Vol. 79 Friday, 

No. 133 July 11, 2014 

Part IV 

Department of Energy 

10 CFR Parts 429, 430, and 431 

Energy Conservation Program for Consumer Products and Certain 

Commercial and Industrial Equipment: Test Procedures for Residential and 

Commercial Water Heaters; Final Rule 


tkelley on DSK3SPTVN1PROD with RULES2
40542 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

1For editorial reasons, upon codification in the 

U.S. Code, Part B was redesignated as Part A. 

2All 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). 

3For editorial reasons, upon codification in the 

U.S. Code, Part C was redesignated Part A–1. 

DEPARTMENT OF ENERGY 

10 CFR Parts 429, 430, and 431 

[Docket No. EERE–2011–BT–TP–0042] 

RIN 1904–AC53 

Energy Conservation Program for 

Consumer Products and Certain 

Commercial and Industrial Equipment: 

Test Procedures for Residential and 

Commercial Water Heaters 

AGENCY: Office of Energy Efficiency and 

Renewable Energy, Department of 

Energy. 

ACTION: Final rule. 

SUMMARY: On November 4, 2013, the 

U.S. Department of Energy (DOE) issued 

a notice of proposed rulemaking (NOPR) 

to amend its test procedures established 

under the Energy Policy and 

Conservation Act for residential water 

heaters and certain commercial water 

heaters, which serves as the basis for 

today’s action. This rulemaking fulfills 

DOE’s statutory obligation for 

residential and certain commercial 

water heaters to review its test 

procedure for covered products and 

equipment at least once every seven 

years. In addition, this rulemaking 

satisfies DOE’s statutory obligation to 

develop a uniform efficiency descriptor 

for residential and commercial water 

heaters. The test method applies the 

same efficiency descriptor to all 

residential and certain commercial 

water heaters, and extends coverage to 

eliminate certain gaps in the current 

residential test procedure, updates the 

simulated-use-test draw pattern, and 

updates the outlet water temperature 

requirement. 

DATES: The effective date of this rule is 

July 13, 2015. Compliance will be 

mandatory starting one year after the 

publication in the Federal Register of a 

mathematical conversion factor to 

convert from the existing efficiency 

ratings to efficiency ratings under the 

test procedure adopted by this final 

rule, or December 31, 2015, whichever 

is later. 

The incorporation by reference of 

certain publications listed in this rule is 

approved by the Director of the Federal 

Register as of July 13, 2015. Other 

publications referenced were approved 

on March 23, 2009, and May 16, 2012. 

ADDRESSES: The docket for this 

rulemaking is available for review at 

www.regulations.gov, including Federal 

Register notices, public meeting 

attendee lists and transcripts, 

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 on the 

www.regulations.gov Web page can be 

found at: http://www.regulations.gov/

#!docketDetail;D=EERE-2011-BT-TP0042. The www.regulations.gov Web 

page contains simple instructions on 

how to access all documents, including 

public comments, in the docket. 

For further information on how to 

review the docket, contact Ms. Brenda 

Edwards at (202) 586–2945 or by email: 

Brenda.Edwards@ee.doe.gov. 

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: 

Ashley.Armstrong@ee.doe.gov. 

Mr. Eric Stas, U.S. Department of 

Energy, Office of the General Counsel, 

GC–71, 1000 Independence Avenue 

SW., Washington, DC 20585–0121. 

Telephone: (202) 586–9507. Email: 

Eric.Stas@hq.doe.gov. 

SUPPLEMENTARY INFORMATION: This final 

rule incorporates by reference the 

following industry standards into 

subpart B of 10 CFR part 430: 

ASTM D2156–09, (‘‘ASTM D2156’’), 

Standard Test Method for Smoke 

Density in Flue Gases from Burning 

Distillate Fuels. 

Copies of ASTM D2156–09 can be 

obtained from the American Society for 

Testing and Materials International, 100 

Barr Harbor Drive, P.O. Box C700, West 

Conshohocken, PA 19428–2959, or go to 

http://www.astm.org. 

Table of Contents 

I. Authority and Background 

II. Summary of the Final Rule 

III. Discussion 

A. Scope 

1. Coverage Range of Uniform Metric and 

Test Procedure 

2. Storage Capacity Limits 

3. Input Capacity Limits 

4. Electric Instantaneous Water Heaters, 

Gas-Fired Heat Pump Water Heaters, and 

Oil-Fired Instantaneous Water Heaters 

B. Uniform Efficiency Descriptor 

Nomenclature 

C. Draw Pattern 

D. Instrumentation 

E. Test Conditions 

1. Outlet Water Temperature 

2. Ambient Temperature and Relative 

Humidity 

3. Laboratory Airflow 

F. Storage Tank Pre-Conditioning 

G. Operational Mode Selection 

H. Annual Energy Consumption 

Calculation 

I. Conversion of Existing Energy Factor 

Ratings 

J. Full Fuel Cycle 

K. Certification, Compliance, and 

Enforcement IssuesC 

1. Storage Volume Requirements 

2. First-Hour Rating and Maximum GPM 

Requirements 

3. Ratings for Untested Models 

L. Reference Standards 

M. Compliance With Other EPCA 

Requirements 

N. Other 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 

L. Review Under Section 32 of the Federal 

Energy Administration Act of 1974 

M. Congressional Notification 

V. Approval of the Office of the Secretary 

I. Authority and Background 

Title III, Part B1 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 

residential water heaters, one subject of 

this rulemaking. (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)) 

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 


tkelley on DSK3SPTVN1PROD with RULES2
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40543 

4On May 16, 2012, DOE published a final rule in 

the Federal Register amending the test procedures 

for commercial water heaters. 77 FR 28928. 

5For more information, please visit DOE’s Web 

site at: http://www1.eere.energy.gov/buildings/

appliance_standards/residential/waterheaters.html. 

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 pursuant to 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 requirements to determine 

whether the products comply with any 

relevant standards promulgated under 

EPCA. (42 U.S.C. 6295(s)) 

Under 42 U.S.C. 6293, EPCA sets forth 

the criteria and procedures that DOE 

must follow when prescribing or 

amending test procedures for residential 

water heaters. EPCA provides, in 

relevant part, that any test procedures 

prescribed or amended under this 

section must be reasonably designed to 

produce test results which measure 

energy efficiency, energy use, or 

estimated annual operating cost of a 

covered product during a representative 

average use cycle or period of use, and 

must not be unduly burdensome to 

conduct. (42 U.S.C. 6293(b)(3)) In 

addition, if DOE determines that a test 

procedure amendment is warranted, it 

must publish proposed test procedures 

and offer the public an opportunity to 

present oral and written comments on 

them. (42 U.S.C. 6293(b)(2)) 

For commercial water heaters, EPCA 

requires that if the test procedure 

referenced in the American Society of 

Heating, Refrigerating, and AirConditioning Engineers (ASHRAE) 

Standard 90.1, ‘‘Energy Standard for 

Buildings Except Low-Rise Residential 

Buildings,’’ is updated, DOE must 

amend its test procedure to be 

consistent with the updated test 

procedure unless DOE determines by 

rule published in the Federal Register 

and supported by clear and convincing 

evidence that the amended test 

procedure is not reasonably designed to 

produce test results which reflect the 

energy efficiency, energy use, or 

estimated operating costs of that type of 

ASHRAE equipment during a 

representative average use cycle. In 

addition, DOE must determine that the 

amended test procedure is not unduly 

burdensome to conduct. (42 U.S.C. 

6314(a)(2) and (4)) 

In any rulemaking to amend a test 

procedure, DOE must determine to what 

extent, if any, the proposed test 

procedure would alter the product’s 

measured energy efficiency. (42 U.S.C. 

6293(e)(1)) If DOE determines that the 

amended test procedure would alter the 

measured efficiency of a covered 

product, DOE must amend the 

applicable energy conservation standard 

accordingly. (42 U.S.C. 6293(e)(2)) 

Further, the Energy Independence and 

Security Act of 2007 (EISA 2007) 

amended EPCA to require that DOE 

must review test procedures for all 

covered products at least once every 

seven years and either amend test 

procedures (if the Secretary determines 

that amended test procedures would 

more accurately or fully comply with 

the requirements of 42 U.S.C. 6293(b)(3) 

for residential products or 42 U.S.C. 

6314(a)(2)–(3) for commercial 

equipment) or publish notice in the 

Federal Register of any determination 

not to amend a test procedure. (42 

U.S.C. 6293(b)(1)(A); 42 U.S.C. 

6314(a)(1)(A)) Under this requirement, 

DOE must review the test procedures for 

residential water heaters not later than 

December 19, 2014 (seven years after the 

enactment of EISA 2007), and DOE must 

review the test procedures for 

commercial water heaters not later than 

May 16, 2019 (seven years after the last 

final rule for commercial water heater 

test procedures 4). The final rule 

resulting from this rulemaking will 

satisfy the requirement to review the 

test procedures for residential and 

certain commercial water heaters every 

seven years. 

DOE’s test procedure for residential 

water heaters is found in the Code of 

Federal Regulations (CFR) at 10 CFR 

430.23(e) and 10 CFR part 430, subpart 

B, appendix E. The test procedure 

includes provisions for determining the 

energy efficiency (energy factor (EF)), as 

well as the annual energy consumption 

of these products. DOE’s test procedure 

for commercial water heaters is found at 

10 CFR 431.106. That test procedure 

incorporates by reference American 

National Standards Institute (ANSI) 

Z21.10.3, Gas Water Heaters—Volume 

III, Storage Water Heaters With Input 

Ratings Above 75,000 Btu Per Hour, 

Circulating and Instantaneous, and 

provides a method for determining the 

thermal efficiency and standby loss of 

this equipment. 

In addition to the test procedure 

review provision discussed above, EISA 

2007 also amended EPCA to require 

DOE to amend its test procedures for all 

covered consumer products to include 

measurement of standby mode and off 

mode energy consumption. (42 U.S.C. 

6295(gg)(2)(A)) Consequently, DOE 

recently completed a rulemaking to 

consider amending its test procedure for 

residential water heaters to include 

provisions for measuring the standby 

mode and off mode energy consumption 

of those products. Pursuant to the 

requirements of EPCA, DOE published a 

notice of proposed rulemaking (NOPR) 

in the Federal Register on August 30, 

2010, for three different residential 

heating products (water heaters, pool 

heaters, and direct heating equipment) 

related to standby mode and off mode 

energy consumption, but the NOPR 

proposed no amendments to the DOE 

test procedure for residential water 

heaters because DOE tentatively 

concluded that standby mode and off 

mode energy consumption was already 

accounted for in the existing DOE test 

method.5 75 FR 52892, 52895. 

Subsequently, DOE published a final 

rule in the Federal Register on 

December 17, 2012, which affirmed its 

conclusion that no changes were needed 

to the existing test procedure for 

residential water heaters. 77 FR 74559, 

74561–62. However, that rulemaking 

was limited to consideration of test 

procedure amendments to address the 

above-referenced standby mode and off 

mode requirements; it did not address 

other issues regarding DOE’s existing 

test procedure for residential water 

heaters. DOE addresses these issues in 

this final rule. 

On October 12, 2011, DOE published 

in the Federal Register a request for 

information (RFI) that identified and 

requested comment on a number of 

issues regarding the test procedures for 

residential water heaters. 76 FR 63211. 

DOE accepted comments and 

information on the RFI until November 

28, 2011. Key issues discussed in the 

RFI include the scope, draw patterns, 

and test conditions for residential water 

heaters. The RFI began the process of 

fulfilling DOE’s obligation to 

periodically review its test procedures 

under 42 U.S.C. 6293(b)(1)(A) by 

initiating a rulemaking to examine all 

aspects of the DOE test procedure. 

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 residential 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 


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40544 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

6ACEEE submitted a joint comment on behalf of 

ACEEE, the Appliance Standards Awareness Project 

(ASAP), the Alliance to Save Energy (ASE), 

Consumers Union (CU), the National Consumer 

Law Center (NCLC), the Natural Resources Defense 

Council (NRDC), and the Northeast Energy 

Efficiency Partnership (NEEP). 

descriptor. (42 U.S.C. 6295(e)(5)(C)) 

AEMTCA requires that, beginning one 

year after the date of publication of 

DOE’s final rule establishing the 

uniform descriptor, the efficiency 

standards for covered water heaters 

must be denominated according to the 

uniform efficiency descriptor 

established in the final rule (42 U.S.C. 

