with experimental data will then capture the 
effects that may not be fully accounted for by WHAM, such as 
differences in the UA value, recovery efficiency, and the change to the 
normalization calculation procedure for standby heat loss.
    To establish a clear method of applying the analytical model, the 
WHAM-based UEF equation and Table III.4, comprising the coefficients 
based on draw bin, are presented below. This equation incorporates the 
equations and assumptions presented above, where [eta]r and 
EF are the recovery efficiency and energy factor, respectively, based 
on the current DOE test procedure, and P is the nameplate input rate in 
Btu/h. As shown in Table III.4, constants ``a,'' ``b,'' ``c,'' and 
``d'' are dependent on the volume of water being drawn.
[GRAPHIC] [TIFF OMITTED] TP14AP15.010


                         Table III.4--Coefficients for WHAM-based UEF Conversion Factor
----------------------------------------------------------------------------------------------------------------
                    Draw bin                             a               b               c               d
----------------------------------------------------------------------------------------------------------------
Very Small......................................        56095146     12884892499         8930623     15125743368
Low.............................................        56095146     48962591496        33936368     57477824799
Medium..........................................        56095146     70866908744        49118427     83191588525
High............................................        56095146    108233096990        75017235    127056244293
----------------------------------------------------------------------------------------------------------------

ii. Consumer Instantaneous Water Heaters
    WHAM is not directly applicable to instantaneous water heaters 
because it assumes that the water heater loses heat at a constant rate 
throughout the day when the heating element is not energized. For 
instantaneous water heaters, this modeling approach is inappropriate 
since the unit does not store water at an elevated temperature 
throughout the day, rather heating water as it flows through the unit.
    Instantaneous water heaters instead experience a separate type of 
heat loss to the surroundings that sometimes result in Energy Factors 
that are below the steady-state thermal efficiency. This loss occurs 
when heat that is present in the water heater at the end of a draw 
dissipates to the ambient. If a draw is not initiated shortly after the 
end of a draw, then most of this heat is lost. If, however, a 
subsequent draw starts shortly after a previous draw, some of that heat 
is captured in the hot water that is delivered.
    DOE attempted to capture these effects in a modified equation that 
separately accounts for energy consumption that goes towards supplying 
heat to the delivered water and energy consumption that goes towards 
heating up the materials making up the water heater:
[GRAPHIC] [TIFF OMITTED] TP14AP15.011

where LF is a loss factor related to the amount of energy stored in the 
materials of the water heater and N* is the number of draws from which 
heat loss occurs to the environment. LF is approximately equal to the 
mass of the material within the water heater times its heat capacity. 
N* is not simply the number of draws during the day, since some draws 
may occur close together and do not result in total energy loss. To 
determine the fraction of energy from a draw that is lost, DOE examined 
data from testing that suggested that most heat is lost from tankless 
water heaters after about one hour. Using this value, DOE scaled the 
energy loss for a draw by the length of the standby time following the 
draw. For example, a draw followed by over one hour of standby time 
would contribute a value of 1 to N* for that test. A draw followed by 
30 minutes of standby time prior to the next draw would contribute a 
value of (30 min)/(60 min) = 0.5 to N*. Contributions from each draw in 
a test pattern are added to obtain a value for N* for each draw 
pattern. For the existing DOE consumer water heater test, N* is 5.64, 
as the standby time following each draw is slightly under 60 minutes. 
The values for N* for all draw patterns are provided in Table III.5.

   Table III.5--Estimate of Number of Draws From Which All Energy From
                  Water Heater Is Lost to Surroundings
------------------------------------------------------------------------
                          Draw pattern                              N*
------------------------------------------------------------------------
Existing Consumer Water Heater Draw Pattern....................     5.64
Very-Small-Use.................................................     4.36
Low-Use........................................................     6.72
Medium-Use.....................................................     7.45
High-Use.......................................................     7.53
------------------------------------------------------------------------

    DOE attempted this approach by obtaining an estimate of LF from 
data obtained during testing of 17 gas instantaneous water heaters 
according to the current simulated-use test. (LF could theoretically be 
determined for each unit, but some test results showed a recovery 
efficiency equal to EF, which would mathematically lead to an infinite 
value of LF). A regression of the energy consumption data during these 
tests with the quantity multiplying LF in the previous model equation 
resulted in a value of LF of 0.679 Btu/[deg]F. Using

[[Page 20128]]

this value to then estimate the energy consumption during the new 
simulated-use test resulted in predictions of the UEF. This approach 
resulted in a root mean squared error between predicted values and 
measured values of 0.027.
    Alternatively, a set of regressions, based solely on test data, 
were examined to determine the impact of other factors as discussed in 
section III.C.3. The best regressions resulted in a mean squared error 
of 0.032.
    As discussed for consumer storage water heaters in section 
III.C.2.c.i, DOE also considered a two-step process to convert the 
existing EF ratings to the UEF--first using the equations and 
assumptions described above to obtain an analytical prediction of UEF, 
then using a regression analysis to obtain a relationship that will 
convert from EF to UEF. Based on these results, DOE has chosen to use 
the analytical model plus a regression approach for converting EFs for 
consumer instantaneous water heaters to UEF. DOE has tentatively 
concluded that the assumptions made in the analytical model capture 
some key operating characteristics of the instantaneous units, and the 
further step to use measured data captures unforeseen issues. Details 
on this approach are provided in section III.C.3.
iii. Residential-Duty Commercial Water Heaters
    DOE investigated a modified version of WHAM for converting the 
thermal efficiency and standby loss metrics for residential-duty 
commercial storage water heaters to UEF. The AHRI certification 
directory includes the thermal efficiency (Et) and standby 
loss (SL). The equation below estimates the energy consumption of a 
water heater based on these efficiency metrics:
[GRAPHIC] [TIFF OMITTED] TP14AP15.012

where 70 represents the nominal temperature difference in degrees 
Fahrenheit between the tank and ambient during the standby loss test. 
By assuming that Ttank equals Tdel, all variables 
in the equation above are known, since Et and SL can be 
obtained from current ratings and all other variables are specified in 
the UEF test procedure for a given projected first-hour rating. The 
equation above can be used in combination with the one below to 
estimate the UEF for residential-duty storage water heaters 
(UEFrd):
[GRAPHIC] [TIFF OMITTED] TP14AP15.013

    These equations can be combined to yield the following equation for 
converting Et and SL to UEF using the coefficient C1, which 
is dependent upon the draw pattern applied during the UEF test, as 
provided in Table III.6.
[GRAPHIC] [TIFF OMITTED] TP14AP15.014


   Table III.6--Coefficient for Conversion of Commercial Water Heater
                             Ratings to UEF
------------------------------------------------------------------------
                      Draw pattern                              C1
------------------------------------------------------------------------
Very Small..............................................    3.575 x 10-3
Low.....................................................    9.408 x 10-4
Medium..................................................    6.500 x 10-4
High....................................................    4.256 x 10-4
------------------------------------------------------------------------

    As was done with consumer water heaters, DOE decided to account for 
unforeseen effects observed during testing by combining this analytical 
prediction with a regression of the predicted values of UEF to the 
measured UEF.
    DOE seeks comments on the use of analytical methods to convert 
existing metrics to the ones described in the July 2014 test procedure 
final rule. This is identified as issue 2 in section V.E, ``Issues on 
Which DOE Seeks Comment.''
3. Empirical Regression
    An alternative to the analytical approaches described in section 
III.C.2 is to develop empirical equations from measured metrics under 
the uniform efficiency descriptor test procedure to those obtained 
using the existing consumer and commercial water heater test 
procedures. This approach has the benefit of capturing the effects of 
factors that are not addressed in analytical models. The drawbacks of 
this approach are that it is susceptible to measurement errors and that 
it may not be easily extended to water heaters that were not part of 
the test program.
    To derive the conversion factors from an empirical regression, DOE 
first used a step regression method. The step regression method 
produces a linear equation which uses a set of observed independent 
variables, such as storage volume, input rate, delivery capacity, 
recovery efficiency, energy factor, thermal efficiency, or standby 
loss, and seeks to mathematically derive an equation using these 
variables to relate to a set of observed dependent variables, such as 
new delivery capacity (under the updated test method) and UEF. The step 
regression method systematically recombines the set of independent 
variables to produce an equation for each possible set. Each set's 
equation is compared to the others and the equation with the best fit 
is chosen. This approach eliminates factors that are not significant in 
converting existing metrics to the new metrics. DOE also considered 
simpler regression forms to reduce confusion in converting from old 
metrics to new metrics and to ensure that the regressions were 
applicable over the broad range of water heaters available on the 
market. In these circumstances, DOE examined the deviations between 
measured values and predicted values from the correction equations. 
When those deviations were comparable, DOE opted for simplified models 
that would be expected to capture the major phenomena that would affect 
the new metrics. The regression tool found in the Analysis ToolPak of 
Microsoft Excel (2010) was used to calculate the equation for each set 
of independent variables.
    As noted previously, because DOE has tentatively concluded that an 
empirical regression methodology would be more accurate than the 
analytical method described in section III.C.2 for determining first-
hour rating for storage water heaters, DOE has proposed conversion 
factors for those metrics and product types based on the use of the 
empirical regression methodology. DOE seeks comment on the use of the 
regression method for the conversion factor analysis. This is 
identified as issue 3 in section V.E, ``Issues on Which DOE Seeks 
Comment.''

D. Testing Conducted for the Mathematical Conversion

1. Consumer Water Heater Testing
    For its analysis of a mathematical conversion factor between the 
existing efficiency metrics and the uniform efficiency descriptor, DOE 
tested 43 consumer storage water heaters to both the existing and 
updated test procedures. Table III.7 and Table III.8

[[Page 20129]]

below summarize the units that have been tested. Table III.7 summarizes 
the units that have been tested according to heating type. Table III.8 
provides an estimate of the distribution of those units across draw 
pattern categories by using their first-hour ratings under the current 
test (although it is acknowledged that the applied draw pattern for a 
particular water heater could change under the new first-hour rating 
test).

 Table III.7--Consumer Storage Water Heater Test Distribution by Product
                                  Type
------------------------------------------------------------------------
                                                             Number of
                      Product type                         units tested
------------------------------------------------------------------------
Gas-fired...............................................              22
Oil-fired...............................................               2
Electric................................................              11
Heat Pump...............................................               6
Tabletop................................................               2
------------------------------------------------------------------------


  Table III.8--Consumer Storage Water Heater Test Distribution by Draw
                                 Pattern
------------------------------------------------------------------------
                                                             Number of
                     Draw pattern *                        units tested
------------------------------------------------------------------------
Very Small **...........................................               0
Low.....................................................               3
Medium..................................................              27
High....................................................              13
------------------------------------------------------------------------
* The draw pattern shown is based on the current rated values; actual
  draw patterns are dependent upon amended test procedure first-hour
  rating discussed in section III.C.1.
** No very small consumer storage water heaters covered under the
  existing test procedure were found on the market.

    DOE also tested 22 consumer instantaneous water heaters to develop 
the mathematical conversion for these products. Table III.9 below 
summarizes the units that have been tested. Table III.10 provides an 
estimate of the distribution of those units across draw patterns by 
using their maximum GPM ratings under the current test (although it is 
acknowledged that the applied draw pattern for a particular water 
heater could change under the new maximum GPM test).

  Table III.9--Consumer Instantaneous Water Heater Test Distribution by
                              Product Type
------------------------------------------------------------------------
                                                             Number of
                      Product type                         units tested
------------------------------------------------------------------------
Gas-fired *.............................................              17
Oil-fired **............................................               0
Electric................................................               5
------------------------------------------------------------------------
* Gas-fired water heaters include both natural gas and propane water
  heaters, as well as water heaters capable of using either natural gas
  or propane. DOE tested 10 natural gas water heaters, 1 propane water
  heaters, and 6 water heaters capable of using either natural gas or
  propane. Water heaters capable of using either fuel were tested with
  natural gas.
** No oil-fired consumer instantaneous water heaters were found to be on
  the market.


 Table III.10--Consumer Instantaneous Water Heater Test Distribution by
                              Draw Pattern
------------------------------------------------------------------------
                                                             Number of
                     Draw pattern *                        units tested
------------------------------------------------------------------------
Very Small..............................................               5
Low.....................................................               1
Medium..................................................               7
High....................................................               9
------------------------------------------------------------------------
* Draw pattern profiles are based on the rated values; actual draw
  patterns are dependent upon tested value discussed in section III.C.1.

2. Residential-Duty Commercial Water Heater Testing
    DOE tested 7 residential-duty commercial storage water heaters to 
develop the mathematical conversion for this equipment. Table III.11 
summarizes the units that have been tested. A table showing the 
distribution of draw pattern within the residential-duty commercial 
water heater test list is not available, because commercial water 
heaters currently do not have first-hour ratings.