6295(e)(5)(D)), and that DOE must 

develop a mathematical 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)(i)–(ii)) After the effective 

date of the final rule, covered water 

heaters 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, if the covered 

water heater was manufactured prior to 

the effective date of the final rule and 

complies with the efficiency standards 

and labeling requirements in effect prior 

to 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, 

including: (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)) 

On January 11, 2013, DOE published 

in the Federal Register an RFI 

(hereinafter the ‘‘January 2013 RFI’’) 

that requested comment on its 

interpretation of the requirements for 

developing a uniform efficiency 

descriptor in AEMTCA. DOE also 

sought comment on how to implement 

those requirements. 78 FR 2340. DOE 

accepted comments and information on 

the RFI until February 11, 2013. 

On November 4, 2013, DOE published 

a NOPR in the Federal Register 

(hereinafter the ‘‘November 2013 

NOPR’’) regarding the test procedure for 

residential and certain commercial 

water heaters. DOE accepted comments 

and information on the NOPR until 

January 21, 2014. The November 2013 

NOPR proposed to modify the current 

test procedures for residential water 

heaters and certain commercial water 

heaters 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 water heaters and certain 

residential water heaters that are not 

covered by the current test procedure. 

The proposal also included a number of 

other improvements identified by 

commenters in response to both the 

October 2011 RFI and the January 2013 

RFI. On December 6, 2013, DOE held a 

public meeting to discuss the test 

procedure proposals outlined in the 

November 2013 NOPR. The feedback 

received from stakeholders was taken 

into consideration and is discussed 

further in section III of this final rule. 

II. Summary of the Final Rule 

Through this final rule, DOE amends 

its test procedure for residential water 

heaters and certain commercial water 

heaters. The amendments will modify 

the test procedure to be more 

representative of conditions 

encountered in the field (including 

modifications to the test conditions and 

the draw patterns) and expand the scope 

of the test procedure to apply to certain 

commercial water heaters and certain 

residential water heaters that are not 

covered by the current test procedure. 

The following paragraphs summarize 

these changes. 

DOE also modifies the test procedure 

for water heaters to establish a uniform 

descriptor that can be applied to: (1) All 

residential water heaters (including 

certain residential water heaters that are 

covered products under EPCA’s 

definition of ‘‘water heater’’ at 42 U.S.C. 

6291(27), but that are not covered under 

the current test procedure); and (2) to 

certain commercial water heaters that 

have residential applications. These 

modifications include the establishment 

of test procedure provisions that are 

applicable to water heaters with storage 

volumes between 2 gallons (7.6 L) and 

20 gallons (76 L), and the creation of a 

definition for ‘‘electric instantaneous 

water heater.’’ In addition, DOE 

establishes a new equipment class of 

commercial water heaters and 

corresponding definition for 

‘‘residential-duty commercial water 

heater.’’ DOE will require water heaters 

that are classified as ‘‘residential-duty 

commercial’’ to be tested using the test 

procedure for the uniform efficiency 

descriptor established in this final rule. 

In addition, DOE establishes the use 

of multiple draw patterns for testing 

water heaters, with certain draw 

patterns prescribed as a function of 

equipment capacity. Further, DOE 

establishes updates to the water heater 

draw pattern to be more reflective of 

actual field usage based on recent field 

test data. Lastly, DOE modifies the 

outlet water temperature requirement to 

better reflect conditions encountered in 

typical field installations. 

III. Discussion 

In response to the November 2013 

NOPR, DOE received 24 written 

comments from the following interested 

parties: Thomas Harman, Seisco, 

Applied Energy Technology (AET), two 

separate comments from Heat Transfer 

Products, Inc. (HTP), the National 

Propane Gas Association (NPGA), 

Bradford White, A.O. Smith, Edison 

Electric Institute (EEI), a joint comment 

from Northwest Energy Efficiency 

Alliance (NEEA) and Northwest Power 

and Conservation Council (NPCC) 

(NEEA and NPCC), Sequentric Energy 

Systems, LLC (SES), Stone Mountain 

Technologies (SMT), six separate 

comments from Affiliated International 

Management, LLC (AIM), the American 

Gas Association (AGA), Rheem 

Manufacturing Company (Rheem), the 

Air-Conditioning, Heating, and 

Refrigeration Institute (AHRI), Giant 

Factories, Inc. (Giant), a joint comment 

submitted by the American Council for 

an Energy-Efficient Economy (ACEEE) 

(Joint Comment),6 and General Electric 

Company (GE). 

These interested parties commented 

on a range of issues, including those 

identified by DOE in the October 2011 

RFI, the January 2013 RFI, and the 

November 2013 NOPR, as well as 

several other pertinent issues. The 

issues on which DOE received 

comment, as well as DOE’s response to 


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Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40545 

7As provided by 42 U.S.C. 6295(e)(5)(F), DOE is 

excluding from the uniform efficiency descriptor 

certain commercial water heaters that do not have 

a residential use, can be clearly described in the 

final rule, and are effectively rated using the 

thermal efficiency and standby loss descriptors. The 

water heaters that DOE is excluding are discussed 

further in section III.A.1. 

8All references to comments received in response 

to the November 2013 NOPR identify the 

commenter, the identification number applied by 

DOE, and the page of the comment package on 

which the particular point has been discussed. 

9As discussed in the NOPR, DOE determined that 

the current metrics for commercial water heaters 

that are used only in commercial settings (i.e., non- 

‘‘residential-duty’’ commercial water heaters) are 

appropriate and adequate to characterize the 

performance of such commercial water heaters due 

to the typical operating patterns of such equipment. 

78 FR 66202, 66206 (Nov. 4, 2013). 

those comments and the resulting 

changes to the test procedures for water 

heaters, are discussed in the subsections 

immediately below. 

A. Scope 

DOE’s current test procedures for 

residential water heaters codified at 10 

CFR 430.23(e) and 10 CFR part 430, 

subpart B, appendix E address gas-fired, 

electric, and oil-fired storage-type (i.e., 

storage volume not less than 20 gallons 

(76 L)) and gas-fired and electric 

instantaneous type (i.e., storage volume 

less than 2 gallons (7.6 L)) water heaters. 

However, the current DOE test 

procedure does not define ‘‘electric 

instantaneous water heater.’’ In 

addition, it does not address the 

following types of products: (1) Gasfired water heaters that have a storage 

volume at or above 2 gallons and less 

than 20 gallons (76 L); (2) electric 

storage water heaters with storage 

volume less than 20 gallons (76 L); and 

(3) storage water heaters with very large 

storage capacities, including oil-fired 

water heaters with storage volumes 

greater than 50 gallons (190 L), gas-fired 

water heaters with storage volumes 

above 100 gallons (380 L), and electric 

water heaters with storage volumes 

above 120 gallons (450 L). In the NOPR, 

DOE proposed an expansion of the 

scope of coverage of its test method so 

that it applies to all products that meet 

the definition of residential water 

heater, including those products listed 

above that are not addressed by the 

existing DOE test method. 78 FR 66202, 

66205 (Nov. 4, 2013). DOE also 

proposed revising 10 CFR 430.32(d) to 

clarify the applicability of the existing 

standards with respect to the expanded 

test procedure scope. Id. As discussed 

below, DOE adopts the proposed 

changes along with several clarifications 

based on comments received from 

interested parties. 

DOE’s test procedures for commercial 

water heaters are found at 10 CFR 

431.106. In terms of capacity, the 

procedures for commercial water 

heaters cover storage water heaters with 

an input rating up to 4,000 British 

thermal units (Btu) per hour (Btu/h) per 

gallon of stored water, instantaneous 

water heaters with input ratings not less 

than 4,000 Btu/h per gallon of stored 

water, and hot water supply boilers with 

input ratings from 300,000 Btu/h to 

12,500,000 Btu/h and of at least 4,000 

Btu/h per gallon of stored water. Models 

using natural gas, oil, or electricity are 

covered by these test methods. 

EPCA includes definitions for both 

residential and commercial water 

heaters that set the scope of DOE’s 

authority for these products. (42 U.S.C. 

6291(27); 42 U.S.C. 6311(12)) As 

required by AEMTCA, by this final rule, 

DOE establishes a uniform metric and 

test method for all covered water 

heaters,7 regardless of whether a 

particular water heater falls under the 

scope of residential water heaters or 

commercial water heaters as defined in 

EPCA. In doing so, DOE also expands 

the scope of the test procedure to 

include test methods for certain product 

types that are not covered by the current 

DOE test procedure. DOE identified 

these topics as issues for comment in 

the October 2011 RFI, the January 2013 

RFI, and the November 2013 NOPR. 76 

FR 63211, 63212–13 (Oct. 12, 2011); 78 

FR 2340, 2344–2346 (Jan. 11, 2013); 78 

FR 66202, 66205–66224 (Nov. 4, 2013). 

1. Coverage Range of Uniform Metric 

and Test Procedure 

As proposed in the November 2013 

NOPR, and in accordance with 

AEMTCA (42 U.S.C. 6295(e)(5)(F)), DOE 

excludes from the uniform efficiency 

descriptor any specific categories of 

covered water heaters that do not have 

a residential use, can be clearly 

described in the final rule, and are 

effectively rated using the current 

thermal efficiency and standby loss 

descriptors. In the November 2013 

NOPR, DOE proposed to define a new 

classification of commercial water 

heaters for which the uniform efficiency 

descriptor would apply, which DOE 

believes can be clearly distinguished 

from the commercial water heaters for 

which the uniform descriptor would not 

apply under this final rule; DOE 

proposed to name the new classification 

‘‘light commercial water heater.’’ 78 FR 

66202, 66206 (Nov. 4, 2013). DOE 

received 4 comments on this proposal in 

response to the NOPR. AHRI, AIM, A.O. 

Smith, and NEEA and NPCC suggested 

that the proposed name could lead to 

confusion. (AHRI, No. 75 at p. 2; AIM, 

No. 67 at p. 1; A.O. Smith, No. 62 at p. 

1; NEEA and NPCC No. 64 at p. 3).8

Further, AHRI and A.O. Smith 

suggested that a more appropriate name 

for this product classification would be 

‘‘residential-duty water heater.’’ (AHRI, 

No. 75 p. 2; A.O. Smith, No. 62 at p. 1) 

DOE considered this comment and 

agrees that ‘‘light commercial’’ is a term 

already used in industry and that using 

this term in this context could cause 

stakeholder and consumer confusion. 

Thus, DOE adopts a new name for the 

classification, as suggested by 

commenters, and creates a ‘‘residentialduty’’ commercial water heater 

classification.9

In the November 2013 NOPR, DOE 

proposed three characteristics to 

distinguish water heaters intended only 

for commercial use: (1) For models 

requiring electricity, uses three-phase 

power supply; (2) is capable of 

delivering hot water at temperatures of 

180 °F or above; and/or (3) bears a Code 

Symbol Stamp signifying compliance 

with the requirements of the American 

Society of Mechanical Engineers 

(ASME) Boiler and Pressure Vessel 

Code. DOE did not propose input and 

storage capacity criteria to differentiate 

commercial water heaters that would 

only be used in non-residential 

applications from commercial water 

heaters that could have residential 

applications, given that changes to the 

input and storage capacity criteria 

would likely occur over time and 

require updating. 78 FR 66202, 66206– 

66207 (Nov. 4, 2013). 

No comments were received opposing 

the proposal to exclude from the 

‘‘residential-duty commercial water 

heater’’ classification any water heater 

which uses three-phase power, so DOE 

has decided to retain that characteristic 

in this final rule. 

Five comments (AHRI, A.O. Smith, 

Bradford White, Giant, Joint Comment) 

requested that the language ‘‘capable of 

delivering’’ water at 180 °F or more 

should be changed to ‘‘designed to 

deliver,’’ given that the delivery 

temperature of a water heater is a result 

of the field conditions and usage. These 

commenters also pointed out that even 

a water heater that is not designed to 

deliver water at or above 180 °F might 

be capable of doing so. (AHRI, No. 75 

at pp. 1–2; A.O. Smith, No. 62 at p. 5; 

Bradford White, No. 61 at pp. 2–3; 

Giant, No. 76 at p. 1; Joint Comment, 

No. 77 at p. 5) 

Four commenters (AHRI, A.O. Smith, 

Giant, Joint Comment) stated that the 

ASME Boiler and Pressure Vessel Stamp 

is not required in all jurisdictions and 

would not adequately classify a water 

heater as a commercial water heater 


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without a residential application. 

(AHRI, No. 75 at p. 2; A.O. Smith, No. 

62 at p. 4; Giant, No. 76 at p. 1; Joint 

Comment, No. 77 at p. 5) 

Nine comments (AHRI, A.O. Smith, 

EEI, Giant, NEEA and NPCC, Joint 

Comment, Rheem, SMT, Seisco) 

suggested the addition of input and 

storage capacity criteria, stating that the 

three criteria listed above do not 

adequately distinguish water heaters not 

intended for residential use. (AHRI, No. 

75 at p. 2; A.O. Smith, No. 62 at p. 4; 

EEI, No. 63 at p. 5; Giant, No. 76 at pp. 

1–2; NEEA and NPCC, No. 64 at p. 3; 

Joint Comment, No. 77 at p. 4; Rheem, 

No. 69 at p. 2; SMT, No. 66 at p. 1; 

Seisco, No. 57 at p. 11) The suggested 

criteria are presented in Table III.1 and 

are grouped by water heater type. 

TABLE III.1—SUGGESTED CAPACITY CRITERIA FOR DEFINING NON-RESIDENTIAL WATER HEATERS

Water heater type Indicator of non-residential application by commenter 

Gas-fired Storage .... AHRI, A.O. Smith, Giant, Rheem: Rated input >100 kBtu/h; Rated storage volume >100 gallons. 

Oil-fired Storage ...... AHRI, A.O. Smith, Giant, Rheem: Rated input >140 kBtu/h; Rated storage volume >50 gallons. 

NEEA and NPCC: Rated input >105 kBtu/h; Rated storage volume >120 gallons. 

Electric Storage ....... AHRI, A.O. Smith, Giant, Rheem: Rated input >12kW; Rated storage volume >120 gallons. 

NEEA and NPCC: Rated input >12kW; Rated storage volume <2 gallons and >120 gallons. 

Heat Pump with 

Storage.

AHRI, A.O. Smith, Giant, Rheem: Rated current >24 A at a rated voltage of not greater than 250 V; Rated storage volume >120 gallons. 

NEEA and NPCC; 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.AHRI, A.O. Smith, Giant, Rheem: Rated input >200 kBtu/h; Rated storage volume < 1 gallon per 4000 Btu/h of input. 

NEEA and NPCC: Rated input >200 kBtu/h; Rated storage volume <2 gallons. 

Electric Instantaneous.AHRI, A.O. Smith, Giant, Rheem: Rated input >25 kW; Rated storage volume >2 gallons. 

NEEA and NPCC: Rated input >58.6 kW; Rated storage volume >2 gallons. 

Siesco: Rated input >56 kW (at a minimum). 

Oil-fired Instantaneous.AHRI, A.O. Smith, Giant, Rheem: Rated input >210 kBtu/h; Rated storage volume >2 gallons. 

Upon considering these comments, 

DOE decided to modify the criteria for 

distinguishing water heaters intended 

only for non-residential, commercial 

use. First, upon examining the 

commercial water heaters available on 

the market, DOE found that many water 

heaters that are marketed for residential 

applications and would otherwise be 

classified as ‘‘residential-duty’’ would 

be exempted from coverage under the 

uniform efficiency descriptor because of 

the requirement that ‘‘residential-duty’’ 

units be capable of delivering water at 

temperatures only up to 180 °F. (In the 

November 2013 NOPR, DOE proposed 

that ‘‘residential-duty’’ units would be 

capable of delivery water temperature 

up to but not including 180 °F. 78 FR 

66202, 66246 (Nov. 4, 2013).) As stated 

in section I, AEMTCA requires that the 

test method apply, to the maximum 

extent practicable, to all water-heating 

technologies currently in use (42 U.S.C. 

6295(e)(5)(H)), except for specific 

categories of 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)). DOE believes that the 

proposed criteria to distinguish water 

heaters intended only for commercial 

use based on the capability to deliver 

hot water at temperatures of 180 °F or 

above would have inappropriately 

excluded commercial water heaters 

marketed for residential applications, 

because such models are designed to 

include 180 °F as the maximum delivery 

temperature. However, DOE believes 

that including 180 °F as the maximum 

delivery temperature of ‘‘residentialduty’’ commercial water heaters is still 

a valuable distinguishing feature 

between water heaters intended for 

residential use and those that are not. 

DOE also agrees with commenters to 

adjust the language of the 180 °F 

delivery temperature criteria to read 

‘‘designed to deliver’’ as opposed to 

‘‘capable of delivering,’’ because a water 

heater that is ‘‘designed to deliver’’ hot 

water at or below 180 °F might be 

capable of delivering hot water in excess 

of 180 °F depending on the field 

conditions and usage. DOE is aware of 

situations where a water heater could be 

subjected to a series of several short 

draws, which can cause an influx of 

cold water at the bottom of the tank. 

Due to stratification, the water at the 

bottom of the tank near the thermostat 

may be colder than the water at the top 

of the tank, causing the burner or 

elements to turn on and heat the water 

to a temperature above that for which 

the water heater is designed. DOE 

considers a water heater that is 

‘‘designed to deliver’’ water at or below 

180 °F as one that has a user-operable 

temperature control device with a 

maximum setting of 180 °F or a 

maximum setting that would deliver 

water at or below 180 °F under the 

conditions defined by the test method. 

In order to more closely match the 

language of the test procedure when 

defining water heaters, DOE is slightly 

changing the wording from ‘‘designed to 

deliver water’’ to ‘‘designed to provide 

outlet water.’’ 

Second, because the ASME Boiler and 

Pressure Vessel Stamp criterion is not 

required in all jurisdictions and because 

this criterion is not a definitive 

identifier of whether a unit is truly 

commercial, DOE does not adopt this 

proposed requirement. Rather, as 

suggested by commenters, DOE adopts 

limitations on input rating and storage 

capacity. (Additional comments related 

to storage capacity and input capacity 

limitations are discussed in the 

subsections immediately following this 

section.) DOE agrees that water-heating 

units exist in the current marketplace 

that are not intended for residential use 

that do not meet the three criteria 

proposed in the November 2013 NOPR 

(and listed above) and, thus, establishes 

input and storage capacity criteria based 

on water heater type as shown in Table 

III.2. Although DOE still believes that 

changes to the input and storage 

capacity criteria could occur over time 

and require these criteria to be updated, 

DOE has concluded that these criteria 

are necessary to properly classify the 

scope of the uniform efficiency 

descriptor. 


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TABLE III.2—CAPACITY CRITERIA FOR

DEFINING NON-RESIDENTIAL WATER

HEATERS

Water heater 

type 

Indicator of non-residential 

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 establishes a definition of 

‘‘residential-duty commercial water 

heater’’ at 10 CFR 431.102 that defines 

a ‘‘residential-duty commercial water 

heater’’ as any gas-fired, electric, or oil 

storage or instantaneous commercial 

water heater that meets the following 

conditions: 

(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 °F; and 

(3) Is not excluded by the specified 

limitations regarding rated input and 

storage volume as described in Table 

III.2 above. 

Although residential-duty commercial 

water heaters could have residential 

applications, DOE notes that the new 

‘‘residential-duty commercial water 

heater’’ definition represents a type of 

water heater that, to a significant extent, 

is distributed in commerce for industrial 

or commercial use. These water heaters 

were and continue to be covered 

industrial equipment, and will continue 

to be subject to the applicable energy 

conservation standards in 10 CFR part 

431 and the certification requirements 

for commercial and industrial 

equipment in 10 CFR part 429. 

Similarly, although DOE recognizes that 

some consumer water heaters may be 

installed in a commercial setting, those 

water heaters are covered consumer 

products for the purposes of DOE 

regulations; the applicable energy 

conservation standards in 10 CFR part 

430 continue to apply; and they must be 

certified as consumer products under 10 

CFR part 429. 

If a commercial water heater does not 

meet all of the three conditions 

discussed above, it would be classified 

as a commercial water heater that would 

not be expected to be used in residential 

applications and would be subject to the 

current test methods prescribed in 10 

CFR 431.106 and the certification 

requirements for commercial and 

industrial equipment in 10 CFR part 

429. If a commercial water heater meets 

all three criteria, DOE will consider it a 

‘‘residential-duty commercial water 

heater,’’ which would be subject to the 

uniform efficiency descriptor and test 

method established in this final rule. 

Accordingly, DOE is adding a row to 

Table 1 of 10 CFR 431.106 specifying 10 

CFR part 430, subpart B, appendix E as 

the test method for this type of 

equipment. 

As stated in the November 2013 

NOPR, 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. 78 FR 66202, 

66207 (Nov. 4, 2013). Unfired storage 

tanks are not complete water-heating 

systems and require additional 

equipment in the field to operate. As 

such, their performance as part of a 

complete water-heating system is 

dependent upon other components of 

the system so that use of the uniform 

descriptor may be unrepresentative of 

its performance as part of a complete 

water-heating system. In a similar vein, 

DOE previously determined that 

residential add-on heat pump water 

heaters are not covered residential 

products. 75 FR 20112, 20127 (Apr. 16, 

2010). DOE has authority to cover 

commercial add-on heat pumps; 

however, this equipment does not have 

residential applications and, therefore, 

is not suitable for application of the 

uniform efficiency descriptor. DOE also 

determined that hot water supply 

boilers are more appropriately rated 

using the existing metrics for 

commercial water heaters, as this 

equipment has very high input ratings 

and their use is similar to that of other 

commercial water heaters in commercial 

applications. 78 FR 66202, 66207 (Nov. 

4, 2013). DOE will address the types of 

commercial water-heating equipment 

that are excluded from the uniform 

descriptor (e.g., unfired storage tanks, 

add-on heat pump water heaters, and 

hot water supply boilers) in a 

subsequent test procedure rulemaking. 

DOE did not receive any comments 

regarding the exclusion of unfired 

storage tanks, add-on heat pump water 

heaters, and hot water supply boilers 

from coverage under the uniform 

descriptor. 

2. Storage Capacity Limits 

As noted above, under the existing 

regulatory definitions, DOE’s current 

residential water heater test procedures 

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). The current DOE 

test procedure for residential 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 oilfired 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. 

The definitions in the current DOE 

test procedure specify that gas 

instantaneous water heaters have a 

storage volume of less than two gallons 

(7.6 L) and that electric or gas storagetype water heaters have a storage 

volume of 20 gallons (76 L) or more. The 

storage capacity of oil water heaters in 

the test method is not restricted by a 

lower limit, with the specification 

stating that an oil-fired storage water 

heater simply has a rated capacity less 

than or equal to 50 gallons (190 L). 10 

CFR part 430, subpart B, appendix E, 

sections 1.7 and 1.12. The definitions 

for ‘‘Electric Instantaneous Water 

Heater’’ and ‘‘Storage-type Water Heater 

of More than 2 Gallons (7.6 Liters) and 

Less than 20 Gallons (76 Liters)’’ are 

currently reserved. Id. at section 1.12.5. 

In the 1998 rulemaking establishing 

test procedures for residential water 

heaters, DOE proposed to include units 

with storage volumes between 2 and 20 

gallons, but commenters raised concerns 

that the test procedure demand of 64.3 

gallons per day was not appropriate for 

these small units. 63 FR 25996, 26000 

(May 11, 1998). At that time, DOE 

concluded that the data necessary to 

determine an appropriate representative 

daily hot water consumption for water 

heaters with these storage volumes did 

not exist and that alternative procedures 

proposed by commenters were not fully 

evaluated. For these reasons, the 

Department tabled consideration of the 

inclusion of these water heaters until a 

future revision of the DOE test 

procedure. 