   Table III.11--Residential-Duty Commercial Storage Water Heater Test
                      Distribution by Product Type
------------------------------------------------------------------------
                                                             Number of
                     Product type *                        units tested
------------------------------------------------------------------------
Gas-fired...............................................               7
Oil-fired **............................................               0
------------------------------------------------------------------------
* Heat pump and tabletop water heaters were not found on the market and,
  therefore, were not tested.
** One oil-fired unit failed during testing.

    As discussed in section III.B.2, DOE did not analyze a mathematical 
conversion for residential-duty commercial electric storage water 
heaters or residential-duty commercial instantaneous water heaters.

E. Testing Results and Analysis of Test Data

1. Impact of Certain Water Heater Attributes on Efficiency Ratings
    After conducting testing on all of the selected water heaters 
according to both the existing test procedures and the uniform 
efficiency descriptor test procedure, DOE examined how particular 
attributes of water heaters might affect the conversion factors and 
investigated the approaches discussed in section III.C for obtaining 
conversion factors. The goal of this analysis was to determine whether 
or not particular attributes necessitated separate conversion 
equations. Separate conversions were created for subsets of the tested 
units based on water heater attributes such as NOX emission 
level, short or tall configuration, vent type, standing pilot or 
electric ignition, if condensing or heat pump technology is used, and 
if the unit is tabletop. Additionally, conversion equations were also 
generated based on the full set of water heaters. To determine whether 
it was necessary to develop separate conversion factors for a 
particular attribute, the root-mean-square (RMS) of the difference 
between the measured values and the values obtained through various 
conversion methods was compared. The conversion approach with the 
lowest cumulative RMS value for a particular fuel type was considered 
to be the best candidate for the conversion equation.
    The three levels of NOX emissions currently available in 
water heaters on the market include standard (greater than or equal to 
40 nanograms per joule (ng/J)), low (less than 40 ng/J and greater than 
or equal to 10 ng/J for storage water heaters and greater than or equal 
to 14 ng/J for instantaneous water heaters) and ultra-low (less than 10 
ng/J for storage water heaters and less than 14 ng/J for instantaneous 
water heaters).
    Most units that are short or tall have been labeled as such by the 
manufacturer; however, some units do not have this designation. DOE has 
found that some units labeled as small are actually taller than units 
labeled as tall. DOE is interested in how manufacturers determine 
whether a unit is short or tall. This is identified as issue 4 in 
section V.E, ``Issues on Which DOE Seeks Comment.''
    The four venting configurations currently available in water 
heaters on the market include atmospheric, direct, power, and power-
direct. Atmospheric and power vent units intake air from the area 
surrounding the water heater, while direct and power-direct vents 
intake air from outdoors. Atmospheric and direct

[[Page 20130]]

vent units use natural convection to circulate combustion air, while 
power and power-direct vents use some additional method to force 
circulation of combustion air. Concentric inlet and outlet piping is a 
unique configuration that can be used in directly venting water heaters 
to preheat incoming air using exhaust gas. For these tests, concentric 
inlet and outlet piping was not used; inlet air for the direct and 
power-direct vent units was delivered to the water heater in separate 
pipes from that used for exhaust. As these tests were conducted under 
identical controlled conditions, DOE determined that there is very 
little difference between atmospheric and direct vent water heaters and 
also between power and power-direct vent. For these reasons DOE has 
grouped atmospheric and direct into the atmospheric configuration and 
power and power-direct into the power configuration.
    As an example of the process that was taken to examine the effect 
of these factors, Table III.12 shows the cumulative RMS values for the 
first-hour rating conversions for consumer storage water heaters. The 
rows in the table indicate how the conversion equations were separated 
out, and the columns provide the RMS for each class of consumer storage 
water heaters. For gas water heaters, these values show that the 
conversion approach that differentiates between condensing or non-
condensing technology and between NOX levels appears to 
provide the best approach considering its low RMS values. No other 
factors (e.g., short vs. tall, vent type, pilot type) were shown to 
have any significance on the effectiveness of the conversion factor. 
For oil-fired water heaters and electric water heaters, the lowest RMS 
deviations occurred when all units of that fuel type were considered, 
indicating that separating the conversion equations by tank shape was 
not necessary. The findings presented here for first-hour rating 
conversions are consistent with those for UEF. From these results, DOE 
proposes to develop conversion equations for consumer storage water 
heaters based on fuel type, with the gas units being further 
differentiated by whether or not they are condensing units and by their 
NOx emissions level ratings.
    For consumer instantaneous water heaters and residential-duty 
commercial water heaters, DOE found no dependence on factors such as 
condensing operation or vent type. Conversion factors for these classes 
of water heaters are, thus, based simply on fuel type.

         Table III.12--First-Hour Rating RMS Values by Water Heater Attribute for Consumer Water Heaters
----------------------------------------------------------------------------------------------------------------
                                            Gas-fired             Oil-fired                    Electric
----------------------------------------------------------------------------------------------------------------
All Units (All fuel types).............            6.99  6.89.......................  4.47.
All Units Short or Tall................            6.87  5.79.......................  3.67.
Fuel Type (Gas, Oil or Electric).......            7.16  Not enough units...........  3.88.
Fuel Type Short or Tall................            6.91  No short units.............  Not enough short units.
Fossil Fuel (Gas and Oil)..............            6.59  5.73.......................  N/A.
Fossil Fuel Short or Tall..............            6.52  5.82.......................  N/A.
Condensing or Non-Condensing...........            6.66  N/A........................  N/A.
NOX Type (Standard, Low or Ultra Low)..            4.61  N/A........................  N/A.
Vent Type (Atmospheric or Power).......            5.53  N/A........................  N/A.
Standing Pilot or Electric Ignition....            5.53  N/A........................  N/A.
Non-Condensing NOX Type and Separate               3.98  N/A........................  N/A.
 Condensing.
All Electric Types Separate............             N/A  N/A........................  3.43.
Heat Pump Separate.....................             N/A  N/A........................  3.59.
----------------------------------------------------------------------------------------------------------------

2. Conversion Factor Derivation
    DOE used the methods described in section III.C to derive the 
mathematical conversion factor for the different types of water heaters 
covered within the scope of this rulemaking (as discussed in section 
III.B). This section describes the methodology that was applied to 
develop a conversion factor for each type of water heater.
a. Consumer Storage Water Heaters
i. Test Results
    As stated in section III.D.1, DOE has conducted testing of 43 
consumer storage water heaters using both the current and new test 
procedures. Table III.13 below presents the test data used to derive 
the consumer storage water heater conversion factors. Table III.14 
shows the water heater attributes by unit described in section III.D.1.

                                                  Table III.13--Consumer Storage Water Heater Test Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     Current
                                                                 Storage     Input rate  Current FHR  Updated FHR    recovery
               Unit No.                         Type              volume      (Btu/h)       (gal)        (gal)      efficiency       EF          UEF
                                                                  (gal)                                                (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
CS-1.................................  Heat Pump.............         45.2       13,600         59.1         48.2        264.7        2.260        2.069
CS-2.................................  Heat Pump.............         45.5        8,500         57.3         57.0        269.0        2.272        2.575
CS-3.................................  Heat Pump.............         58.9        6,800         71.5         68.6        290.1        2.406        2.493
CS-4.................................  Heat Pump.............         77.6        6,800         90.5         87.1        285.0        2.315        2.641
CS-5.................................  Heat Pump.............         80.8        1,800         57.0         58.0        288.0        2.330        2.540
CS-6.................................  Electric..............         36.2       15,400         54.0         49.7         98.0        0.941        0.905
CS-7.................................  Electric..............         44.9       14,300         64.1         64.3         98.0        0.855        0.840
CS-8.................................  Electric..............         46.1       14,000         64.8         61.7         98.0        0.901        0.919
CS-9.................................  Electric..............         27.4       13,000         38.7         43.1         98.0        0.912        0.906
CS-10................................  Electric..............         34.1       14,000         50.7         52.0         98.0        0.902        0.907
CS-11................................  Electric..............         35.9       15,400         52.4         51.8         98.0        0.931        0.920

[[Page 20131]]

 
CS-12................................  Electric..............         36.1       15,400         53.2         54.8         98.0        0.912        0.927
CS-13................................  Electric..............         44.9       15,400         64.9         59.4         98.0        0.960        0.926
CS-14................................  Electric..............         45.8       15,400         62.7         64.2         98.0        0.922        0.936
CS-15................................  Electric..............         49.7       18,800         68.5         73.2         98.0        0.924        0.940
CS-16................................  Electric..............         72.2       14,700         88.7         80.9         98.0        0.848        0.883
CS-17................................  Tabletop..............         25.7       15,400         37.5         45.3         98.0        0.905        0.857
CS-18................................  Tabletop..............         35.1       15,400         52.9         47.8         98.0        0.878        0.804
CS-19................................  Gas...................         38.4       39,800         67.0         81.1         80.5        0.601        0.630
CS-20................................  Gas...................         49.5       44,100         97.4         86.6         80.5        0.610        0.634
CS-21................................  Gas...................         37.8       39,700         70.1         86.9         83.8        0.608        0.641
CS-22................................  Gas...................         47.6       49,900         90.2         81.0         81.1        0.674        0.675
CS-23................................  Gas...................         37.9       39,400         74.4         81.6         80.3        0.691        0.705
CS-24................................  Gas...................         38.0       32,600         66.9         58.5         69.0        0.574        0.566
CS-25................................  Gas...................         38.0       39,800         80.2         63.8         83.6        0.711        0.669
CS-26................................  Gas...................         38.1       40,800         73.5         75.2         83.6        0.702        0.716
CS-27................................  Gas...................         38.2       39,300         71.9         77.6         77.4        0.607        0.635
CS-28................................  Gas...................         27.9       31,600         58.8         64.4         80.7        0.620        0.606
CS-29................................  Gas...................         38.1       40,200         74.7         70.6         80.5        0.622        0.569
CS-30................................  Gas...................         38.3       37,900         71.9         64.6         78.5        0.616        0.434
CS-31................................  Gas...................         47.3       50,600         95.1         87.0         78.8        0.606        0.640
CS-32................................  Gas...................         38.6       40,100         70.2         67.2         80.4        0.673        0.647
CS-33................................  Gas...................         38.9       32,400         68.6         65.2         78.1        0.666        0.624
CS-34................................  Gas...................         27.9       59,000         96.9         94.5         78.2        0.702        0.709
CS-35................................  Gas...................         38.5       36,000         66.0         68.0         85.0        0.699        0.670
CS-36................................  Gas...................         47.8       64,600        107.9        108.8         79.5        0.649        0.672
CS-37................................  Gas...................         45.7       39,800         91.0         84.8         96.3        0.830        0.828
CS-38................................  Gas...................         38.2       40,300         68.2         64.8         79.7        0.606        0.595
CS-39................................  Gas...................         38.2       38,300         71.3         64.6         75.2        0.625        0.596
CS-40................................  Gas...................         47.8       40,500         94.2         83.8         74.0        0.550        0.641
CS-41................................  Gas...................         48.1       36,000         92.4         88.2         81.4        0.631        0.662
CS-42................................  Oil...................         29.8      105,300        104.8        111.7         71.4        0.518        0.478
CS-43................................  Oil...................         30.1      105,300        112.5        127.4         89.4        0.605        0.641
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                 Table III.14--Consumer Storage Water Heater Attributes
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                     Standing pilot or
            Unit No.                NOX emission level          Condensing               Vent type             Short or tall         electric ignition
--------------------------------------------------------------------------------------------------------------------------------------------------------
CS-1...........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-2...........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-3...........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-4...........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-5...........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-6...........................  N/A....................  N/A...................  N/A...................  Short.................  N/A.
CS-7...........................  N/A....................  N/A...................  N/A...................  Short.................  N/A.
CS-8...........................  N/A....................  N/A...................  N/A...................  Short.................  N/A.
CS-9...........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-10..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-11..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-12..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-13..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-14..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-15..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-16..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-17..........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-18..........................  N/A....................  N/A...................  N/A...................  N/A...................  N/A.
CS-19..........................  Standard...............  No....................  Atmospheric...........  Short.................  Yes.
CS-20..........................  Standard...............  No....................  Atmospheric...........  Short.................  Yes.
CS-21..........................  Standard...............  No....................  Atmospheric...........  Tall..................  Yes.
CS-22..........................  Standard...............  No....................  Power.................  Tall..................  No.
CS-23..........................  Low....................  No....................  Atmospheric...........  Short.................  No.
CS-24..........................  Low....................  No....................  Atmospheric...........  Short.................  Yes.
CS-25..........................  Low....................  No....................  Atmospheric...........  Tall..................  No.
CS-26..........................  Low....................  No....................  Atmospheric...........  Tall..................  No.
CS-27..........................  Low....................  No....................  Atmospheric...........  Tall..................  No.
CS-28..........................  Low....................  No....................  Atmospheric...........  Tall..................  Yes.
CS-29..........................  Low....................  No....................  Atmospheric...........  Tall..................  Yes.
CS-30..........................  Low....................  No....................  Atmospheric...........  Tall..................  Yes.