As proposed in the November 2013 

NOPR, DOE has decided to expand the 

scope of the water heater test procedure 

for the uniform efficiency descriptor to 


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40548 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

include water heaters with storage 

volumes between 2 and 20 gallons. 78 

FR 66202, 66208 (Nov. 4, 2013). Rheem 

supported the expansion of the scope to 

include units between 2 and 20 gallons, 

but asserted that these products should 

not be covered by the current energy 

conservation standards. (Rheem, No. 69 

at pp. 7–8) Bradford White requested 

clarification as to whether products 

between 2 and 20 gallons would be 

covered by the current energy 

conservation standards or test procedure 

only. (Bradford White, No. 61 at p. 2) 

AHRI stated that, although DOE is 

developing a test method for water 

heaters with storage volumes between 2 

and 20 gallons, the current DOE 

minimum efficiency standards for 

residential water heaters do not and 

should not apply to models having rated 

storage volumes less than 20 gallons, 

and AHRI requested information 

regarding DOE activities with regard to 

standards for these products. (AHRI, No. 

80 at pp. 2–3) 

The test procedure modifications for 

water heaters with a storage volume 

between 2 and 20 gallons specify the 

method of test set-up (including 

instrumenting such water heaters), a test 

method to assess the delivery capacity, 

and the draw pattern to be used to 

determine the energy efficiency of such 

units. The amendments for water 

heaters with storage volumes between 2 

and 20 gallons are discussed in detail in 

section III.C of this final rule. Currently, 

there are no minimum energy 

conservation standards applicable to 

water heater products with a storage 

volume between 2 and 20 gallons, 

which will be the case until DOE 

conducts a rulemaking to establish such 

standards. DOE clarifies this point in 

this final rule’s amendments to 10 CFR 

430.32(d). 

AEMTCA requires DOE to reconsider 

the scope of all water heater test 

procedures. AEMTCA amended EPCA 

to require that the new uniform metric 

apply to the extent possible to all waterheating technologies. (42 U.S.C. 

6295(e)(5)(F) and (H)) 

In considering the upper limit to the 

storage capacity range, DOE is not aware 

of any residential water heaters 

available on the market with storage 

volumes above 100 gallons, 120 gallons, 

and 50 gallons for gas-fired, electric 

(resistance and heat pump), and oilfired water heaters, respectively, that 

would be covered as residential 

products under EPCA. AHRI, A.O. 

Smith, Giant, and Rheem supported the 

continued use of the current maximum 

storage capacity limits. (AHRI, No. 75 at 

p. 2; A.O. Smith, No. 62 at p. 4; Giant, 

No. 76 at p. 2; Rheem, No. 69 at p. 2) 

In contrast, as AET stated in response 

to the January 2013 RFI, the ASME 

Boiler and Pressure Vessel Code 

requires that vessels intended to store 

fluids under pressure must individually 

undergo a rigorous test and inspection 

procedure if they have volumes greater 

than 120 gallons. AET noted that 

because these test and certification 

procedures are expensive, 

manufacturers will avoid making 

products intended for residential use 

that require an ASME inspection and 

code stamp. For this reason, AET 

commented that the upper limit of 120 

gallons would be appropriate for all 

residential water heaters. (AET, No. 22 

at pp. 6–7) 

DOE has reconsidered the water 

heater test procedure scope and expands 

the scope of the test procedure to 

include all covered water heaters that 

could have residential applications and 

adjusts the current limitations on 

maximum storage volume in the 

residential test procedure for gas-fired, 

electric, and oil storage water heaters to 

120 gallons for all three types. DOE 

concludes that the amended test method 

adopted in today’s final rule adequately 

addresses water heaters regardless of 

storage volume, provided that they meet 

the definition of a ‘‘residential water 

heater’’ or a ‘‘residential-duty 

commercial water heater.’’ 

Consequently, DOE’s uniform descriptor 

test procedure will apply to residential 

storage water heaters and ‘‘residentialduty commercial water heaters’’ with 

storage volumes up to 120 gallons. As 

noted previously in section III.A.1, DOE 

excludes non-residential (commercial) 

water heaters, and DOE agrees with AET 

that a storage capacity limit of 120 

gallons adequately separates residential 

and commercial units of all water heater 

types. 

3. Input Capacity Limits 

AEMTCA requires that the new 

uniform efficiency descriptor apply to 

the maximum extent practical to all 

water-heating technologies in use now 

or in the future. (42 U.S.C. 

6295(e)(5)(H)) DOE’s current residential 

water heater test procedure is 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 is 

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. 10 

CFR part 430, subpart B, appendix E, 

section 1.12. 

In the November 2013 NOPR, DOE 

proposed to eliminate the minimum 

limit on the firing rate of instantaneous 

gas water heaters of 50,000 Btu/h. 78 FR 

66202, 66209 (Nov. 4, 2013). As 

discussed in section III.C, DOE adopts 

multiple draw patterns that vary based 

on the delivery capacity of the water 

heater. Because the draw pattern is 

dependent upon delivery capacity, gasfired instantaneous units with a firing 

rate below 50,000 Btu/h can be tested 

under the new procedure. Thus, DOE 

has concluded that there is no reason to 

retain this lower limit on gas-fired 

instantaneous water heater delivery 

capacity. No comments were received 

opposing this measure. 

Similarly, DOE proposed to remove 

the maximum input ratings for gas-fired, 

electric, and oil-fired storage water 

heaters and for gas-fired instantaneous 

water heaters from the test procedure 

(although maximum input ratings 

specified in EPCA would still apply for 

the purposes of equipment 

classification). Because draw patterns 

vary based on delivery capacity, the 

new test procedure applies to models 

with input capacities above those 

included in the current residential water 

heater test procedure. Although these 

maximum input limitations were based 

upon EPCA’s ‘‘water heater’’ definition 

at 42 U.S.C. 6291(27), because the 

AEMTCA amendments require that the 

new metric apply to all water-heating 

technologies except those that do not 

have a residential use, DOE believes that 

such limits are no longer controlling or 

appropriate in terms of the scope of the 

water heaters test procedure. DOE did 

not receive any comments in response 

to the NOPR related specifically to the 

inclusion of input limitations on 

residential products in the test 

procedure, but did receive comments 

regarding the application of the test 

procedure to commercial models and 

suggesting input capacity limitations. 

Those comments are discussed in 

section III.A.1. As discussed in section 

III.A.1, input rating limitations are 

useful to distinguish water heaters 

without a residential use. Therefore, 

although DOE will remove the input 

capacity limitations from the scope of 

the test method, DOE establishes input 

capacity limits to define which units 

would qualify as ‘‘residential-duty’’ 

commercial units and, thus, be required 

to be tested using the uniform descriptor 

test method. These input capacity 

limitations are shown in Table III.2 

above. 


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Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40549 

4. Electric Instantaneous Water Heaters, 

Gas-Fired Heat Pump Water Heaters, 

and Oil-Fired Instantaneous Water 

Heaters 

As discussed in the November 2013 

NOPR, DOE’s test procedures do not 

contain a definition for ‘‘electric 

instantaneous water heater,’’ but rather 

have a space reserved to define that 

term (10 CFR part 430, subpart B, 

appendix E, section 1.7.1). 78 FR 66202, 

66209 (Nov. 4, 2013). EPCA defines 

‘‘electric instantaneous water heater’’ as 

containing no more than one gallon of 

water per 4,000 Btu per hour of input 

and having an input capacity of 12 

kilowatts (kW) or less. (42 U.S.C. 

6291(27)(B)) As noted in the November 

2013 NOPR, the heating power required 

for electric instantaneous water heaters 

intended for whole-home applications 

typically is much higher than the power 

capability commonly found in storagetype electric water heaters. 78 FR 66202, 

66209 (Nov. 4, 2013). In the November 

2013 NOPR, DOE proposed to amend its 

water heater test procedure to include 

applicable provisions for electric 

instantaneous water heaters, and to 

define the term ‘‘electric instantaneous 

water heater.’’ Id. at 66210. 

AIM commented that DOE needs to be 

more inclusive of all types of water 

heaters when defining the types of water 

heaters that will be covered by the 

uniform descriptor. (AIM No. 70 at p. 2) 

DOE agrees in principle that all 

existing types of water heaters should be 

defined and, thus, adopts definitions of 

‘‘gas-fired heat pump water heater’’ and 

‘‘oil-fired instantaneous water heater,’’ 

in addition to a definition for ‘‘electric 

instantaneous water heater.’’ While not 

yet commercially available, DOE is 

aware that manufacturers are currently 

developing gas-fired heat pump water 

heaters and oil-fired instantaneous 

water heaters. Further, the new test 

procedure applies to these types of 

water heaters. Accordingly, DOE adds 

definitions for these types of water 

heaters at 10 CFR 430.2. (In addition, as 

proposed in the November 2013 NOPR, 

DOE is moving all other definitions 

pertaining to defining the types of water 

heaters to 10 CFR 430.2.) All three 

definitions reflect the definitions of 

these products as set forth in EPCA (42 

U.S.C. 6291(27)) and are based on the 

current definitions for other types of 

water heaters. The definition for 

‘‘electric instantaneous water heater’’ 

has been altered slightly from the 

definition proposed in the November 

2013 NOPR to better align with the 

requirements of EPCA for these 

products. These definitions read as 

follows: 

Gas-fired Heat Pump Water Heater 

means a water heater that uses gas as the 

main energy source, has a nameplate 

input rating of 75,000 Btu/h (79 MJ/h) 

or less, has a maximum current rating of 

24 amperes (including all auxiliary 

equipment such as fans, pumps, 

controls, and, if on the same circuit, any 

resistive elements) at an input voltage of 

no greater than 250 volts, has a rated 

storage capacity of 120 gallons (450 

liters) or less, and is designed to transfer 

thermal energy from one temperature 

level to a higher temperature level to 

deliver water at a thermostaticallycontrolled temperature less than or 

equal to 180 °F (82 °C). 

Oil-fired Instantaneous Water Heater 

means a water heater that uses oil as the 

main energy source, has a nameplate 

input rating of 210,000 Btu/h (220 MJ/ 

h) or less, contains no more than one 

gallon of water per 4,000 Btu per hour 

of input, and is designed to provide 

outlet water at a controlled temperature 

less than or equal to 180 °F (82 °C). The 

unit may use a fixed or variable burner 

input. 

Electric Instantaneous Water Heater 

means a water heater that uses 

electricity as the energy source, has a 

nameplate input rating of 12 kW (40,956 

Btu/h) or less, contains no more than 

one gallon of water per 4,000 Btu per 

hour of input, and is designed to 

provide outlet water at a controlled 

temperature less than or equal to 180 °F 

(82 °C). The unit may use a fixed or 

variable burner input. 

DOE notes that the definition of 

‘‘electric instantaneous water heater’’ 

being added to 10 CFR 430.2 

encompasses only electric instantaneous 

water heaters that are residential (i.e., 

with an input capacity of 12 kW or less). 

However, as discussed in section III.A.1, 

commercial (i.e., with an input capacity 

greater than 12 kW) electric 

instantaneous water heaters with input 

ratings up to 58.6 kW are considered 

‘‘residential-duty commercial water 

heaters,’’ and because water heaters 

both above and below 12 kW have 

residential applications, both types 

would be covered by the uniform 

efficiency descriptor. 

In response to the November 2013 

NOPR, Seisco and Thomas Harman 

commented that 12 kW is not an 

appropriate cutoff for electric 

instantaneous water heaters because 

there are many electric instantaneous 

water heaters designed for and used in 

residences that have input ratings above 

12 kW. (Harman, No. 53 at p. 1; Seisco, 

No. 57 at pp. 10–11) In response, DOE 

notes that the 12 kW limit is defined by 

EPCA and it is not at DOE’s discretion 

to change. However, the 12 kW criteria 

will apply only insofar as determining 

the applicable minimum energy 

conservation standard. As such, it 

remains the point above which electric 

instantaneous models would be 

classified as ‘‘commercial’’ equipment 

for the basis of determining the 

applicable energy conservation 

standards. Limits on the application of 

the uniform efficiency descriptor 

pursuant to the new test procedure 

based on input and volume capacities 

are set forth in Table III.2, above. 

This final rule also provides for a 

maximum flow rate test for electric 

instantaneous water heaters and a test to 

determine the energy efficiency 

expressed in terms of uniform energy 

factor for these products. (As discussed 

in section III.B, the energy efficiency 

metric for water heaters will be changed 

from ‘‘energy factor’’ to ‘‘uniform energy 

factor.’’) These tests are identical to 

those provided for gas-fired 

instantaneous water heaters. 

B. Uniform Efficiency Descriptor 

Nomenclature 

AEMTCA provided the following 

options for the uniform efficiency 

descriptor metric: (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)) 

In the November 2013 NOPR, DOE 

proposed to use a revised version of the 

energy factor as the uniform efficiency 

descriptor. 78 FR 66202, 66210 (Nov. 4, 

2013). DOE received no comments 

opposing the continued use of the 

energy factor metric in response to the 

November 2013 NOPR. However, DOE 

received four comments (A.O. Smith, 

Bradford White, EEI, Joint Comment) 

suggesting that the ‘‘energy factor’’ 

nomenclature be adjusted to distinguish 

the old energy factor from the new. 

Additionally, the four commenters 

suggest that the new ‘‘energy factor’’ 

nomenclature be differentiated by class 

(i.e., subscripts with the draw 

classification). (A.O. Smith No. 62 at p. 

3; Bradford White No. 61 at p. 6; EEI No. 

63 at p. 4; Joint Comment No. 77 at p. 

2) NEEA and NPCC commented that the 

‘‘energy factor’’ nomenclature as it 

currently stands is appropriate and that 

changes to the test procedure are not 

significant enough to warrant a new 

descriptor. (NEEA and NPCC No. 64 at 

p. 1) NEEA and NPCC and the Joint 

Comment stated that the new ‘‘energy 

factor’’ nomenclature should not be 

distinguished by fuel type or technology 


tkelley on DSK3SPTVN1PROD with RULES2
40550 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

10Lutz, JD, Renaldi, Lekov A, Qin Y, and Melody 

M., ‘‘Hot Water Draw Patterns in Single Family 

Houses: Findings from Field Studies,’’ Lawrence 

Berkeley National Laboratory Report number 

LBNL–4830E (May 2011) (Available at http://

www.escholarship.org/uc/item/2k24v1kj) (last 

accessed June 17, 2014). 

group. (NEEA and NPCC No. 64 at p. 16; 

Joint Comment No. 77 at p. 2) 

DOE agrees with commenters that 

confusion could occur if the name of the 

metric remains unchanged between the 

current and amended test procedures. 

Because the existing and new ratings are 

determined under different test 

conditions, which can result in a 

different rating, DOE believes it is 

necessary to adopt a new name to 

distinguish between the efficiency result 

under the existing test procedure and 

the result under the amended test 

procedure. As a result, DOE adopts a 

‘‘uniform energy factor,’’ to be denoted 

as ‘‘UEF’’ in the test procedure, as 

distinguished from the ‘‘Ef’’ rating 

determined under the current test 

procedure. 

C. Draw Pattern 

The term ‘‘draw pattern’’ describes 

the number, flow rate, length, and 

timing of hot water removal from the 

water heater during testing. Primary 

decisions in developing draw patterns 

include the total amount of water to be 

removed during the test and the number 

of draws during the test. The total 

amount of water taken in each draw, 

which is a function of the flow rate and 

the length of the draw, must also be 

specified. Finally, the spacing between 

those draws is needed to complete the 

specification of the draw pattern. 

DOE proposed to modify the draw 

pattern that is used in the existing test 

procedure in the November 2013 NOPR. 

78 FR 66202, 66210–17 (Nov. 4, 2013). 

Under DOE’s proposal, the single draw 

pattern that is currently applied during 

the 24-hour simulated use test would be 

replaced with one of four patterns that 

is more representative of the demand 

put on a water heater of different 

delivery capacity. These four draw 

patterns were termed ‘‘point-of-use,’’ 

‘‘low usage,’’ ‘‘medium usage,’’ and 

‘‘high usage.’’ The selection of the draw 

pattern to be used in the simulated-use 

test would be based upon the results of 

the first-hour rating test or the 

maximum GPM (gallons per minute) 

rating test. 

DOE received seven comments in 

general support of the move to four 

different draw patterns. (HTP No. 59 at 

p. 2; A.O. Smith No. 62 at p. 2; EEI No. 

63 at p. 4; NEEA and NPCC No. 64 at 

p. 3; AHRI No. 75 at p. 3; Giant No. 76 

at p. 3; Joint Comment No. 77 at p. 6) 

HTP recommended that DOE consider 

altering the total water drawn in the 

medium-usage pattern to 64.8 gallons to 

assist in correlating between current 

metrics and the proposed metrics. NEEA 

and NPCC indicated a slight preference 

for draw patterns proposed as part of the 

deliberations for ASHRAE 118.2, 

‘‘Method of Testing for Rating 

Residential Water Heaters,’’ because 

those draws are more consistent with 

the daily hot water use found in their 

field data. AHRI indicated that the 

proposed draw patterns were 

appropriate but that it preferred the 

draw patterns submitted in its comment 

to the January 2013 RFI. (AHRI No. 46 

at p. 5) 

DOE received one comment that 

supported the move to multiple draw 

patterns but that recommended five 

draw patterns instead of four and 

provided alternative bases for 

developing the patterns. (AET No. 58 at 

p. 3) AET commented that the proposed 

draw patterns could result in water 

being delivered during the simulateduse test that may be considered to be too 

cold for typical uses and recommended 

that a fifth category termed ‘‘Sink’’ be 

created that would apply to the smallest 

water heaters. AET discussed how the 

amount of water that can be withdrawn 

in a continuous draw can be estimated 

from the first-hour rating and stated that 

the maximum draw volumes imposed in 

the proposed draw patterns may yield 

an ‘‘invalid test.’’ Particular emphasis 

was placed on the point-of-use category, 

in which a 2-gallon water heater would 

be expected to deliver a 2-gallon draw. 

Another concern expressed by AET is 

that water heaters with the same storage 

volume but with slightly different input 

rates would be tested according to 

different draw patterns. AET suggested 

that selection of the draw pattern used 

for the simulated-use test should be 

based on two factors: the measured 

storage volume and the first-hour rating. 

AET recommended the largest draw 

volume that should be implemented in 

each draw pattern to meet the 

capabilities of the water heaters in that 

category. AET estimated that the first 

draw delivery capability of a storage 

water heater is 0.95*0.85*(Rated Storage 

Volume), where 0.95 represents the 

currently allowed tolerance on storage 

volume and 0.85 accounts for mixing of 

hot and cold water during draws. Id. 

DOE received three comments from 

AET, SMT, and Bradford White related 

to the details in the proposed test 

procedure of determining the standby 

loss coefficient, ‘‘UA,’’ which is used to 

adjust the daily energy consumption to 

account for deviations from nominal 

conditions. AET expressed concern that, 

with water heaters having very slow 

recoveries, the test could result in a 

water heater with drastically different 

stored water temperature at the start of 

the test than at the end, thereby 

necessitating a major correction to the 

energy consumed. AET recommended 

extending the test beyond 24 hours for 

such water heaters, ending the test only 

after a recovery occurs. Energy 

consumption during the test would be 

modified to normalize to a 24-hour time 

period by removing the estimated 

standby loss during the time exceeding 

24 hours. AET commented that it is 

much more accurate to normalize to a 

common time period than it is to end 

the test prior to a recovery occurring. 

AET stated that this approach would 

ensure that a recovery occurs during the 

period of the test when the UA value is 

determined and that it would result in 

an average tank temperature that 

changes less from the start of the test to 

the end of the test. (AET No. 58 at p. 1). 

SMT expressed concern that largecapacity models may not initiate 

recovery during the first draw cluster of 

tests or may initiate a recovery during 

a standby portion of the test. In these 

cases, SMT commented that 

determination of the UA may not be 

possible. SMT suggested that the test 

should start with a fully-charged water 

heater and that the first draw cluster 

should start eight hours after this point. 

According to SMT, the UA value would 

be determined during this eight-hour 

period. (SMT No. 66 at p. 2). Bradford 

White commented that the new test 

procedure can take standby loss 

readings when the water heater is 

recovering and/or when water is being 

drawn, which would lead to inaccurate 

measures of standby loss. (Bradford 

White No. 61 at p. 8). 

After consideration of these 

comments, DOE has decided to adopt 

the modifications to the draw patterns 

as originally proposed in the November 

2013 NOPR. DOE has reviewed the total 

amount of water drawn per day in each 

draw pattern and has observed that 

those values match well with field data 

collated by the Lawrence Berkeley 

National Laboratory.10 DOE 

acknowledges that a medium-use draw 

pattern having the same daily draw 

volume as that prescribed in the current 

test procedure would remove some 

uncertainty in converting from the 

existing efficiency metric to the new 

uniform metric since the total daily 

draw volume would not impact the 

rating. However, DOE has decided to 

maintain a lower daily draw volume in 

the new draw schedule to better match 


tkelley on DSK3SPTVN1PROD with RULES2
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40551 

11Test results from DOE testing for the NOPR are 

summarized in the November 2013 Water Heater 

Test Procedure Rulemaking Development Testing 

Preliminary Report, available in the rulemaking 

docket at: http://www.regulations.gov/

#!documentDetail;D=EERE-2011-BT-TP-0042-0052. 

field data available for a medium-usage 

situation. 

DOE considered adding a fifth draw 

pattern as recommended by AET, but a 

review of data from testing of lowvolume water heaters indicate that the 

efficiency can be accurately determined 

using the four proposed draw patterns. 

While delivery temperatures did drop 

below 120 °F during some draws of 

these tests, DOE has concluded that the 

efficiency is still accurately determined 

using this test procedure and that the 

added complexity of an additional draw 

pattern is not warranted. 

DOE will continue to use the firsthour rating to assign a draw pattern for 

use during the simulated-use test. DOE 

examined using a combination of firsthour rating and storage volume to 

categorize the water heater for assigning 

a draw pattern, as suggested by AET, but 

is concerned that some water heaters 

may not fit into any category because 

their storage volumes would correspond 

to one draw pattern while their firsthour ratings would correspond to a 

different one. Additionally, as noted 

above, AET estimates that the first draw 

delivery capability of a storage water 

heater is 0.95*0.85*(Rated Storage 

Volume), which accounts for the 

tolerance currently afforded 

manufacturers on storage volume and 

the effect of mixing of hot and cold 

water within the storage water heater 

during draws. DOE agrees that this 

method for estimating first draw 

delivery capacity is appropriate for 

conventional electric storage water 

heaters. However, the Department is 

concerned that the effect of mixing hot 

and cold water within the unit during 

draws is not well understood for the 

emerging water-heating technologies 

that are noted by the commenter. 

Therefore, basing the categorization of 

water heaters into usage bins (i.e., very 

small, low, medium, and high) to 

determine the appropriate draw pattern 

based on this uncertain number is likely 

to lead to miscategorization for some 

water heaters. In the end, DOE has 

decided that the first-hour rating is the 

best metric available for determining 

water heater size classification for 

purposes of efficiency testing. 

DOE is adopting the draw volumes 

proposed in the November 2013 NOPR. 

Test results 11 indicate that the draw 

volumes incorporated into the proposed 

patterns, while resulting in delivery 

temperatures that may not match the 

nominal outlet temperatures, provide a 

sufficiently accurate estimate of the 

energy efficiency and that these draw 

patterns will result in an accurate 

estimate of the efficiency of water 

heaters within each size classification. 

The flow rates and volumes specified in 

the November 2013 NOPR represent the 

best alternative for characterizing water 

heaters at both the lower and upper 

limits of a size category. 