[[Page 20132]]

 
CS-31..........................  Low....................  No....................  Atmospheric...........  Tall..................  Yes.
CS-32..........................  Low....................  No....................  Power.................  Short.................  No.
CS-33..........................  Low....................  No....................  Power.................  Short.................  No.
CS-34..........................  Low....................  No....................  Power.................  Tall..................  No.
CS-35..........................  Low....................  No....................  Power.................  Tall..................  No.
CS-36..........................  Low....................  No....................  Power.................  Tall..................  No.
CS-37..........................  Low....................  Yes...................  Power.................  Tall..................  No.
CS-38..........................  Ultra-Low..............  No....................  Atmospheric...........  Short.................  Yes.
CS-39..........................  Ultra-Low..............  No....................  Atmospheric...........  Short.................  Yes.
CS-40..........................  Ultra-Low..............  No....................  Atmospheric...........  Tall..................  Yes.
CS-41..........................  Ultra-Low..............  No....................  Atmospheric...........  Tall..................  Yes.
CS-42..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
CS-43..........................  N/A....................  N/A...................  N/A...................  Tall..................  N/A.
--------------------------------------------------------------------------------------------------------------------------------------------------------

ii. Conversion Factor Results
    For consumer storage water heaters, DOE proposes to use the 
regression method described in section III.C.3 to develop new first 
hour ratings. Of the factors considered, DOE found that the existing 
first hour rating was the best overall predictor of the new first hour 
rating. These findings were based on the root mean squared errors 
between predictions and measured values. In some cases, addition of 
other factors in the regressions (e.g., input rate, storage volume) led 
to predictions with slightly better RMS values, but DOE chose to be 
consistent in its formulations by using the same factor, existing first 
hour ratings. In these cases, DOE found that addition of extra terms 
improved the RMS value by less than 1 gallon, so it tentatively 
concluded that the added potential for confusion is not warranted. The 
resulting equations for determining the FHRnew of consumer 
storage water heaters are:

New FHRGas,Non-Condensing,Standard NOx = 1.0085 * FHREx

New FHRGas,Non-Condensing,Low NOx = 4.6894 + 0.9112 * FHREx

New FHRGas,Non-Condensing,Ultra	Low NOx = 2.9267 + 0.8882 * FHREx

New FHRGas,Condensing = -0.7072 + 0.9724 * FHREx

New FHROil = 1.1018 * FHREx

New FHRElectric,Conventional&Tabletop = 11.9239 + 0.7879 * FHREx

New FHRElectric,Heat Pump = -2.3440 + 0.9856 * FHREx

where FHRnew is the new first hour rating, FHRex 
is the existing first hour rating, and the slope and intercept are 
constants obtained from a linear regression. While most of the data 
allowed for such a regression fit, in two cases (oil, non-condensing 
gas with standard level NOX burners) the available data were 
too limited to produce reliable regressions. In these cases, the 
intercepts of the regressions were assigned a value of zero, meaning 
that a water heater with an FHRex of zero would also have an 
FHRnew of zero.
    The next step in the conversion is to determine which draw pattern 
is to be applied to convert from EF to UEF. After the first-hour rating 
under the uniform efficiency descriptor is determined through the 
conversion factor above, the value can be applied to determine the 
appropriate draw pattern bin (i.e., very small, low, medium, or high) 
using Table III.3 of this NOPR or Table 1 of the uniform efficiency 
descriptor test procedure. 79 FR 40542, 40572 (July 11, 2014). With the 
draw bin known, the UEF value based on the WHAM analytical model can be 
calculated using the process described in section III.C.2.c.i for all 
types except for heat pump water heaters. Alternatively, DOE 
investigated the step regression approach described in section III.C.3 
to convert EF to UEF. DOE found that a third technique, a combination 
of these approaches in which the results of the WHAM analytical model 
are used as the independent variable in a standard linear regression 
analysis, produced the best results. Separate conversion equations were 
developed for the same categories as used for first-hour rating. The 
results of the first-hour regression, the WHAM analytical model, the 
step regression model, and the combined WHAM-regression model are 
presented below in Table III.16. The RMS errors for the classes range 
from 0.0014 to 0.0495 when using a combined WHAM-regression model. For 
heat pump water heaters, a linear regression in which the UEF is 
estimated solely from the existing EF results in an RMS error of 0.187. 
Considering the larger magnitude of UEFs for heat pump water heaters, 
DOE has tentatively concluded that this relatively high RMS error is 
acceptable for heat pump water heaters. DOE has, therefore, tentatively 
decided to use the combined WHAM-regression approach to calculate the 
consumer storage water heater conversion factor for non-heat pump water 
heaters and to apply a regression that relates UEF to EF for heat pump 
water heaters. The WHAM-regression approach accounts for the test 
procedure changes in terms of daily volume delivered and storage tank 
temperature, and it corrects for the unaccounted changes using a 
regression with actual test data. Because the data are not believed to 
be publicly available to compute the WHAM estimate for heat pump water 
heaters, DOE proposes to base this conversion on an empirical 
regression. The resulting equations for determining the UEF of consumer 
storage water heaters are:
[GRAPHIC] [TIFF OMITTED] TP14AP15.015

UEFGas,Non-Condensing,Standard NOx = 0.2726 * UEFWHAM + 0.4736

UEFGas,Non-Condensing,Low NOx = 0.9966 * UEFWHAM - 0.0126

UEFGas,Non-Condensing,Ultra-Low NOx = 0.5811 *UEFWHAM + 0.2673


[[Page 20133]]


UEFGas,Condensing = 0.9164 * UEFWHAM + 0.0409

UEFOil = 1.1185 * UEFWHAM - 0.0945

UEFElectric,Conventional&Tabletop = 0.8673 * UEFWHAM + 0.1227

UEFElectric,Heat Pump = 1.5485 * EF - 1.1235

where UEFWHAM is the conversion factor calculated using the 
WHAM analytical model and the coefficient values shown in Table III.15, 
P is the nameplate input rate in Btu/h, and [eta]r is the 
recovery efficiency expressed in decimal form (e.g., 0.98 instead of 98 
[%]).

                         Table III.15--Coefficients for WHAM-Based UEF Conversion Factor
----------------------------------------------------------------------------------------------------------------
                    Draw bin                             a               b               c               d
----------------------------------------------------------------------------------------------------------------
Very Small......................................        56095146     12884892499         8930623     15125743368
Low.............................................        56095146     48962591496        33936368     57477824799
Medium..........................................        56095146     70866908744        49118427     83191588525
High............................................        56095146    108233096990        75017235    127056244293
----------------------------------------------------------------------------------------------------------------


                      Table III.16--Consumer Storage Water Heater Conversion Factor Results
----------------------------------------------------------------------------------------------------------------
                                                                                                        WHAM-
          Unit No.             Tested FHR    Regression    Tested  UEF    WHAM  UEF    Regression    Regression
                                  (gal)       FHR (gal)                                    UEF           UEF
----------------------------------------------------------------------------------------------------------------
CS-1........................          48.2          55.9         2.069         2.209         2.375         2.384
CS-2........................          57.0          54.1         2.575         2.215         2.395         2.391
CS-3........................          68.6          68.1         2.493         2.339         2.603         2.525
CS-4........................          87.1          86.9         2.641         2.435         2.461         2.630
CS-5........................          58.0          53.8         2.540         2.213         2.484         2.388
CS-6........................          49.7          54.4         0.905         0.935         0.930         0.933
CS-7........................          64.3          62.4         0.840         0.836         0.875         0.847
CS-8........................          61.7          62.9         0.919         0.888         0.904         0.893
CS-9........................          43.1          42.4         0.906         0.866         0.911         0.874
CS-10.......................          52.0          51.8         0.907         0.888         0.905         0.893
CS-11.......................          51.8          53.2         0.920         0.923         0.923         0.923
CS-12.......................          54.8          53.9         0.927         0.901         0.911         0.904
CS-13.......................          59.4          63.0         0.926         0.956         0.941         0.952
CS-14.......................          64.2          61.4         0.936         0.912         0.917         0.914
CS-15.......................          73.2          65.9         0.940         0.915         0.919         0.916
CS-16.......................          80.9          81.8         0.883         0.880         0.871         0.885
CS-17.......................          45.3          41.5         0.857         0.855         0.896         0.864
CS-18.......................          47.8          53.6         0.804         0.862         0.873         0.870
CS-19.......................          81.1          67.5         0.630         0.578         0.632         0.631
CS-20.......................          86.6          98.3         0.634         0.651         0.637         0.651
CS-21.......................          86.9          70.7         0.641         0.583         0.636         0.632
CS-22.......................          81.0          91.0         0.675         0.705         0.675         0.666
CS-23.......................          81.6          72.5         0.705         0.676         0.683         0.661
CS-24.......................          58.5          65.6         0.566         0.558         0.571         0.544
CS-25.......................          63.8          77.8         0.669         0.739         0.702         0.724
CS-26.......................          75.2          71.6         0.716         0.685         0.694         0.670
CS-27.......................          77.6          70.2         0.635         0.587         0.603         0.572
CS-28.......................          64.4          58.3         0.606         0.598         0.616         0.583
CS-29.......................          70.6          72.8         0.569         0.600         0.617         0.585
CS-30.......................          64.6          70.2         0.434         0.595         0.611         0.580
CS-31.......................          87.0          91.4         0.640         0.645         0.602         0.630
CS-32.......................          67.2          68.6         0.647         0.656         0.666         0.641
CS-33.......................          65.2          67.2         0.624         0.651         0.660         0.636
CS-34.......................          94.5          93.0         0.709         0.721         0.694         0.706
CS-35.......................          68.0          64.8         0.670         0.679         0.690         0.664
CS-36.......................         108.8         103.0         0.672         0.681         0.643         0.666
CS-37.......................          84.8          87.8         0.828         0.861         0.824         0.830
CS-38.......................          64.8          63.5         0.595         0.583         0.592         0.606
CS-39.......................          64.6          66.3         0.596         0.609         0.599         0.621
CS-40.......................          83.8          86.6         0.641         0.589         0.653         0.610
CS-41.......................          88.2          85.0         0.662         0.670         0.649         0.656
CS-42.......................         111.7         115.5         0.478         0.557         0.537         0.529
CS-43.......................         127.4         123.9         0.641         0.659         0.613         0.643
----------------------------------------------------------------------------------------------------------------

b. Consumer Instantaneous
i. Test Results
    As stated in section III.D.1, DOE has tested 22 consumer 
instantaneous water heaters to both the current and new test 
procedures. Table III.17 presents the test data used to derive the 
consumer instantaneous water heater conversion factors. It is noted 
that test results show measured recovery efficiencies above 100 percent 
and EFs and UEFs above 1 for electric instantaneous units; DOE 
acknowledges that these results appear to violate theoretical limits 
and believes that these results are an artifact of measurement 
uncertainty. Table III.18 shows the water heater attributes by unit 
described in section III.D.1.

[[Page 20134]]



                                               Table III.17--Consumer Instantaneous Water Heater Test Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              Current
             Unit No.                       Type            Input rate      Current max     Updated max      recovery           EF              UEF
                                                              (Btu/h)           GPM             GPM       efficiency (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
CI-1..............................  Electric............           8,200            0.20            0.23           101.2           1.012           0.982
CI-2..............................  Electric............          32,400            0.82            0.93           101.5           1.017           0.981
CI-3..............................  Electric............          34,100            0.87            0.99           101.8           1.018           1.001
CI-4..............................  Electric............          27,300            0.68            0.80           102.0           1.019           1.004
CI-5..............................  Electric............          20,500            0.52            0.59           102.3           1.021           1.005
CI-6..............................  Gas.................         179,900            4.01            4.58            82.4           0.821           0.832
CI-7..............................  Gas.................         178,500            4.08            4.71            83.8           0.837           0.828
CI-8..............................  Gas.................         120,900            2.69            3.07            84.1           0.839           0.814
CI-9..............................  Gas.................         199,000            4.61            4.86            87.0           0.876           0.841
CI-10.............................  Gas.................         151,900            3.47            3.96            88.3           0.891           0.815
CI-11.............................  Gas.................         141,100            3.11            3.61            81.4           0.810           0.824
CI-12.............................  Gas.................         190,400            4.23            4.81            83.4           0.829           0.818
CI-13.............................  Gas.................         142,500            2.96            3.43            80.9           0.801           0.795
CI-14.............................  Gas.................         197,200            5.19            5.80            96.7           0.966           0.958
CI-15.............................  Gas.................         199,800            4.80            4.10            93.8           0.932           0.931
CI-16.............................  Gas.................         151,500            3.24            3.88            84.3           0.837           0.805
CI-17.............................  Gas.................         180,400            3.92            4.60            85.0           0.853           0.827
CI-18.............................  Gas.................         175,800            3.67            4.30            84.5           0.838           0.830
CI-19.............................  Gas.................         199,200            4.30            5.07            75.0           0.743           0.799
CI-20.............................  Gas.................         154,100            3.98            4.47            91.6           0.913           0.922
CI-21.............................  Gas.................         201,300            4.90            5.70            88.0           0.851           0.884
CI-22.............................  Gas.................         199,900            5.12            4.91            89.9           0.888           0.943
--------------------------------------------------------------------------------------------------------------------------------------------------------


                          Table III.18--Consumer Instantaneous Water Heater Attributes
----------------------------------------------------------------------------------------------------------------
              Unit No.                 NOX emission level          Condensing                 Vent type
----------------------------------------------------------------------------------------------------------------
CI-1...............................  N/A...................  N/A...................  N/A.
CI-2...............................  N/A...................  N/A...................  N/A.
CI-3...............................  N/A...................  N/A...................  N/A.
CI-4...............................  N/A...................  N/A...................  N/A.
CI-5...............................  N/A...................  N/A...................  N/A.
CI-6...............................  Low...................  No....................  Atmospheric.
CI-7...............................  Low...................  No....................  Atmospheric.
CI-8...............................  Low...................  No....................  Atmospheric.
CI-9...............................  Low...................  No....................  Atmospheric.
CI-10..............................  Low...................  No....................  Atmospheric.
CI-11..............................  Low...................  No....................  Power.
CI-12..............................  Low...................  No....................  Power.
CI-13..............................  Low...................  No....................  Power.
CI-14..............................  Low...................  Yes...................  Atmospheric.
CI-15..............................  Low...................  Yes...................  Atmospheric.
CI-16..............................  Ultra-Low.............  No....................  Atmospheric.
CI-17..............................  Ultra-Low.............  No....................  Atmospheric.
CI-18..............................  Ultra-Low.............  No....................  Atmospheric.
CI-19..............................  Ultra-Low.............  No....................  Atmospheric.
CI-20..............................  Ultra-Low.............  Yes...................  Atmospheric.
CI-21..............................  Ultra-Low.............  Yes...................  Atmospheric.
CI-22..............................  Ultra-Low.............  Yes...................  Power.
----------------------------------------------------------------------------------------------------------------

ii. Conversion Factor Results
    As stated in section III.C.2, DOE developed an analytical model to 
convert the existing maximum GPM rating for consumer instantaneous 
water heaters to ratings under the uniform efficiency descriptor test 
procedure. DOE also attempted to develop an analytical method based on 
the WHAM equation to estimate the change in existing energy factor 
ratings under the existing consumer water heater test procedure to 
values under the uniform efficiency descriptor test procedure. Along 
with this analytical model, step regression and combined analytical 
model-regression approaches were conducted. The results of the 
analytical model, step regression, and combined analytical model-
regression approaches for the maximum GPM and UEF conversions are 
presented in Table III.20. For the maximum GPM conversions, the RMS 
errors for the three approaches are 0.38, 0.35, and 0.38, respectively. 
For the UEF conversions, the three approaches have RMS errors of 0.024, 
0.028, and 0.023, respectively. DOE has tentatively decided to use the 
analytical model approach to calculate the consumer instantaneous 
maximum GPM conversion factor owing to the fact that the model predicts 
the resultant data very closely and that it will broadly apply to those 
units not tested. DOE has also tentatively decided to use the combined 
analytical model-regression approach to convert from EF to UEF since 
the RMS errors are low, and it has tentatively concluded that the use 
of the model and regression will capture key

[[Page 20135]]

effects that may not be captured with either approach by itself. For 
the electric instantaneous water heaters, DOE imposed a zero intercept 
on the regression since the regression with an intercept resulted in 
UEFs above the theoretical limit of 1. DOE has tentatively concluded 
that this step is technically acceptable, as it effectively states that 
a water heater with an EF of zero should also have a UEF of zero. The 
resulting conversion factors for both first hour rating and UEF are:

MaxGPMnew = 1.147 * MaxGPMEx

UEFgas = 0.9059 * UEFmodel + 0.0783

UEFelectric = 1.0079 * UEFmodel

where MaxGPMEx is the maximum GPM rating based on the 
current DOE test procedure and UEFmodel is the predicted UEF 
determined using the following analytical model:
[GRAPHIC] [TIFF OMITTED] TP14AP15.016

Values for the coefficients A and B are dependent upon the draw pattern 
applied during the simulated-use test and are provided in Table III.19.

      Table III.19--Coefficients To Determine UEFmodel for Consumer
                       Instantaneous Water Heaters
------------------------------------------------------------------------
                     Draw bin                           A          B
------------------------------------------------------------------------
Very Small........................................     5514.2      170.2
Low...............................................      20954      262.4
Medium............................................      30328      290.9
High..............................................      46319      294.0
------------------------------------------------------------------------


                                       Table III.20--Consumer Instantaneous Water Heater Conversion Factor Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Combined
                                           Tested max    Analytical    Regression    analytical-                 Analytical    Regression    Analytical-
                Unit No.                       GPM         max GPM       max GPM     regression    Tested UEF        UEF           UEF       regression
                                                                                       max GPM                                                   UEF
--------------------------------------------------------------------------------------------------------------------------------------------------------
CI-1....................................          0.23          0.23          0.24          0.23         0.982         0.982         0.980         0.989
CI-2....................................          0.93          0.94          0.94          0.94         0.981         0.984         0.987         0.992
CI-3....................................          0.99          1.00          1.00          1.00         1.001         0.987         0.995         0.995
CI-4....................................          0.80          0.78          0.78          0.78         1.004         0.989         1.001         0.997
CI-5....................................          0.59          0.59          0.60          0.59         1.005         0.991         1.008         0.999
CI-6....................................          4.58          4.60          4.58          4.60         0.832         0.820         0.816         0.820
CI-7....................................          4.71          4.68          4.66          4.68         0.828         0.834         0.829         0.833
CI-8....................................          3.07          3.08          3.17          3.08         0.814         0.834         0.830         0.834
CI-9....................................          4.86          5.28          5.22          5.28         0.841         0.865         0.859         0.861
CI-10...................................          3.96          3.98          4.01          3.98         0.815         0.878         0.871         0.873
CI-11...................................          3.61          3.56          3.62          3.56         0.824         0.808         0.807         0.810
CI-12...................................          4.81          4.85          4.82          4.85         0.818         0.829         0.822         0.829
CI-13...................................          3.43          3.39          3.46          3.39         0.795         0.803         0.800         0.805
CI-14...................................          5.80          5.95          5.84          5.95         0.958         0.961         0.931         0.948
CI-15...................................          4.10          5.50          5.43          5.50         0.931         0.933         0.904         0.923
CI-16...................................          3.88          3.71          3.76          3.71         0.805         0.836         0.829         0.835
CI-17...................................          4.60          4.49          4.49          4.49         0.827         0.845         0.841         0.844
CI-18...................................          4.30          4.21          4.22          4.21         0.830         0.840         0.829         0.839
CI-19...................................          5.07          4.93          4.90          4.93         0.799         0.746         0.754         0.754
CI-20...................................          4.47          4.56          4.55          4.56         0.922         0.911         0.889         0.903
CI-21...................................          5.70          5.62          5.54          5.62         0.884         0.875         0.840         0.870
CI-22...................................          4.91          5.87          5.77          5.87         0.943         0.894         0.869         0.887
--------------------------------------------------------------------------------------------------------------------------------------------------------

c. Residential-Duty Commercial Storage Testing
i. Test Data
    As stated in section III.D.2, DOE has tested 7 residential-duty 
commercial storage water heaters to both the current and new test 
procedures. Table III.21 below presents the test data used to derive 
the residential-duty commercial storage water heater conversion 
factors. Table III.22 shows the water heater attributes by unit 
described in section III.D.2.

                                        Table III.21--Residential-Duty Commercial Storage Water Heater Test Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Storage       Input rate    Tested thermal  Tested standby    Updated FHR
             Unit No.                       Type           volume (gal)       (Btu/h)     efficiency (%)   loss (Btu/h)        (gal)            UEF
--------------------------------------------------------------------------------------------------------------------------------------------------------
RD-1.............................  Gas..................            95.4          79,100            80.4         1,178.2           109.8           0.514
RD-2.............................  Gas..................            72.7          67,400            67.9           721.0            90.3           0.585
RD-3.............................  Gas..................            71.3          69,700            75.5           839.4           119.3           0.619
RD-4.............................  Gas..................            48.3          76,500            93.6           328.0           137.0           0.816
RD-5.............................  Gas..................            48.4          75,300            88.9           338.1           126.5           0.725
RD-6.............................  Gas..................            47.8          75,700            90.0           358.4           103.3           0.621
RD-7.............................  Gas..................            71.0          63,800            67.1         1,546.8           111.5           0.470
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 20136]]


                                        Table III.22--Residential-Duty Commercial Storage Water Heater Attributes
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                     Standing pilot or
            Unit No.                NOX emission level          Condensing               Vent type             Short or tall         electric ignition
--------------------------------------------------------------------------------------------------------------------------------------------------------
RD-1...........................  Standard...............  No....................  Atmospheric...........  Tall..................  Yes.
RD-2...........................  Standard...............  No....................  Power.................  Tall..................  No.
RD-3...........................  Standard...............  No....................  Power.................  Tall..................  No.
RD-4...........................  Low....................  Yes...................  Atmospheric...........  Short.................  No.
RD-5...........................  Low....................  Yes...................  Power.................  Tall..................  No.
RD-6...........................  Low....................  Yes...................  Power.................  Tall..................  No.
RD-7...........................  Ultra-Low..............  No....................  Atmospheric...........  Tall..................  Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

ii. Conversion Factor Results
    As stated in section III.C.2.b, DOE is not aware of an analytical 
model to convert the thermal efficiency and standby loss ratings under 
the current test procedure to first-hour rating values under the new 
test procedure. Therefore, the step regression method described in 
section III.C.3 along with the best combination of water heater 
attributes were used to determine the following first-hour rating 
conversion factors:

New FHRFossil Fuel = 1.0226 * Q + 39.81

Where Q is the input rate of the burner in kBtu/h. For this regression, 
DOE decided to group both oil and gas water heaters because of the lack 
of oil water heaters identified. DOE has tentatively concluded that 
this grouping is the best approach to convert ratings for any 
residential-duty oil water heater on the market.
    The next step in the conversion is to determine which draw pattern 
is to be applied to convert to UEF. After the first-hour rating under 
the uniform efficiency descriptor is determined through the conversion 
factor above, the value can be applied to determine the appropriate 
draw pattern bin (i.e., very small, low, medium, or high) using Table 
III.3 of this NOPR or Table 1 of the uniform efficiency descriptor test 
procedure. 79 FR 40542, 40572 (July 11, 2014). With the draw bin known, 
the UEF value based on the analytical model can be calculated using the 
process described in section III.C.2.c.iii. The analytical results, 
along with the results of the step regression and analytical-regression 
are shown in Table III.23 and have RMS values of 0.074, 0.055, and 
0.053, respectively. Based on these results, DOE has tentatively 
decided to use the combined analytical-regression approach to calculate 
the residential-duty commercial storage water heater conversion factor. 
While the regression approach yields a slightly better RMS error, DOE 
has tentatively concluded that the use of the analytical model will 
make the conversion more robust over the entire family of residential-
duty commercial storage water heaters since it captures the effects of 
water temperature, draw volume per day, thermal efficiency, and standby 
loss that are expected to be valid for any water heater. Thus, the use 
of an analytical model is expected to be less prone to error should a 
model have some unexpected characteristic that was not captured in the 
water heaters tested as part of this NOPR. The resulting equations for 
determining the UEF of consumer storage water heaters are:

UEFfossil fuel = 0.7300 * UEFrd + 0.1413

Where UEFrd is the estimate of the UEF for residential-duty 
water heaters computed with the following equation:
[GRAPHIC] [TIFF OMITTED] TP14AP15.017

where C1 is a constant dependent upon the draw pattern given 
in Table III.6, Et is the thermal efficiency in fractional 
form (i.e., 0.85 instead of 85 (%)), and SL is the standby loss in BTU/
h.