In response to the comment from 

Bradford White stating concern that the 

standby loss coefficient (UA) can be 

determined while a recovery is 

occurring, DOE notes that there is a 

possibility of a recovery taking place 

during the portion of the test when data 

are collected to determine UA, just as 

there is the possibility in the current test 

method. The determination of UA, 

however, may require a reheat to 

maintain the stored water temperature 

to obtain a valid estimate of UA. As for 

the standby time period during which 

energy loss to the ambient is corrected, 

DOE notes that time when draws are 

taking place are omitted from the 

calculation. See section 6.3.5 of 

appendix E as adopted in this final rule. 

Therefore, DOE is making no changes in 

response to the comment. 

DOE considered amending the timing 

of the simulated-use test, as suggested 

by some commenters, to improve the 

determination of UA. DOE examined 

data from a range of simulated-use tests 

and decided that the test procedure 

requires modification to improve the 

determination of UA for some special 

cases. 

The first modification responds to 

concerns expressed about the 

determination of UA for water heaters 

with low recovery rates. DOE observed 

that the first recovery may not begin 

until several hours into the designated 

standby period and could extend into 

the second draw cluster. DOE examined 

data from tests on such water heaters 

and modified the test procedure 

provisions for determining UA in the 

event that a recovery does not begin 

during the first draw cluster. 

As proposed in the November 2013 

NOPR, the standby period for 

determination of UA was intended to 

occupy the majority of the period 

between the end of the first draw cluster 

and the start of the second draw cluster. 

78 FR 66202, 66217, 66236 (Nov. 4, 

2013). However, because the standby 

period is supposed to start at the end of 

the first recovery under the proposed 

procedure, the standby period may not 

start until well into the 24-hour test for 

water heaters with a very slow recovery 

rate. For one tested water heater, DOE 

observed that the first recovery did not 

begin until several hours past the end of 

the first draw cluster and ended after 

subsequent draws occurred during the 

test. Under the proposed test procedure, 

the standby period started at the end of 

this first recovery period and continued 

until the next draw started. This 

procedure could result in a very short 

time period for determination of UA, 

which might lead to erroneous results. 

To address this issue, DOE amends 

the proposed test procedure by starting 

the standby period five minutes 

following the last draw of the first draw 

cluster if a recovery is not occurring, as 

opposed to waiting until after the first 

recovery period ends. The end point of 

the standby period will remain as 

proposed in the November 2013 NOPR. 

This change ensures an accurate 

determination of UA for all units, 

including those with low recovery rates 

and those that delay onset of heating 

until after the first cluster of draws. 

The second clarification addresses 

water heaters that undergo a recovery 

that begins at the end of the first draw 

cluster and continues over the entire 

standby period between the first and 

second draw clusters. In these instances, 

the standby period continues past the 

end of the 24-hour test. To address this 

issue, DOE amends the test procedure to 

initiate the standby period at the end of 

the first recovery following the final 

draw and to continue measurements for 

eight hours from that point. 

DOE concludes that the approaches 

implemented in the final rule will 

determine a standby loss coefficient that 

accurately adjusts the daily energy 

consumption when the ambient 

temperature deviates from the nominal 

value during testing. The Department is 

adopting this approach, as opposed to 

the one presented by AET, in order to 

maintain a test duration of 24 hours for 

nearly all water heaters while providing 

accurate representation of the water 

heater’s energy efficiency. 

DOE received one comment 

requesting a change in the name of the 

‘‘point-of-use’’ draw pattern, stating that 

the term ‘‘point-of-use’’ describes the 

installed location of a water heater as 

opposed to the delivery capacity, which 

is the characteristic described by the 

other three category names (i.e., ‘‘low,’’ 

‘‘medium,’’ and ‘‘high’’). (AIM No. 71 at 

p. 1) AIM suggested a name of ‘‘very 

small’’ for this category. DOE agrees in 

principle with this comment and has 

decided to change the name of the 

‘‘point-of-use’’ category to ‘‘very-smallusage.’’ 

Bradford White commented that the 

tolerances of +/¥0.25 gallons for the 

volume removed in each draw in the 

proposed test procedure could lead to 


tkelley on DSK3SPTVN1PROD with RULES2
40552 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

large discrepancies in the overall 

volume removed, which could in turn 

necessitate a test laboratory to skip a 

final draw to achieve the overall 

tolerance of +/¥1 gallon for the daily 

water delivery. (Bradford White No. 61 

at pp. 8–9) DOE agrees with this 

observation and is tightening the 

tolerances on some draws in the final 

rule. For draws taken at a nominal flow 

rate of 1.7 GPM or less, DOE is requiring 

that those draws have a tolerance of 

+/¥0.1 gallons. With the data 

acquisition rate during draws set to 3 

seconds, DOE believes that this level of 

tolerance is achievable. At the nominal 

flow rate of 3 GPM, however, the 

frequency of data collection may not 

allow for such tight control of draw 

volumes during each draw, so DOE is 

maintaining the tolerance of +/¥0.25 

GPM for those draws. DOE is already 

increasing the frequency of data 

collection and does not believe it is 

necessary to increase it further to allow 

for a stricter tolerance on 3 GPM draws. 

DOE notes that only the high-usage 

pattern contains draws with a flow rate 

of 3 GPM, and only 3 of the 14 draws 

are at that flow rate. As a result, DOE 

expects that the overall tolerance of 

+/¥1 gallon for the daily water delivery 

can be achieved because the tighter 

tolerance applies to the remaining 11 

draws. 

DOE acknowledges that, given the 

tolerances on individual draws, a 

situation may arise whereby the volume 

of the final draw would need to be 

adjusted downward so much that a 

draw volume of zero may be required to 

meet the overall tolerance on the daily 

draw volume. DOE concludes that this 

scenario would result in an invalid test 

and has inserted a statement in the test 

procedure indicating that ‘‘if this 

adjustment to the volume drawn in the 

last draw results in no draw taking 

place, the test is considered invalid.’’ 

Table III.3 through Table III.6 show the 

draw patterns that DOE is adopting. 

TABLE III.3—VERY-SMALL-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (L)] 

Flow rate ** 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 2.0 (7.6) 1 (3.8) 

2 * ......................................................................................................................... 1:00 1.0 (3.8) 1 (3.8) 

3 * ......................................................................................................................... 1:05 0.5 (1.9) 1 (3.8) 

4 * ......................................................................................................................... 1:10 0.5 (1.9) 1 (3.8) 

5 * ......................................................................................................................... 1:15 0.5 (1.9) 1 (3.8) 

6 ........................................................................................................................... 8:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 8:15 2.0 (7.6) 1 (3.8) 

8 ........................................................................................................................... 9:00 1.5 (5.7) 1 (3.8) 

9 ........................................................................................................................... 9:15 1.0 (3.8) 1 (3.8) 

Total Volume Drawn Per Day: 10 gallons (38 L) 

* Denotes draws in first draw cluster. 

** Should the water heater have a maximum GPM rating less than 1 GPM (3.8 L/min), then all draws shall be implemented at a flow rate equal 

to the rated maximum GPM. 

TABLE III.4—LOW-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 15.0 (56.8) 1.7 (6.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 1:00 1.0 (3.8) 1 (3.8) 

4 ........................................................................................................................... 10:30 6.0 (22.7) 1.7 (6.4) 

5 ........................................................................................................................... 11:30 4.0 (15.1) 1.7 (6.4) 

6 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

10 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

11 ......................................................................................................................... 17:00 3.0 (11.4) 1.7 (6.4) 

Total Volume Drawn Per Day: 38 gallons (144 L) 

* Denotes draws in first draw cluster. 

TABLE III.5—MEDIUM-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 15.0 (56.8) 1.7 (6.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 1:40 9.0 (34.1) 1.7 (6.4) 

4 ........................................................................................................................... 10:30 9.0 (34.1) 1.7 (6.4) 

5 ........................................................................................................................... 11:30 5.0 (18.9) 1.7 (6.4) 

6 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 16:00 1.0 (3.8) 1 (3.8) 


tkelley on DSK3SPTVN1PROD with RULES2
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40553 

12Healy WM, Lutz JD, and Lekov AB., 

‘‘Variability in Energy Factor Test Results for 

Residential Electric Water Heaters,’’ HVAC&R 

Research, Vol. 9, No. 4 (October 2003). 

TABLE III.5—MEDIUM-USAGE DRAW PATTERN—Continued 

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

10 ......................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

11 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

12 ......................................................................................................................... 17:00 7.0 (26.5) 1.7 (6.4) 

Total Volume Drawn Per Day: 55 gallons (208 L) 

* Denotes draws in first draw cluster. 

TABLE III.6—HIGH-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 27.0 (102) 3 (11.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 0:40 1.0 (3.8) 1 (3.8) 

4 * ......................................................................................................................... 1:40 9.0 (34.1) 1.7 (6.4) 

5 ........................................................................................................................... 10:30 15.0 (56.8) 3 (11.4) 

6 ........................................................................................................................... 11:30 5.0 (18.9) 1.7 (6.4) 

7 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

10 ......................................................................................................................... 16:00 2.0 (7.6) 1 (3.8) 

11 ......................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

12 ......................................................................................................................... 16:30 2.0 (7.6) 1.7 (6.4) 

13 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

14 ......................................................................................................................... 17:00 14.0 (53.0) 3 (11.4) 

Total Volume Drawn Per Day: 84 gallons (318 L) 

* Denotes draws in first draw cluster. 

D. Instrumentation 

In the November 2013 NOPR, DOE 

proposed to maintain the 

instrumentation installation 

requirements and piping configuration 

as currently specified in the residential 

water heater test procedure. 78 FR 

66202, 66217 (Nov. 4, 2013). For storage 

water heaters having a rated volume 

below 20 gallons, which are not covered 

in the existing DOE test method, DOE 

proposed that the average tank 

temperature be determined based on 

three temperature sensors located at the 

vertical midpoints of three sections of 

equal volume within the storage tank, as 

opposed to the currently required six 

sensors for storage water heaters having 

a rated volume above 20 gallons. Id. No 

comments were received opposing this 

approach, but AET requested that 

guidance should be provided regarding 

the unspecified horizontal lengths of 

pipe in the figures. (AET No. 58 at p. 20) 

For the final rule, DOE has modified 

Figures 1 through 4 of the test procedure 

to include those dimensions. 

DOE proposed in the November 2013 

NOPR to tighten the allowed accuracy 

on electric power and energy measuring 

equipment from the current value of ±1 

percent to ±0.5 percent. 78 FR 66202, 

66217 (Nov. 4, 2013). A study has 

shown the significant effect of the 

accuracy of the electric power 

measurements on the uncertainty in the 

overall energy factor.12 A similar change 

was made in ASHRAE 118.2–2006, 

‘‘Method of Testing for Rating 

Residential Water Heaters,’’ and DOE 

research confirms that equipment 

having this tolerance level is readily 

available. DOE also proposed in the 

November 2013 NOPR that, for mass 

measurements greater than or equal to 

10 pounds (4.5 kg), a scale that is 

accurate within ±0.5 percent of the 

reading must be used to make the 

measurement. Id. Lastly, DOE proposed 

that, for relative humidity 

measurements, a sensor that is accurate 

within ±1.5 percent of the reading be 

used to make the measurement. Id. at 

66220. No comments were received 

opposing these proposals, so DOE has 

incorporated these proposals into the 

final rule. 

DOE also proposed in the November 

2013 NOPR to modify the data 

acquisition rate of the inlet and outlet 

water temperature during draws. Id. at 

66217. Currently, for all water heaters 

except variable firing rate instantaneous 

water heaters, measurements of the inlet 

and outlet water temperature are taken 

at 5-second intervals starting 15 seconds 

after the draw commences. For 

instantaneous water heaters with a 

variable firing rate, inlet and outlet 

water temperature measurements are 

taken at 5-second intervals starting 5 

seconds after the draw commences. The 

test procedure amendments call for 

temperature data at the inlet and outlet 

temperature sensors to be recorded at 3- 

second intervals starting 5 seconds after 

commencement of the draw for all water 

heaters. Accordingly, DOE also 

proposed that the time constant of the 

instruments used to measure the inlet 

and outlet water temperatures be no 

greater than 2 seconds. DOE anticipates 

that this approach will better capture 

the energy impact of water heater 

startup and cycling. Id. at 66217. No 

comments were received opposing these 

measures, so DOE has incorporated 

these proposals into the final rule. 