                                           Table III.23--Residential-Duty Commercial Conversion Factor Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Tested FHR     Regression FHR                                                       Analytical-
                     Unit No.                            (gal)            (gal)          Tested UEF     Analytical UEF   Regression UEF   regression UEF
--------------------------------------------------------------------------------------------------------------------------------------------------------
RD-1..............................................            109.8            120.7            0.514            0.573            0.530            0.560
RD-2..............................................             90.3            108.8            0.585            0.562            0.629            0.551
RD-3..............................................            119.3            111.1            0.619            0.595            0.604            0.575
RD-4..............................................            137.0            118.0            0.816            0.828            0.715            0.746
RD-5..............................................            126.5            116.9            0.725            0.788            0.713            0.717
RD-6..............................................            103.3            117.3            0.621            0.791            0.709            0.719
RD-7..............................................            111.5            105.0            0.470            0.466            0.449            0.481
--------------------------------------------------------------------------------------------------------------------------------------------------------

d. Residential-Duty Instantaneous Testing
    As discussed in section III.B.2, no instantaneous residential-duty 
commercial water heaters exist on the market. Therefore, a conversion 
factor is not needed.
3. Energy Conservation Standard Derivation
    After developing the mathematical conversion factors to convert 
from the existing efficiency ratings to the efficiency ratings under 
the UEF metric, DOE sought to update its energy conservation standards 
for covered water heater products so as to be in terms of UEF. DOE 
investigated several possible methods to determine the appropriate 
energy conservation standards in terms of UEF.
    First, DOE considered the ``percent difference'' method, which is 
the method DOE ultimately has proposed for updating the energy 
conservation standards so as to be based on the UEF metric. The percent 
difference method was conducted as follows:
    1. Apply conversion factor to convert the current efficiency 
metrics provided in the relevant consumer or commercial database to the 
calculated UEF value for each water heater on the market.
    2. Calculate the current efficiency standard for each water heater 
in the database, as follows:

[[Page 20137]]

    a. For consumer water heaters, find the minimum EF.
    b. For residential-duty commercial water heaters, find the minimum 
thermal efficiency.
    3. Find the percent difference between the rated efficiency value 
and the standard for each water heater in the database, as follows:
[GRAPHIC] [TIFF OMITTED] TP14AP15.018

    4. Find the new energy conservation standard for each water heater 
in the database, as follows:

a. UEFmin = UEF (1 - PD)

    5. Find a line through their minimum UEF values.
    The advantage of using a ``percent difference'' is that the updated 
energy conservation standard is a function of the UEF conversion for 
all water heaters rather than a subset. It also allows for conversions 
of standards for classes or groupings of water heaters where no 
minimally compliant models are currently available on the market. The 
proposed standards in terms of uniform energy factor are shown below by 
product class and draw pattern.

                    Table III.24--Updated Consumer Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
                                  Rated storage
         Product class                volume              Draw pattern               Uniform energy factor
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage.............  >=20 gal and <=55  Very Small...............  0.3263 - (0.0019 x Vr)
                                 gal.
                                                   Low......................  0.5891 - (0.0019 x Vr)
                                                   Medium...................  0.6326 - (0.0013 x Vr)
                                                   High.....................  0.7128 - (0.0025 x Vr)
                                >55 gal and <=100  Very Small...............  0.5352 - (0.0007 x Vr)
                                 gal.
                                                   Low......................  0.7375 - (0.0009 x Vr)
                                                   Medium...................  0.7704 - (0.0010 x Vr)
                                                   High.....................  0.7980 - (0.0010 x Vr)
Oil-fired Storage.............  <=50 gal.........  Very Small...............  0.2267 - (0.0014 x Vr)
                                                   Low......................  0.4867 - (0.0006 x Vr)
                                                   Medium...................  0.6016 - (0.0012 x Vr)
                                                   High.....................  0.6529 - (0.0005 x Vr)
Electric Storage..............  >=20 gal and <=55  Very Small...............  0.8268 - (0.0002 x Vr)
                                 gal.
                                                   Low......................  0.9393 - (0.0004 x Vr)
                                                   Medium...................  0.9683 - (0.0007 x Vr)
                                                   High.....................  0.9656 - (0.0004 x Vr)
                                >55 gal and <=120  Very Small...............  1.2701 - (0.0011 x Vr)
                                 gal.
                                                   Low......................  1.9137 - (0.0011 x Vr)
                                                   Medium...................  2.0326 - (0.0011 x Vr)
                                                   High.....................  2.1858 - (0.0011 x Vr)
Tabletop Storage..............  >=20 gal and       Very Small...............  0.6808 - (0.0022 x Vr)
                                 <=100 gal.
                                                   Low......................  0.8770 - (0.0012 x Vr)
                                                   Medium...................  0.9063 - (0.0009 x Vr)
                                                   High.....................  0.9302 - (0.0006 x Vr)
Gas-fired Instantaneous.......  <2 gal...........  All......................  0.8036 - (0.0019 x Vr)
Electric Instantaneous........  <2 gal...........  All......................  0.9192 - (0.0013 x Vr)
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.


          Table III.25--Updated Residential-Duty Commercial Water Heater Energy Conservation Standards
----------------------------------------------------------------------------------------------------------------
            Product class                        Draw pattern                     Uniform energy factor
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage....................  Very Small.....................  0.3261 - (0.0006 x Vr)
                                       Low............................  0.5219 - (0.0008 x Vr)
                                       Medium.........................  0.5585 - (0.0006 x Vr)
                                       High...........................  0.6044 - (0.0005 x Vr)
Oil-fired Storage....................  Very Small.....................  0.3206 - (0.0006 x Vr)
                                       Low............................  0.5577 - (0.0019 x Vr)
                                       Medium.........................  0.6027 - (0.0019 x Vr)
                                       High...........................  0.6446 - (0.0018 x Vr)
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume which equals the water storage capacity of a water heater (in gallons), as
  specified by the manufacturer.

    As stated in section III.A, EEI commented in response to the 
November 2013 NOPR, that the updated energy conservation standards 
should be not more stringent than they are currently. The percent 
difference from the current rated energy factors and energy 
conservation standards are used to derive the new energy conservation

[[Page 20138]]

standards; therefore, the updated standards are no more stringent than 
those currently in existence. A.O. Smith and AHRI suggested that the 
average difference between the current and new ratings should not be 
used to convert the energy conservation standards. At no point in the 
conversion factor derivation or energy conservation standard analysis 
is a simple average taken, but rather, the trends of all the 
traditional factors affecting water heaters are considered.
    DOE also investigated a second method of determining the energy 
conservation standards where only test data from minimally-compliant 
water heaters would be used to develop a conversion factor using the 
analytical and regression methods described in section III.C. Then, 
this set of conversion factors could be applied to the minimum energy 
conservation standards to determine the appropriate energy conservation 
standards in terms of the UEF metric. This method would remove from 
consideration any factors that are present in more-efficient water 
heaters, so the resulting change in the standard would not be skewed at 
all by the inclusion of higher-efficiency products in the mathematical 
conversion. However, the conversion factors developed through such a 
methodology would potentially not be applicable for converting the 
efficiency ratings of products above the baseline. Therefore, DOE chose 
to pursue a methodology that was applicable to all water heaters and 
perform the conversion of standards based on the ``percent difference'' 
method described above.
    DOE seeks comment on the most appropriate method for determining 
the energy conservation standards based on the updated test procedure. 
This is identified as issue 5 in section V.E, ``Issues on Which DOE 
Seeks Comment.''

F. Certification and Labeling Issues

    Consumer water heaters and residential-duty commercial water 
heaters manufactured prior to the effective date of the uniform energy 
factor test procedure final rule (i.e., July 13, 2015) that comply with 
the efficiency standards and labeling requirements in effect prior to 
that final rule will be considered to comply with the converted UEF 
standards and with any revised labeling requirements established by the 
Federal Trade Commission (FTC) to carry out the final rule. (42 U.S.C. 
6295(e)(5)(K)) The statute requires that the standard be in terms of 
UEF as of July 13, 2015. Accordingly, DOE proposes to require 
manufacturers to provide EF and UEF for consumer water heaters (or 
thermal efficiency and standby loss and UEF for commercial residential-
duty water heaters) in certification reports filed between July 13, 
2015, and the compliance date determined by the final rule in this 
rulemaking. Manufacturers would not be required to submit revised 
certification reports for previously certified basic models until the 
next annual certification date (May 1).
    Allowing manufacturers to submit both EF and UEF data would allow 
manufacturers to fulfill the statutory requirement to begin using UEF 
for purposes of compliance with standards but would also allow 
manufacturers to provide the necessary information to determine costs 
under the current FTC labeling requirements. This would also allow a 
transition period for FTC to pursue a rulemaking to determine whether 
changes are needed to the water heater EnergyGuide label due to changes 
in the water heater test procedure. DOE expects that the conversion 
factors proposed in this notice could be used to convert EF to UEF for 
previously certified basic models or to convert UEF values 
``backwards'' to EF to determine the appropriate costs for labeling of 
new basic models until FTC has determined whether to make changes to 
the label. DOE has proposed a methodology for calculating costs based 
on UEF testing that could be used in future FTC labeling requirements. 
DOE requests comment on whether DOE should adopt such a provision in 
the final rule in this rulemaking or postpone adoption until FTC has 
had an opportunity to evaluate the ENERGY GUIDE label.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

    The Office of Management and Budget (OMB) has determined that test 
procedure rulemakings do not constitute ``significant regulatory 
actions'' under section 3(f) of Executive Order 12866, Regulatory 
Planning and Review, 58 FR 51735 (Oct. 4, 1993). Accordingly, this 
action was not subject to review under the Executive Order by the 
Office of Information and Regulatory Affairs (OIRA) in the Office of 
Management and Budget.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of an initial regulatory flexibility analysis (IFRA) for 
any rule that by law must be proposed for public comment, unless the 
agency certifies that the rule, if promulgated, will not have a 
significant economic impact on a substantial number of small entities. 
As required by 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 Web site: http://energy.gov/gc/office-general-counsel.
    This proposed rule would prescribe a mathematical conversion that 
would be used to determine compliance with energy conservation 
standards for consumer water heaters and certain commercial water 
heaters. For consumer water heaters and certain commercial water 
heaters, the mathematical conversion would establish a bridge between 
the rated values based on the results under the current test procedures 
and the uniform efficiency descriptor of the new test procedure. 
Furthermore, the conversion factor will ensure that no products which 
currently pass energy conservation standards fail to meet the energy 
conservation standards after the conversion factor has been applied. 
DOE reviewed this proposed rule under the provisions of the Regulatory 
Flexibility Act and the policies and procedures published on February 
19, 2003. 68 FR 7990.
    For the manufacturers of the covered water heater products, the 
Small Business Administration (SBA) has set a size threshold, which 
defines those entities classified as ``small businesses'' for the 
purposes of the statute. DOE used the SBA's small business size 
standards to determine whether any small entities would be subject to 
the requirements of the rule. 65 FR 30836, 30849 (May 15, 2000), as 
amended at 65 FR 53533, 53545 (Sept. 5, 2000) and at 77 FR 49991, 
50008-11 (August 20, 2012) and codified at 13 CFR part 121. The size 
standards are listed by North American Industry Classification System 
(NAICS) code and industry description and are available at http://www.sba.gov/content/table-small-business-size-standards. Consumer water 
heater manufacturing is classified under NAICS code 335228--``Other 
Major Household Appliance Manufacturing.'' The SBA sets a threshold of 
500 employees or less for an entity to be considered as a small 
business. Commercial water heater manufacturing is classified under 
NAICS code 333318--``Other

[[Page 20139]]

Commercial and Service Industry Machinery Manufacturing,'' for which 
SBA sets a size threshold of 1,000 employees or fewer as being 
considered a small business.
    DOE has identified 19 manufacturers of consumer water heaters 
(including manufacturers of products that fall under the expanded 
scope) that can be considered small businesses. DOE identified seven 
manufacturers of ``residential-duty'' commercial water heaters that can 
be considered small businesses. Six of the ``residential-duty'' 
commercial water heater manufacturers also manufacture consumer water 
heaters, so the total number of water heater manufacturers impacted by 
this rule would be 20. DOE's research involved reviewing several 
industry trade association membership directories (e.g., AHRI), product 
databases (e.g., AHRI, CEC, and ENERGY STAR databases), individual 
company Web sites, and marketing research tools (e.g., Hoovers reports) 
to create a list of all domestic small business manufacturers of 
products covered by this rulemaking.
    For the reasons explained below, DOE has concluded that the test 
procedure amendments contained in this proposed rule would not have a 
significant economic impact on any manufacturer, including small 
manufacturers.
    For consumer water heaters that were covered under the old test 
procedure and energy conservation standards, the conversion factor in 
this proposed rule would convert the rated values based on the current 
test procedure to equivalent values based on the new uniform descriptor 
test procedure. Although the energy conservation standards for consumer 
water heaters will be denominated using the uniform descriptor, the 
statute provides that all units that are on the market as of July 13, 
2015, that meet the April 16, 2015 energy factor standard will be 
deemed to meet the converted standards.
    For certain commercial water heaters, defined under the term 
``residential-duty commercial water heater,'' the conversion factor in 
this proposed rule would convert the rated values based on the current 
test procedure to the uniform descriptor which is based on the new test 
procedure. The energy conservation standards for commercial water 
heating equipment will be denominated using the uniform descriptor. The 
statute provides that all units that are on the market as of July 13, 
2015, that meet the thermal efficiency and standby losses standards 
will be deemed to meet the converted standards.
    At the date that compliance is required with the new test 
procedure, all water heating units with residential applications (i.e., 
consumer units and residential-duty commercial units) must meet the 
applicable energy conservation standards. These units will be re-rated 
to the uniform descriptor based on the new test procedure. This 
conversion will not result in any increase in stringency of the energy 
conservation standards. Therefore, no units that are on the market at 
the time of this rulemaking will be made illegal (noncompliant) by this 
action.
    Accordingly, DOE concludes and certifies that this final rule would 
not have a significant economic impact on a substantial number of small 
entities, so DOE has not prepared a regulatory flexibility analysis for 
this rulemaking. DOE will provide its certification and supporting 
statement of factual basis to the Chief Counsel for Advocacy of the SBA 
for review under 5 U.S.C. 605(b).