E. Test Conditions 

1. Outlet Water Temperature 

The current residential water heater 

test procedure calls for the temperature 

of the tank to be set so that the average 

hot water temperature within the 

storage tank is at 135 °F ± 5 °F (57.2 °C 

± 2.8 °C). 10 CFR part 430, subpart B, 

appendix E, section 2.4. The set point 


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impacts the performance of various 

types of water heaters differently, so 

DOE reexamined in the proposed test 

procedure the set point specification 

and how it is determined. In the 

November 2013 NOPR, DOE proposed 

to use a measurement of the temperature 

of the delivered water, rather than mean 

tank temperature, for setting the 

temperature for storage-type water 

heaters, and also proposed that the set 

point temperature of all residential 

water heaters be reduced to 125 °F +/¥ 

5 °F (51.7 °C +/¥ 2.8 °C). 78 FR 66202, 

66219–20 (Nov. 4, 2013). This value was 

primarily selected based on data 

available in DOE’s analysis for the April 

2010 energy conservation standards 

final rule, which found that the average 

set point temperature for residential 

water heaters in the field is 124.2 °F 

(51.2 °C). Additionally, the recent 

compilation of field data across the 

United States and southern Ontario by 

LBNL (referenced above) found a 

median daily outlet water temperature 

of 122.7 °F (50.4 °C), which supports 

specifying a test set point temperature of 

125 °F. DOE proposed that this new 

value would apply to first-hour rating 

tests for storage water heaters, 

maximum flow rate tests for 

instantaneous water heaters, and energy 

factor tests for all water heaters. DOE 

also tentatively concluded that a set 

point of 125 °F in the test method would 

not result in safety concerns related to 

the growth of Legionella. Further, DOE 

noted that water heaters are commonly 

set to temperatures in the range of 

120 °F to 125 °F even though the current 

set point in the test method is 135 °F. 

78 FR 66202, 66219 (Nov. 4, 2013). 

DOE received five comments (AET, 

EEI, HTP, NEEA and NPCC, Joint 

Comment) in response to DOE’s outlet 

water temperature proposals in the 

November 2013 NOPR supporting the 

switch to a set point temperature of 

125 °F for the first-hour rating and 

maximum flow rate tests and the 24- 

hour simulated-use test. (AET, No. 58 at 

p. 5; EEI, No. 63 at p. 5; HTP, No. 59 

at pp. 1–3; NEEA and NPCC, No. 64 at 

p. 9; Joint Comment, No. 77 at pp. 6– 

7) Advocates for the 125 °F outlet water 

temperature argue that it is the most 

representative of actual use in the field 

and, thus, should be used to determine 

performance under representative 

conditions. Additionally, AET and HTP 

suggested that specifying an outlet water 

temperature, as opposed to a stored 

water temperature, is more appropriate 

for evaluating water heaters using 

certain controls that purposely keep the 

stored water temperature at a low value. 

(AET No. 58 at p. 1; HTP, No. 59 at p. 

3) DOE received five comments (AIM, 

AHRI, A.O. Smith, GE, and Giant) in 

favor of keeping the set point 

temperature at 135 °F for the first-hour 

rating test or increasing it for both the 

first-hour rating/maximum flow rate test 

and the 24-hour simulated-use test. 

(AIM, No. 72 at p. 3; AHRI, No. 75 at 

pp. 3–4; A.O. Smith, No. 62 at p. 2; GE, 

No. 78 at p. 1; Giant, No. 76 at pp. 2– 

3) Four of the commenters who opposed 

the decrease in set point (AHRI, A.O. 

Smith, GE, Giant) argue that the burden 

of reestablishing the draw pattern bin 

categories using first-hour rating and 

maximum GPM values under the lower 

set point is too great because the change 

in first-hour ratings will add additional 

uncertainty to the establishment of the 

bins. AIM argued that the set point 

temperature should be increased 

because when the temperature is 

decreased in the field, the water heater 

will see a boost in energy efficiency. 

Rheem acknowledged that many water 

heaters are operated at lower 

temperatures than the set point 

specified in the current DOE test 

procedure and suggested that the 24- 

hour simulated-use test and associated 

draws would be more representative at 

the 125 °F set point temperature. 

However, based on test data, Rheem 

argued that the changes to the first-hour 

rating values from the change in set 

point are too unpredictable to serve as 

a basis for determining the draw pattern 

bin categories and suggested that the 

first-hour rating test should continue to 

be performed at 135 °F, as is current 

practice. (Rheem, No. 69 at pp. 3, 5) 

DOE has carefully considered these 

comments and concludes that a 

delivered water temperature of 125 °F 

will be applied to first-hour rating tests 

for storage water heaters, maximum 

flow rate tests for flow-activated water 

heaters, and energy factor tests for all 

water heaters. DOE is required to 

establish test procedures that are 

representative of how a covered product 

would be used in the field, and based 

on the data discussed previously, DOE 

concludes that 125 °F is the most 

representative temperature for the 

United States market. DOE has 

determined that the test should be 

conducted at a typical operating 

temperature and should not penalize 

those units optimized for such typical 

conditions. Moreover, DOE has 

determined that conducting the 

simulated-use test at a different 

temperature from the delivery capacity 

tests would add an undue burden on 

manufacturers and would result in 

ratings that would not be representative 

of typical usage in the field. While 

maintaining the test temperature at the 

value currently used in the test 

procedure could eliminate one source of 

uncertainty in converting existing 

energy factors to new uniform energy 

factors, DOE has determined that this 

conversion is feasible and that the 

benefits of testing at a representative 

temperature outweigh the short-term 

challenges in converting existing 

ratings. 

In response to the concerns expressed 

by AHRI, A.O. Smith, GE, and Giant 

regarding uncertainties in converting 

first-hour ratings values obtained at 

135 °F to comparable values at 125 °F, 

DOE revisited the values that were used 

to place water heaters into bins for 

uniform energy factor testing. In the 

November 2013 NOPR, DOE based these 

breakpoint values on information 

present in the current plumbing code 

that indicate appropriate water heaters 

for various home configurations based 

on their first hour rating values obtained 

under the existing test procedure. 78 FR 

66202, 66214 (Nov. 4, 2013). 

Preliminary testing by DOE indicated 

that the first-hour ratings obtained 

under the new procedure were 

comparable to those obtained under the 

existing test procedure, so DOE 

proposed to maintain the breakpoints 

between bins despite the change in the 

conditions for the first-hour rating test. 

DOE requested data to demonstrate 

the effect of modifying the first-hour 

rating test conditions and received data 

from Rheem and Bradford White. 

(Rheem No. 69 at p. 3; Bradford White 

No. 61 at p. 8) Rheem presented actual 

first-hour rating values under both the 

current test and the proposed test, 

whereas Bradford White simply 

provided the percentage change in the 

first-hour rating between the two test 

procedures. Both data sets suggest an 

overall downward trend of first-hour 

rating under the proposed test 

procedure but that there is variability in 

the results. Based on these data and 

additional data collected by DOE, the 

Department concludes that numerous 

characteristics of a water heater affect 

the change in its first-hour rating 

obtained at 135 °F, as compared to that 

obtained at 125 °F. The uncertainty in 

how the ratings change, however, does 

not justify abandoning the 125 °F test 

temperature. Since DOE has determined 

that the most representative delivery 

temperature is 125 °F and no comments 

were received that refuted the method 

applied to obtain the first-hour rating at 

that temperature, DOE concludes that 

the first-hour rating test, as proposed, 

provides an appropriate measure of the 

delivery capacity of a water heater as 

would be observed in the field. 


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13 In the November 2013 NOPR, DOE proposed 

the following breakpoints for each size 

classification for testing at 125 °F. Point-of-use 

(since renamed ‘‘very small’’): < 20 gallons; low: 20 

<= FHR < 55 gallons; medium: 55 <= FHR < 80 

gallons; and high: >= 80 gallons. 78 FR 66202, 

66235 (Nov. 4, 2013). 

DOE maintains that the breakpoint 

values used to place water heaters into 

bins for uniform energy factor testing 

presented in the NOPR are appropriate 

for tests conducted at 135 °F, but 

acknowledges that some adjustments 

may be needed for tests conducted at 

125 °F since first-hour rating values may 

change at this temperature. To better 

account for the change in the first-hour 

rating procedure, DOE used the 

expanded set of available experimental 

data to reassess the proposed breakpoint 

values of first-hour ratings for placing 

water heaters into sizing bins for the 

simulated-use test. DOE examined 

different regressions using the data 

submitted by Rheem and those collected 

by the Department and found that the 

ratings at 125 °F and those at 135 °F 

could be modeled as functions of 

storage volume and the product of input 

rate and recovery efficiency. The 

recovery efficiency for data presented by 

Rheem was estimated based on the 

description of the water heater being 

tested. These regressions were then used 

to determine what breakpoint values 

would result in nearly the same 

classification for a particular water 

heater tested at 125 °F as it would have 

when tested at 135 °F, based on its 

storage volume, recovery efficiency, and 

input rate. Based on this analysis, DOE 

decreased the breakpoint values for each 

size classification for testing at 125 °F 

under the new test procedure, as 

compared to the breakpoint values 

proposed in the NOPR.13 The new limits 

of first-hour ratings (FHR) for each 

category are as follows: 

Very Small: FHR < 18 gallons 

Low: 18 <= FHR < 51 gallons 

Medium: 51 <= FHR < 75 gallons 

High: FHR >= 75 gallons 

For the first-hour rating test, DOE 

proposed in the November 2013 NOPR 

that draws would terminate when the 

outlet temperature drops 15 °F (8.3 °C) 

from its maximum outlet temperature 

during the draw, as opposed to the drop 

of 25 °F (13.9 °C) implemented in the 

current test procedure. This change 

would ensure that water delivered 

meets the nominal useful temperature of 

110 °F (43.3 °C). AET and AIM 

supported this proposal. (AET, No. 58 at 

p. 6; AIM, No. 72 at p. 1) AET suggested 

that water delivered at a temperature 

lower than the minimum useful 

temperature of 110 °F should not be 

counted in the first-hour rating test. 

AIM suggested that useful hot water 

delivered be measured separately from 

total water delivered. AET and AIM also 

suggested that water delivered below 

110 °F should not be counted as useful 

delivered hot water in the 24-hour 

simulated use test. (AET No. 58 at p. 7; 

AIM No. 72 at p.1) 

DOE concludes that the lower 

temperature limit of useful hot water at 

110 °F is appropriate for the first-hour 

rating test and establishes that draws 

during the test will terminate when the 

delivery temperature drops to 15 °F 

below the outlet water temperature 

(which is nominally 125 °F), resulting in 

a draw termination temperature of 

approximately 110 °F for draws during 

the first-hour test. For the simulated-use 

test, however, DOE does not restrict 

outlet water temperature to at or above 

110 °F. While it strongly considered the 

comments made by AET and AIM in 

this regard, in DOE’s view, the 

simulated-use test, which provides a 

measure of energy efficiency rather than 

delivery capability, is best conducted 

without regard to water outlet 

temperature. A standard cutoff 

temperature of 110 °F is necessary for 

the first-hour rating test in order to 

determine the appropriate draw pattern, 

but no minimum temperature is 

necessary to estimate energy efficiency. 

Although DOE has selected its draw 

patterns to ensure that a water heater 

can deliver hot water during all draws, 

DOE recognizes that there may be cases 

where water heaters on the lower end of 

the capacity limit in each bin deliver 

water at a lower temperature than a 

consumer might desire. In these cases, 

DOE believes that accounting for water 

delivered at temperatures below 110 °F 

would be representative of water heater 

energy performance in the field. DOE 

uses correction factors in the test 

procedure’s calculation routines to 

adjust the daily energy consumption to 

estimate energy consumption at a 

nominal outlet temperature of 125 °F 

since daily energy consumption will 

differ based on the outlet temperature of 

the water provided. 