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of water heaters must certify to DOE that their 
products comply with any applicable energy conservation standards. In 
certifying compliance, manufacturers must test their products according 
to the DOE test procedures for water heaters, 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 consumer and 
commercial water heaters. 76 FR 12422 (March 7, 2011); 79 FR 25486 (May 
5, 2014). 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 30 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.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this proposed rule, DOE proposes conversion factors to convert 
results from existing efficiency and delivery capacity metrics (and 
related energy conservation standard requirements) for consumer and 
certain commercial water heaters to the uniform energy descriptor. DOE 
has determined that this rule falls into a class of actions that are 
categorically excluded from review under the National Environmental 
Policy Act of 1969 (42 U.S.C. 4321 et seq.) and DOE's implementing 
regulations at 10 CFR part 1021. Specifically, this proposed rule would 
amend the existing rule without affecting the amount, quality or 
distribution of energy usage, and, therefore, would not result in any 
environmental impacts. Thus, this rulemaking is covered by Categorical 
Exclusion A5 under 10 CFR part 1021, subpart D, which applies to any 
rulemaking that interprets or amends an existing rule without changing 
the environmental effect of that rule. 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 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 has examined this 
proposed rule and has determined that it would 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 proposed 
rule. States can petition DOE

[[Page 20140]]

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. Regarding the review required by section 3(a), 
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, the proposed 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 proposed regulatory action likely to result 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 them. On March 18, 1997, DOE published 
a statement of policy on its process for intergovernmental consultation 
under UMRA. 62 FR 12820. (This policy is also available at http://energy.gov/gc/office-general-counsel.) DOE examined this proposed 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 by State, local, and Tribal governments, 
in the aggregate, or by the private sector, of $100 million or more in 
any year. Accordingly, no further assessment or analysis is required 
under UMRA.

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 rule would 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

    Pursuant to Executive Order 12630, ``Governmental Actions and 
Interference with Constitutionally Protected Property Rights,'' 53 FR 
8859 (March 18, 1988), DOE has determined that this regulation would 
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 information quality 
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). DOE has reviewed this proposed 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 OIRA 
at OMB, a Statement of Energy Effects for any proposed significant 
energy action. A ``significant energy action'' is defined as any action 
by an agency that promulgates 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 proposed significant energy action, 
the agency must give a detailed statement of any adverse effects on 
energy supply, distribution, or use should the proposal be implemented, 
and of reasonable alternatives to the action and their expected 
benefits on energy supply, distribution, and use.
    This regulatory action, which would develop a conversion factor to 
amend the energy conservation standards for consumer and certain 
commercial water heaters in light of new test procedures is not a 
significant regulatory action under Executive Order 12866 or any 
successor order. Moreover, it would not have a significant adverse 
effect on the supply, distribution, or use of energy, nor has it been 
designated as a significant energy action by the Administrator of OIRA. 
Therefore, it is not a significant energy action, and, accordingly, DOE 
has not prepared a Statement of Energy Effects for this rulemaking.

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 et seq.), DOE must comply with all laws 
applicable to the former Federal Energy Administration, including 
section 32 of the Federal Energy Administration Act of 1974 (Pub. L. 
93-275), as amended by the Federal Energy Administration Authorization 
Act of 1977 (Pub. L. 95-70). (15 U.S.C. 788; FEAA) Section 32 
essentially provides in relevant part

[[Page 20141]]

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.
    This proposed rule to implement conversion factors between the 
existing water heaters test procedure and the amended test procedure 
does not incorporate testing methods contained in commercial standards.

V. Public Participation

A. Submission of Comments

    DOE will accept comments, data, and information regarding this 
proposed rule no later than the date provided in the DATES section at 
the beginning of this proposed rule. Interested parties may submit 
comments, data, and other information using any of the methods 
described in the ADDRESSES section at the beginning of this document.
    Submitting comments via www.regulations.gov. The 
www.regulations.gov Web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment itself or in any documents attached to your 
comment. Any information that you do not want to be publicly viewable 
should not be included in your comment, nor in any document attached to 
your comment. Otherwise, persons viewing comments will see only first 
and last names, organization names, correspondence containing comments, 
and any documents submitted with the comments.
    Do not submit to www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (CBI)). Comments submitted through 
www.regulations.gov cannot be claimed as CBI. Comments received through 
the Web site will waive any CBI claims for the information submitted. 
For information on submitting CBI, see the Confidential Business 
Information section.
    DOE processes submissions made through www.regulations.gov before 
posting. Normally, comments will be posted within a few days of being 
submitted. However, if large volumes of comments are being processed 
simultaneously, your comment may not be viewable for up to several 
weeks. Please keep the comment tracking number that www.regulations.gov 
provides after you have successfully uploaded your comment.
    Submitting comments via email, hand delivery/courier, or mail. 
Comments and documents submitted via email, hand delivery/courier, or 
mail also will be posted to www.regulations.gov. If you do not want 
your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information in a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. If you submit via mail or hand 
delivery/courier, please provide all items on a CD, if feasible, in 
which case it is not necessary to submit printed copies. No 
telefacsimiles (faxes) will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, that are written in English, and that are free of any 
defects or viruses. Documents should not contain special characters or 
any form of encryption and, if possible, they should carry the 
electronic signature of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. Pursuant to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email, postal mail, or hand delivery/courier two well-marked copies: 
one copy of the document marked ``confidential'' including all the 
information believed to be confidential, and one copy of the document 
marked ``non-confidential'' with the information believed to be 
confidential deleted. Submit these documents via email or on a CD, if 
feasible. DOE will make its own determination about the confidential 
status of the information and treat it according to its determination.
    Factors of interest to DOE when evaluating requests to treat 
submitted information as confidential include: (1) A description of the 
items; (2) whether and why such items are customarily treated as 
confidential within the industry; (3) whether the information is 
generally known by or available from other sources; (4) whether the 
information has previously been made available to others without 
obligation concerning its confidentiality; (5) an explanation of the 
competitive injury to the submitting person which would result from 
public disclosure; (6) when such information might lose its 
confidential character due to the passage of time; and (7) why 
disclosure of the information would be contrary to the public interest.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).

B. Issues on Which DOE Seeks Comment

    Although DOE welcomes comments on any aspect of this proposal, DOE 
is particularly interested in receiving comments and views of 
interested parties concerning the following issues:
    1. Has DOE identified all of the water heaters requiring a 
conversion from the old test procedures for consumer and commercial 
water heaters to the new test procedure for the uniform test method for 
measuring the energy consumption of water heaters?
    2. Are the proposed analytical methods appropriate for the 
conversion factor analysis?
    3. Is the proposed regression method appropriate for the conversion 
factor analysis?
    4. How do manufacturers specify whether a water heater is short or 
tall? Is there any criteria that could be applied to compare short and 
tall designs across all manufacturers?
    5. Is the proposed percentage difference method appropriate for the 
derivation of energy conservation

[[Page 20142]]

standards based on the updated test procedure?

VI. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this notice of 
proposed rulemaking.

List of Subjects

10 CFR Part 429

    Confidential business information, Energy conservation, Household 
appliances, Imports, Reporting and recordkeeping requirements.

10 CFR Part 430

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

10 CFR Part 431

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

    Issued in Washington, DC, on March 27, 2015.
Kathleen B. Hogan,
Deputy Assistant Secretary for Energy Efficiency, Energy Efficiency and 
Renewable Energy.

    For the reasons stated in the preamble, DOE is proposing to amend 
parts 429, 430, and 431 of Chapter II, Subchapter D of Title 10, Code 
of Federal Regulations, as set forth below:

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

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

    Authority:  42 U.S.C. 6291-6317.

0
2. Section 429.17 is revised to read as follows:


Sec.  429.17  Water heaters.

    (a) Determination of represented value.
    (1) As of July 13, 2015, manufacturers must determine the 
represented value for each new basic model of water heater by applying 
an AEDM in accordance with 10 CFR 429.70 or by testing for the uniform 
energy factor, in conjunction with the applicable sampling provisions 
as follows:
    (i) If the represented value is determined through testing, the 
general requirements of 10 CFR 429.11 are applicable; and
    (ii) For each basic model selected for testing, a sample of 
sufficient size shall be randomly selected and tested to ensure that--
    (A) Any represented value of the estimated annual operating cost or 
other measure of energy consumption of a basic model for which 
consumers would favor lower values shall be greater than or equal to 
the higher of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP14AP15.019
    

and, x is the sample mean; n is the number of samples; and 
xi is the ith sample;
    Or,
    (2) The upper 95-percent confidence limit (UCL) of the true mean 
divided by 1.10, where:
[GRAPHIC] [TIFF OMITTED] TP14AP15.020

    And xis the sample mean; s is the sample standard deviation; n is 
the number of samples; and t0.95 is the t statistic for a 
95-percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).

and
    (B) Any represented value of the uniform energy factor, energy 
factor, or other measure of energy consumption of a basic model for 
which consumers would favor higher values shall be less than or equal 
to the lower of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP14AP15.021
    

and, x is the sample mean; n is the number of samples; and 
xi is the ith sample;

Or,
    (2) The lower 95-percent confidence limit (LCL) of the true mean 
divided by 0.90, where:
[GRAPHIC] [TIFF OMITTED] TP14AP15.022


And xis the sample mean; s is the sample standard deviation; n is the 
number of samples; and t0.95 is the t statistic for a 95-
percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (2) For basic models initially certified before July 13, 2015 
(using either the energy factor test procedure contained in Appendix E 
to Subpart B of 10 CFR part 430 of the January 1, 2015 edition of the 
Code of Federal Regulations or the thermal efficiency and standby loss 
test procedures contained in 10 CFR 431.106 of the January 1, 2015 
edition of the Code of Federal Regulations, in conjunction with 
applicable sampling provisions), manufacturers must:
    (i) Conduct testing for the uniform energy factor, in conjunction 
with the applicable sampling provisions of this paragraph;
    (ii) Apply an AEDM in accordance with 10 CFR 429.70; or
    (iii) Calculate the uniform energy factor by applying the following 
mathematical conversion factors to the previously certified value of 
energy factor as follows. Representations of uniform energy factor 
based on a calculation using this mathematical conversion factor must 
be equal to the uniform energy factor value resulting from the 
application of the appropriate equation below.
    (A) The applicable mathematical conversion factors are as follows:

----------------------------------------------------------------------------------------------------------------
          Product class            Distinguishing criteria                   Conversion factor *
----------------------------------------------------------------------------------------------------------------
Consumer Gas-fired Water Heater.  Non-Condensing, Standard  New FHR = 1.0085 * FHREx
                                   NOX.                     UEF = 0.4736 + 0.2726 * UEFWHAM
                                  Non-Condensing, Low NOX.  New FHR = 4.6894 = 0.9112 * FHREx
                                                            UEF = -0.0126 + 0.9966 * UEFWHAM
                                  Non-Condensing, Ultra-    New FHR = 2.9267 + 0.8882 * FHREx
                                   Low NOX.                 UEF = 0.2673 + 0.5811 * UEFWHAM
                                  Condensing..............  New FHR = -0.7072 + 0.9724 * FHREx
                                                            UEF = 0.0409 + 0.9164 * UEFWHAM
Consumer Oil-fired Water Heater.  N/A.....................  New FHR = 1.1018 * FHREx
                                                            UEF = -0.0945 + 1.1185 * UEFWHAM
Consumer Electric Water Heater..  Electric Resistance.....  New FHR = 11.9239 + 0.789 * FHREx
                                                            UEF = 0.1227 + 0.8673 * UEFWHAM

[[Page 20143]]

 
                                  Heat Pump...............  New FHR = -2.3440 + 0.9856 * FHREx
                                                            UEF = -1.1235 + 1.5485 * EF
Tabletop Water Heater...........  N/A.....................  New FHR = 11.9239 + 0.7879 * FHREx
                                                            UEF = 0.1227 + 0.8673 * UEFWHAM
Instantaneous Gas-fired Water     N/A.....................  New Max GPM = 1.1467 * Max GPMEx
 Heater.                                                    UEF = 0.0783 + 0.9052 * UEFmodel
Instantaneous Electric Water      N/A.....................  New Max GPM = 1.1467 * Max GPMEx
 Heater.                                                    UEF = 1.0079 * UEFmodel
Residential-Duty Commercial Gas-  N/A.....................  New FHR = 39.8144 + 1.0226 * Q
 fired Water Heater.                                        UEF = 0.1413 + 0.7300 * UEFWHAM
Residential-Duty Commercial Oil-  N/A.....................  New FHR = 39.8144 + 1.0226 * Q
 fired Water Heater.                                        UEF = 0.1413 + 0.7300 * UEFWHAM
----------------------------------------------------------------------------------------------------------------
 *FHREX = current first-hour rating.
Max GPMEX = current max GPM rating.
Q = nameplate input rate, in kBtu/hr.
UEFWHAM = the UEF predicted based on either the WHAM equation (for consumer storage water heaters) or the
  modified WHAM (for residential-duty commercial water heaters, as defined in the sub-paragraphs below).
UEFmodel = the UEF predicted based on the analytical model developed by DOE (for consumer instantaneous water
  heaters).

    (B) Calculate UEFWHAM (for consumer storage water 
heaters and residential-duty commercial storage water heaters) and 
UEFmodel (for consumer instantaneous water heaters) as 
follows:
    (1) For consumer storage water heaters:

    [GRAPHIC] [TIFF OMITTED] TP14AP15.023
    


Where a, b, c, and d are coefficients based on the applicable draw 
pattern as specified in the table below; EF is the current energy 
factor rating; [eta]r is the current recovery efficiency 
rating in decimal form; and P is the input rating in Btu/h.

----------------------------------------------------------------------------------------------------------------
            Draw pattern                      a                  b                  c                  d
----------------------------------------------------------------------------------------------------------------
Very Small..........................           56095146        12884892499            8930623        15125743368
Low.................................           56095146        48962591496           33936368        57477824799
Medium..............................           56095146        70866908744           49118427        83191588525
High................................           56095146       108233096990           75017235       127056244293
----------------------------------------------------------------------------------------------------------------

    (2) For consumer instantaneous water heaters:

    [GRAPHIC] [TIFF OMITTED] TP14AP15.024
    


Where [eta]r is the current recovery efficiency rating expressed in 
decimal form and A and B are coefficients dependent upon the applicable 
draw pattern as specified in the table below.

------------------------------------------------------------------------
              Draw pattern                      A                B
------------------------------------------------------------------------
Very Small.............................           5514.2           170.2
Low....................................          20954             262.4
Medium.................................          30328             290.9
High...................................          46319             294.0
------------------------------------------------------------------------

    (3) For residential-duty commercial water heaters:

    [GRAPHIC] [TIFF OMITTED] TP14AP15.025
    


Where, Et is the existing thermal efficiency rating; SL is 
the existing standby loss rating in Btu/h; and C1 is a 
coefficient as specified in the table below based on the applicable 
draw pattern.

------------------------------------------------------------------------
                      Draw pattern                              C1
------------------------------------------------------------------------
Very Small..............................................    3.575 x 10-3
Low.....................................................    9.408 x 10-4
Medium..................................................    6.500 x 10-4
High....................................................    4.256 x 10-4
------------------------------------------------------------------------

    (3) Any represented value of the rated storage volume must be equal 
to the mean of the measured storage volumes of all the units within the 
sample.
    (4) Any represented value of first-hour rating or maximum gallons 
per minute (GPM) must be equal to the mean of the measured first-hour 
ratings or measured maximum GPM ratings, respectively, of all the units 
within the sample.
    (b) Certification reports. (1) The requirements of 10 CFR 429.12 
are applicable to water heaters; and
    (2) Pursuant to 10 CFR 429.12(b)(13), a certification report shall 
include the following public product-specific information:
    (i) For storage-type water heater basic models tested for energy 
factor and rated pursuant to 10 CFR 429.17(a)(2)(iii): Energy factor, 
uniform energy factor, rated storage volume (gal), first-hour rating 
(gal), and recovery efficiency (percent);
    (ii) For storage-type water heater basic models tested for uniform 
energy factor and rated pursuant to 10 CFR 429.17(a)(1) or 10 CFR 
429.17(a)(2)(i) through (ii): Uniform energy factor, rated storage 
volume in gallons (gal), first-hour rating (gal), and recovery 
efficiency (percent);
    (iii) For instantaneous-type water heater basic models tested for 
energy factor and rated pursuant to 10 CFR 429.17(a)(2)(iii): Energy 
factor, uniform energy factor, rated storage volume (gal), maximum 
gallons per minute, and recovery efficiency (percent); and

[[Page 20144]]

    (iv) For instantaneous-type water heater basic models tested for 
uniform energy factor and rated pursuant to 10 CFR 429.17(a)(1) or 10 
CFR 429.17(a)(2)(i) through (ii): Uniform energy factor, rated storage 
volume (gal), maximum gallons per minute, and recovery efficiency 
(percent).
0
3. Section 429.17 is further revised, effective [date one year after 
publication of final rule], to read as follows:


Sec.  429.17  Water heaters.

    (a) Determination of represented value. (1) Manufacturers must 
determine the represented value for each water heater by applying an 
AEDM in accordance with 10 CFR 429.70 or by testing for the uniform 
energy factor, in conjunction with the applicable sampling provisions 
as follows:
    (i) If the represented value is determined through testing, the 
general requirements of 10 CFR 429.11 are applicable; and
    (ii) For each basic model selected for testing, a sample of 
sufficient size shall be randomly selected and tested to ensure that--
    (A) Any represented value of the estimated annual operating cost or 
other measure of energy consumption of a basic model for which 
consumers would favor lower values shall be greater than or equal to 
the higher of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP14AP15.026
    

and, x is the sample mean; n is the number of samples; and 
xi is the ith sample;
    Or,
    (2) The upper 95-percent confidence limit (UCL) of the true mean 
divided by 1.10, where:
[GRAPHIC] [TIFF OMITTED] TP14AP15.027


And, x is the sample mean; s is the sample standard deviation; n is the 
number of samples; and t0.95 is the t statistic for a 95-
percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    and
    (B) Any represented value of the uniform energy factor, energy 
factor, or other measure of energy consumption of a basic model for 
which consumers would favor higher values shall be less than or equal 
to the lower of:
    (1) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP14AP15.028
    

and, x is the sample mean; n is the number of samples; and 
xi is the ith sample;
    Or,
    (2) The lower 95-percent confidence limit (LCL) of the true mean 
divided by 0.90, where:
[GRAPHIC] [TIFF OMITTED] TP14AP15.029


And x is the sample mean; s is the sample standard deviation; n is the 
number of samples; and t0.95 is the t statistic for a 95-
percent one-tailed confidence interval with n-1 degrees of freedom 
(from Appendix A).
    (2) Any represented value of the rated storage volume must be equal 
to the mean of the measured storage volumes of all the units within the 
sample.
    (3) Any represented value of first-hour rating or maximum gallons 
per minute (GPM) must be equal to the mean of the measured first-hour 
ratings or measured maximum GPM ratings, respectively, of all the units 
within the sample.
    (b) Certification reports. (1) The requirements of 10 CFR 429.12 
are applicable to water heaters; and
    (2) Pursuant to 10 CFR 429.12(b)(13), a certification report shall 
include the following public product-specific information:
    (i) For storage-type water heater basic models: Uniform energy 
factor, rated storage volume in gallons (gal), first-hour rating (gal), 
and recovery efficiency (percent);
    (ii) For instantaneous-type water heater basic models: Uniform 
energy factor, rated storage volume (gal), maximum gallons per minute, 
and recovery efficiency (percent); and
    (iii) For instantaneous-type water heater basic models: Uniform 
energy factor, rated storage volume (gal), maximum gallons per minute, 
and recovery efficiency (percent).
0
4. Section 429.44 is amended by:
0
a. Revising paragraph (a) introductory text;
0
b. Adding new paragraphs (c)(2)(vii) and (viii);
    The revisions and additions read as follows:


Sec.  429.44  Commercial water heating equipment.

    (a) For residential-duty commercial water heaters, determine 
representations as provided in 10 CFR 429.17(a).
* * * * *
    (c) * * *
    (2) * * *
    (vii) Residential-duty commercial gas-fired and oil-fired storage 
water heaters tested for thermal efficiency and standby loss and rated 
pursuant to 10 CFR 429.17(a)(2)(iii): Thermal efficiency in percent 
(%), maximum standby loss in British thermal units per hour (Btu/h), 
uniform energy factor, rated storage volume (gal), and the nameplate 
input rate in British thermal units per hour (Btu/h).
    (viii) Residential-duty commercial gas-fired and oil-fired storage 
water heaters tested for uniform energy factor and rated pursuant to 10 
CFR 429.17(a)(1) or 10 CFR 429.17(a)(2)(i) through (ii): Uniform energy 
factor, rated storage volume (gal), first-hour rating (gal), and 
recovery efficiency (percent).
* * * * *
0
5. Section 429.44 is further revised, effective [date one year after 
publication of final rule], to read as follows:
0
a. Removing paragraph (c)(2)(vii);
0
b. Redesignating paragraph (c)(2)(viii) as (c)(2)(vii); and
0
c. Revising newly redesignated paragraph (c)(2)(vii) to read as 
follows:


Sec.  429.44  Commercial water heating equipment.

* * * * *
    (c) * * *
    (2) * * *
    (vii) Residential-duty commercial gas-fired and oil-fired storage 
water heaters: Uniform energy factor, rated storage volume (gal), 
first-hour rating (gal), and recovery efficiency (percent).
* * * * *

PART 430--ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS

0
6. The authority citation for part 430 continues to read as follows:

    Authority:  42 U.S.C. 6291-6309; 28 U.S.C. 2461 note.

0
7. Section 430.23 is amended by revising paragraph (e) to read as 
follows:


Sec.  430.23  Test procedures for the measurement of energy and water 
consumption.

* * * * *
    (e) Water Heaters. (1) For water heaters tested using energy 
factor:
    (i) The estimated annual operating cost for water heaters tested in 
terms of energy factor shall be--
    (A) For a gas or oil water heater, the product of the annual energy 
consumption, determined according to section 6.1.8 or 6.2.5 of appendix 
E to subpart B of 10 CFR part 430 of the January 1, 2015 edition of the 
Code of Federal Regulations, times the representative average unit cost 
of gas or oil, as appropriate, in dollars per Btu as provided by the 
Secretary. The resulting product shall be rounded off to the nearest 
dollar per year.

[[Page 20145]]

    (B) For an electric water heater, the product of the annual energy 
consumption, determined according to section 6.1.8 or 6.2.5 of appendix 
E to subpart B to 10 CFR part 430 of the January 1, 2015 edition of the 
Code of Federal Regulations, times the representative average unit cost 
of electricity in dollars per kilowatt-hour as provided by the 
Secretary, divided by 3412 Btu per kilowatt-hour. The resulting 
quotient shall be rounded off to the nearest dollar per year.
    (ii) For an individual test, the tested energy factor for a water 
heater shall be determined by section 6.1.7 or 6.2.4 of appendix E to 
subpart B of 10 CFR part 430 of the January 1, 2015 edition of the Code 
of Federal Regulations, rounded off to the nearest 0.01.
    (2) For water heaters tested using uniform energy factor:
    (i) The estimated annual operating cost shall be:
    (A) For a gas or oil water heater, the sum of: The product of the 
annual gas or oil energy consumption, determined according to section 
6.1.10 or 6.2.7 of appendix E of this subpart, times the representative 
average unit cost of gas or oil, as appropriate, in dollars per Btu as 
provided by the Secretary; plus the product of the annual electric 
energy consumption, determined according to section 6.1.9 or 6.2.6 of 
appendix E of this subpart, times the representative average unit cost 
of electricity in dollars per kilowatt-hour as provided by the 
Secretary. The resulting sum shall be rounded off to the nearest dollar 
per year.
    (B) For an electric water heater, the product of the annual energy 
consumption, determined according to section 6.1.9 or 6.2.6 of appendix 
E of this subpart, times the representative average unit cost of 
electricity in dollars per kilowatt-hour as provided by the Secretary. 
The resulting product shall be rounded off to the nearest dollar per 
year.
    (ii) For an individual test, the tested uniform energy factor for a 
water heater shall be determined by section 6.1.7 or 6.2.4 of appendix 
E of this subpart, rounded to the nearest 0.01.
* * * * *
0
8. Section 430.32 is amended by revising paragraph (d) to read as 
follows:


Sec.  430.32  Energy and water conservation standards and their 
compliance dates.

* * * * *
    (d) Water heaters. The energy factor of each basic model of water 
heater shall not be less than the following:

----------------------------------------------------------------------------------------------------------------
                                  Rated storage                                Uniform energy factor as of July
         Product class                volume              Draw pattern                     13, 2015*
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage.............  >= 20 gal and <=   Very Small...............  0.3263-(0.0019 x Vr)
                                 55 gal.
                                                   Low......................  0.5891-(0.0019 x Vr)
                                                   Medium...................  0.6326-(0.0013 x Vr)
                                                   High.....................  0.7128-(0.0025 x Vr)
                                < 55 gal and <=    Very Small...............  0.5352-(0.0007 x Vr)
                                 100 gal.
                                                   Low......................  0.7375-(0.0009 x Vr)
                                                   Medium...................  0.7704-(0.0010 x Vr)
                                                   High.....................  0.7980-(0.0010 x Vr)
Oil-fired Storage.............  <= 50 gal........  Very Small...............  0.2267-(0.0014 x Vr)
                                                   Low......................  0.4867-(0.0006 x Vr)
                                                   Medium...................  0.6016-(0.0012 x Vr)
                                                   High.....................  0.6529-(0.0005 x Vr)
Electric Storage..............  >= 20 gal and <=   Very Small...............  0.8268-(0.0002 x Vr)
                                 55 gal.
                                                   Low......................  0.9393-(0.0004 x Vr)
                                                   Medium...................  0.9683-(0.0007 x Vr)
                                                   High.....................  0.9656-(0.0004 x Vr)
                                < 55 gal and <=    Very Small...............  1.2701-(0.0011 x Vr)
                                 120 gal.
                                                   Low......................  1.9137-(0.0011 x Vr)
                                                   Medium...................  2.0626-(0.0011 x Vr)
                                                   High.....................  2.1858-(0.0011 x Vr)
Tabletop Storage..............  >= 20 gal and <=   Very Small...............  0.6808-(0.0022 x Vr)
                                 100 gal.
                                                   Low......................  0.8770-(0.0012 x Vr)
                                                   Medium...................  0.9063-(0.0009 x Vr)
                                                   High.....................  0.9302-(0.0006 x Vr)
Gas-fired Instantaneous.......  < 2 gal..........  All......................  0.8036-(0.0019 x Vr)
Electric Instantaneous........  < 2 gal..........  All......................  0.9192-(0.0013 x Vr)
----------------------------------------------------------------------------------------------------------------
*Vr is rated storage volume.

* * * * *

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

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

    Authority:  42 U.S.C. 6291-6317.

0
10. In Sec.  431.106 revise paragraph (b) to read as follows:


Sec.  431.106  Uniform test method for the measurement of energy 
efficiency of commercial water heaters and hot water supply boilers 
(other than commercial heat pump water heaters).

* * * * *
    (b) Testing and Calculations. Determine the energy efficiency of 
each class of equipment by conducting the applicable test procedure(s), 
set forth in the three rightmost columns of the following table:

[[Page 20146]]



Table 1 to Sec.   431.106--Test Procedures for Commercial Water Heaters and Hot Water Supply Boilers (Other Than
                                       Commercial Heat Pump Water Heaters)
----------------------------------------------------------------------------------------------------------------
                                                                         Test procedure
                                 Energy efficiency                        required for     With these additional
         Equipment type              descriptor       Test procedure   compliance on and       stipulations
                                                                             after
----------------------------------------------------------------------------------------------------------------
Residential-Duty Commercial      Uniform Energy     10 CFR Part 430,   July 13, 2015....
 Water Heater.                    Factor.            Subpart B,
                                                     Appendix E.
Gas-fired Storage and            Thermal            Use test set-up,   May 13, 2013.....  A. For all products,
 Instantaneous Water Heaters      Efficiency.        equipment, and                        the duration of the
 and Hot Water Supply Boilers.                       procedures in                         standby loss test
                                                     subsection                            shall be until
                                                     labeled ``Method                      whichever of the
                                                     of Test'' of                          following occurs
                                                     ANSI Z21.10.3-                        first after you begin
                                                     2011**, Exhibit                       to measure the fuel
                                                     G1.                                   and/or electric
                                                                                           consumption: (1) The
                                                                                           first cut-out after
                                                                                           24 hours or (2) 48
                                                                                           hours, if the water
                                                                                           heater is not in the
                                                                                           heating mode at that
                                                                                           time.
                                 Standby Loss.....  Use test set-up,   May 13, 2013.....  B. For oil and gas
                                                     equipment, and                        products, the standby
                                                     procedures in                         loss in Btu per hour
                                                     subsection                            must be calculated as
                                                     labeled ``Method                      follows: SL (Btu per
                                                     of Test'' of                          hour) = S (% per
                                                     ANSI Z21.10.3-                        hour) x 8.25 (Btu/gal-
                                                     2011**, Exhibit                       F) x Measured Volume
                                                     G2.                                   (gal) x 70 (degrees
                                                                                           F).
Oil-fired Storage and            Thermal            ANSI Z21.10.3-     May 13, 2013.....  C. For oil-fired
 Instantaneous Water Heaters      Efficiency.        2011**, Exhibit                       products, apply the
 and Hot Water Supply Boilers.                       G1.                                   following in
                                                                                           conducting the
                                                                                           thermal efficiency
                                                                                           and standby loss
                                                                                           tests: (1) Venting
                                                                                           Requirements--Connect
                                                                                           a vertical length of
                                                                                           flue pipe to the flue
                                                                                           gas outlet of
                                                                                           sufficient height so
                                                                                           as to meet the
                                                                                           minimum draft
                                                                                           specified by the
                                                                                           manufacturer. (2) Oil
                                                                                           Supply--Adjust the
                                                                                           burner rate so that:
                                                                                           (a) The hourly Btu
                                                                                           input rate lies
                                                                                           within 2
                                                                                           percent of the
                                                                                           manufacturer's
                                                                                           specified input rate,
                                                                                           (b) the CO2 reading
                                                                                           shows the value
                                                                                           specified by the
                                                                                           manufacturer, (c)
                                                                                           smoke in the flue
                                                                                           does not exceed No. 1
                                                                                           smoke as measured by
                                                                                           the procedure in ASTM-
                                                                                           D2156-80 (reference
                                                                                           for guidance only,
                                                                                           see Sec.   431.104),
                                                                                           and (d) fuel pump
                                                                                           pressure lies within
                                                                                           10
                                                                                           percent of
                                                                                           manufacturer's
                                                                                           specifications.
                                 Standby Loss.....  Use test set-up,   May 13, 2013.....
                                                     equipment, and
                                                     procedures in
                                                     subsection
                                                     labeled ``Method
                                                     of Test'' of
                                                     ANSI Z21.10.3-
                                                     2011**, Exhibit
                                                     G2.
Electric Storage and             Standby Loss.....  Use test set-up,   May 13, 2013.....  D. For electric
 Instantaneous Water Heaters.                        equipment, and                        products, apply the
                                                     procedures in                         following in
                                                     subsection                            conducting the
                                                     labeled ``Method                      standby loss test:
                                                     of Test'' of                          (1) Assume that the
                                                     ANSI Z21.10.3-                        thermal efficiency
                                                     2011**, Exhibit                       (Et) of electric
                                                     G2.                                   water heaters with
                                                                                           immersed heating
                                                                                           elements is 98
                                                                                           percent. (2) Maintain
                                                                                           the electrical supply
                                                                                           voltage to within
                                                                                           5 percent
                                                                                           of the center of the
                                                                                           voltage range
                                                                                           specified on the
                                                                                           water heater
                                                                                           nameplate. (3) If the
                                                                                           set up includes
                                                                                           multiple adjustable
                                                                                           thermostats, set the
                                                                                           highest one first to
                                                                                           yield a maximum water
                                                                                           temperature in the
                                                                                           specified range as
                                                                                           measured by the
                                                                                           topmost tank
                                                                                           thermocouple. Then
                                                                                           set the lower
                                                                                           thermostat(s) to
                                                                                           yield a maximum mean
                                                                                           tank temperature
                                                                                           within the specified
                                                                                           range.
                                                                                          E. Install water-tube
                                                                                           water heaters as
                                                                                           shown in Figure 2,
                                                                                           ``Arrangement for
                                                                                           Testing Water-tube
                                                                                           Type Instantaneous
                                                                                           and Circulating Water
                                                                                           Heaters.''
----------------------------------------------------------------------------------------------------------------
** Incorporated by reference, see Sec.   431.105.


[[Page 20147]]

0
11. Section 431.110 is revised to read as follows:


Sec.  431.110  Energy conservation standards and their effective dates.

    Each commercial storage water heater, instantaneous water heater, 
unfired hot water storage tank and hot water supply boiler \1\ (except 
for residential-duty commercial water heaters) must meet the applicable 
energy conservation standard level(s) as follows:
---------------------------------------------------------------------------

    \1\Any packaged boiler that provides service water, that meets 
the definition of ``commercial packaged boiler'' in subpart E of 
this part, but does not meet the definition of ``hot water supply 
boiler'' in subpart G, must meet the requirements that apply to it 
under subpart E.

----------------------------------------------------------------------------------------------------------------
                                                                   Energy conservation standard \a\ (products
                                                                 manufactured on and after October 29, 2003) \b\
               Product                           Size          -------------------------------------------------
                                                                    Minimum thermal        Maximum standby loss
                                                                       efficiency                  \c\
----------------------------------------------------------------------------------------------------------------
Electric storage water heaters.......  All....................  N/A....................  0.30 + 27/Vm (%/hr)
Gas-fired storage water heaters......  <=155,000 Btu/hr.......  80%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
                                        >155,000 Btu/hr.......  80%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
Oil-fired storage water heaters......  <=155,000 Btu/hr.......  78%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
                                        >155,000 Btu/hr.......  78%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
Gas-fired instantaneous water heaters  <10 gal................  80%....................  N/A
 and hot water supply boilers.
                                        >=10 gal..............  80%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
Oil-fired instantaneous water heaters  <10 gal................  80%....................  N/A
 and hot water supply boilers.
                                        >=10 gal..............  78%....................  Q/800 + 110(Vr)\1/2\
                                                                                          (Btu/hr)
----------------------------------------------------------------------------------------------------------------
               Product                           Size                      Minimum thermal insulation
----------------------------------------------------------------------------------------------------------------
Unfired hot water storage tank.......  All....................  R-12.5.................
----------------------------------------------------------------------------------------------------------------
\a\Vm is the measured storage volume and Vr is the rated volume, both in gallons. Q is the nameplate input rate
  in Btu/hr.
\b\ For hot water supply boilers with a capacity of less than 10 gallons: (1) the standards are mandatory for
  products manufactured on and after October 21, 2005, and (2) products manufactured prior to that date, and on
  or after October 23, 2003, must meet either the standards listed in this table or the applicable standards in
  subpart E of this part for a ``commercial packaged boiler.''
\c\ Water heaters and hot water supply boilers having more than 140 gallons of storage capacity need not meet
  the standby loss requirement if (1) the tank surface area is thermally insulated to R-12.5 or more, (2) a
  standing pilot light is not used and (3) for gas or oil-fired storage water heaters, they have a fire damper
  or fan assisted combustion.

    Each residential-duty commercial water heater, as defined in 10 CFR 
431.102, must meet the applicable energy conservation standard level as 
follows:

----------------------------------------------------------------------------------------------------------------
            Product class                        Draw pattern                    Uniform energy factor*
----------------------------------------------------------------------------------------------------------------
Gas-fired Storage....................  Very Small.....................  0.3261-(0.0006 x Vr)
                                       Low............................  0.5219-(0.0008 x Vr)
                                       Medium.........................  0.5585-(0.0006 x Vr)
                                       High...........................  0.6044-(0.0005 x Vr)
Oil-fired Storage....................  Very Small.....................  0.3206-(0.0006 x Vr)
                                       Low............................  0.5577-(0.0019 x Vr)
                                       Medium.........................  0.6027-(0.0019 x Vr)
                                       High...........................  0.5446-(0.0018 x Vr)
----------------------------------------------------------------------------------------------------------------
* Vr is the rated storage volume.

[FR Doc. 2015-07932 Filed 4-13-15; 8:45 am]
 BILLING CODE 6450-01-P