As noted above, in addition to 

proposing to change the temperature 

setting at which the test occurs, DOE 

also proposed in the November 2013 

NOPR to change the methodology for 

setting the temperature of storage-type 

units to rely on outlet water temperature 

rather than mean tank temperature. For 

water heaters with a single thermostat, 

DOE proposed to specify a set point 

based on the outlet water temperature 

during a draw. For water heaters with 

multiple thermostats, DOE proposed to 

maintain the procedure currently 

prescribed in the residential water 

heater test method, which specifies the 

set point based on water temperature 

inside the tank. 78 FR 66202, 66219–20 

(Nov. 4, 2013). 

In response, DOE received three 

comments that supported the proposed 

approach for specifying the set point 

based on the temperature of delivered 

water for water heaters with a single 

thermostat in the tank. However these 

commenters argued that the same 

approach should be applied for water 

heaters with multiple thermostats. 

(AET, HTP, A.O. Smith) Specifically, 

AET and HTP cautioned that the 

terminology used in the NOPR that 

provides a procedure for water heaters 

with multiple ‘‘thermostats’’ could be 

problematic because some water heaters 

utilize multiple temperature sensors 

(i.e., thermostats) that are not available 

to the user for modifying the delivery 

temperature but that are instead 

installed to relay data to a single 

controller that determines whether or 

not to activate heating. (AET No. 58 at 

p. 2; HTP No. 59 at p. 3). AET and HTP 

both submitted recommendations for 

setting the temperature controllers on 

water heaters with multiple control 

points. (AET No. 58 at p. 14; HTP No. 

59 at p. 4) AET urged DOE to utilize the 

first-hour rating test to verify that the 

temperature controllers are set to their 

proper value. According to AET, the 

temperature controls on a unit with 

multiple controllers would be 

determined to be within their proper 

settings if all of the following conditions 

are met: (1) At least 50 percent of the 

water drawn during the first draw of the 

first-hour rating test was delivered at a 

temperature between 120 °F and 130 °F; 

(2) no water is delivered with a 

temperature above 130 °F during the 

first-hour rating test; and (3) the initial 

delivery temperature of second and 

subsequent draws of the first-hour rating 

test is between 120 °F and 130 °F. AET 

asserts that, if these three conditions are 

met, then the water heater has the 

correct set-point and the results from 

the temperature set-point test can be 

used to determine the first-hour rating. 

On this topic, HTP suggested a method 

that progressively disables the 

thermostats, and uses draws of onefourth of the total volume, taken after 

full recovery of each of the heat inputs 

being controlled by the active 

thermostats, to determine if the delivery 

temperature falls within the requisite 

125 °F +/¥ 5 °F range. If the water 

heater does not achieve the required 

delivery temperature within five 

iterations, the test laboratory would 

resort to the technique proposed in the 

NOPR. 


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DOE also received several comments 

opposed to the proposed approach. DOE 

received one comment (Rheem) that 

opposed the approach of specifying a set 

point for a water heater with a single 

thermostat in the tank based on outlet 

temperature, arguing that this method 

mischaracterizes the stored energy 

inside the tank. (Rheem No. 69 at p. 5) 

DOE does not agree with this claim 

since the stored energy inside the tank 

is measured in the proposed procedure 

in the same manner as is done in the 

current procedure and because setting 

the outlet temperature or stored water 

temperature is independent of the 

determination of stored energy. AHRI 

and Giant stated that they do not agree 

with the proposed method because ‘‘the 

method used when the model has more 

than one thermostat should follow the 

basic principles of the procedure for 

setting thermostats in the current test 

method.’’ (AHRI No. 75 at p.4; Giant No. 

76 at p.3) On the point raised by AHRI 

and Giant, DOE notes that the method 

for models with more than one 

thermostat proposed in the November 

2013 NOPR already matches the 

approach specified in the current test 

method. 

After careful consideration of the 

comments, DOE has decided to adopt 

several changes to the method to 

determine set point temperature for 

storage-type water heaters. First, in 

response to comments regarding the use 

of the terminology ‘‘thermostat,’’ DOE 

has changed the description from 

thermostat to ‘‘temperature controller’’ 

and has added a definition of 

temperature controller as ‘‘a device that 

is available to the user to adjust the 

temperature of the water inside a 

storage-type water heater or the outlet 

water temperature.’’ This change in 

terminology should eliminate any 

confusion on the part of the user of the 

test procedure between the useraccessible temperature controls and 

temperature sensors that are used in the 

water heater but may not be directly 

accessible to the user for making 

temperature adjustments. 

Second, DOE has decided to maintain 

its stated approach in the NOPR for 

setting the temperature for water heaters 

with a single temperature controller. In 

the final rule, DOE specifies that the set 

point be based on outlet water 

temperature. DOE determined that some 

water heaters would be disadvantaged 

by requiring an average tank 

temperature of 125 °F—due to 

stratification, a tank with an average 

temperature of 125 °F would deliver 

water at a temperature higher than 

125 °F. Such a setting could have an 

unrepresentative detrimental effect on 

efficiency compared to its intended 

operation in the field if the design of the 

water heating system relies on the 

average temperature of the stored water 

being at a lower temperature than the 

temperature of the water delivered to 

the user. 

Third, DOE incorporates the method 

suggested by AET to specify the set 

point of a water heater with multiple 

temperature controllers because it can 

be performed in conjunction with the 

first-hour rating test. However, DOE has 

modified one aspect of AET’s suggested 

method by allowing water delivered 

during a final draw of the first-hour 

rating test that begins at the end of the 

test to fall below 120 °F because the 

water heater may not have recovered 

fully when the final draw is initiated. 

This approach ensures proper 

temperature settings and will be less 

burdensome than the alternate 

technique proposed by HTP because it 

can be performed in conjunction with 

the first-hour rating test. 

Finally, DOE eliminates 

normalization of the daily water-heating 

energy consumption to a nominal stored 

water temperature, as provided in the 

current test procedure. DOE received 

two comments recommending that, 

because of the proposed technique to 

base the temperature setting of the water 

heater on the outlet water temperature, 

the test procedure should not normalize 

the energy consumption of any storage 

water heater to a nominal stored water 

temperature of 125 °F. (AET No. 58 at p. 

14; SMT No. 66 at p. 3) AET indicated 

that normalizing to a nominal stored 

water temperature penalizes advanced 

control technologies that manipulate 

storage temperature to reduce heat 

losses and improve performance. SMT 

commented that some water heater 

models are designed to operate with 

stratified tanks and that many utilize 

control algorithms that purposely 

manage the water temperature at the 

middle and lower levels differently from 

the top of the tank. DOE agrees with 

these comments. DOE is concerned that 

the temperature setting on the water 

heater could be lowered during the 

simulated-use test to an unrealistic 

value that would result in delivered 

water that is below a usable level. To 

avoid this situation, the final rule 

provides that the temperature control 

settings shall not be changed for the 

duration of the delivery capacity test 

and the simulated-use test once they are 

determined pursuant to the test 

procedure. Additionally, the final rule 

includes language that will allow a test 

laboratory to verify that the temperature 

settings are appropriate throughout the 

test by conducting a second 24-hour 

simulated-use test immediately after the 

test used to determine the uniform 

energy factor and with an identical draw 

pattern. If the average delivered 

temperature during this second 24-hour 

test is within the temperature bounds 

specified by the test procedure, then the 

temperature control scheme meets the 

requirements of the test procedure in 

providing the required outlet water 

temperature. 

2. Ambient Temperature and Relative 

Humidity 

The residential water heater test 

procedure requires that testing be 

performed in an environment with an 

ambient air temperature fixed at 67.5 °F 

± 2.5 °F (19.7 °C ± 1.4 °C). 10 CFR part 

430, subpart B, appendix E, section 2.2. 

For heat pump water heaters, however, 

the environmental conditions are more 

tightly constrained, with an ambient air 

temperature requirement of 67.5 °F ± 

1 °F (19.7 °C ± 0.6 °C) and a relative 

humidity requirement of 50 percent ± 1 

percent. Id. These specifications for heat 

pump water heaters reflect the fact that 

heat pump water heater energy use is 

highly dependent on the ambient 

temperature and relative humidity. 

Because water heaters are placed in a 

wide variety of locations within and 

outside of a home, and given the large 

impact of these factors on heat pump 

water heater efficiency, DOE considered 

potential revisions to the ambient air 

test conditions set forth in the DOE test 

procedure in order to assess whether the 

currently-specified conditions are 

representative of conditions typically 

encountered in residential installations. 

In the November 2013 NOPR, DOE 

proposed not to change the current 

ambient dry bulb temperature of 

between 65 °F and 70 °F when testing 

water heaters other than heat pump 

water heaters and at 67.5 °F ± 1 °F when 

testing heat pump water heaters. DOE 

also proposed to include the current 

relative humidity of 50 percent for heat 

pump water heaters, but to relax the 

tolerance to ± 2 percent relative 

humidity. DOE believes these 

conditions are representative of typical 

field conditions encountered by water 

heaters installed in the U.S. and has not 

found any data to justify changing these 

conditions. DOE proposed to relax the 

tolerance for relative humidity because 

research indicates that commonly-used, 

laboratory-grade relative humidity 

sensors have uncertainties on the order 

of 1 to 1.5 percent (78 FR 66202, 66220 

(Nov. 4, 2013)), and the tolerance cannot 

exceed the accuracy of the measuring 

equipment. It should be noted that the 

relative humidity can be obtained from 

measurements of dry bulb and wet bulb 


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temperatures and the determination of 

relative humidity through these 

temperature measurements would result 

in a measure of relative humidity with 

much lower uncertainty because dry 

bulb and wet bulb temperatures can be 

measured with high accuracy. However, 

most laboratories use relative humidity 

sensors that provide an accurate 

measurement of relative humidity 

through a less burdensome method. 

DOE received one comment from SMT 

suggesting that imposing the same dry 

bulb air temperature for all water 

heaters that is imposed for heat pump 

water heaters could eliminate the 

necessity of correcting the energy 

consumption for differences between 

the measured air temperature and the 

nominal temperature. (SMT No. 66 at 

p.3) DOE is not adopting this 

recommendation because it may 

necessitate significant changes in 

laboratory environmental conditioning 

equipment that would be very costly to 

manufacturers and testing laboratories. 

DOE believes the current method for 

accounting for ambient temperature 

allows for sufficiently accurate test 

results. 

Regarding heat pump water heaters, 

NEEA and NPCC urged DOE to require 

testing under a variety of conditions due 

to differing average temperature and 

humidity conditions found in the 

northern climates. (NEEA and NPCC, 

No. 64 at p. 10) HTP submitted a 

comment stating that heat pump water 

heaters should be tested at a range of 

ambient conditions due to their 

sensitivity to temperature and humidity. 

(HTP, No. 59 at pp. 6–7) The Joint 

Comment suggested a representative 

temperature of 50 °F ‘‘with 

appropriately high humidity levels,’’ 

thereby reflecting installations in cool 

basements and garages. (Joint Comment, 

No. 77 at p. 5) 

After carefully considering these 

comments, DOE has decided to 

maintain the current ambient dry bulb 

temperature of 67.5 °F ± 1 °F and adopt 

the proposed relative humidity of 50 

percent ± 2 percent for heat pump water 

heaters. DOE recognizes that regional 

differences in ambient dry bulb 

temperature and relative humidity exist 

and that these differences can have an 

effect on the efficiency of heat pump 

water heaters. However, DOE has 

determined that the conditions 

established in this final rule are 

representative of the country as a whole 

and that testing of heat pump water 

heaters at various temperature and 

humidity conditions is unnecessary to 

determine the efficiency under a 

representative set of conditions. DOE 

also notes that adding multiple rating 

points for heat pump water heaters 

would increase test burden 

significantly. 

3. Laboratory Airflow 

The existing test procedure specifies 

that the water heater shall be set up in 

an area that is protected from drafts. To 

clarify this statement, DOE proposed in 

the November 2013 NOPR to require 

that the area be protected from drafts of 

more than 50 ft/min (2.5 m/s). 78 FR 

66202, 66220 (Nov. 4, 2013). This value 

is in accordance with specifications in 

Canadian Standard 745–03, ‘‘Energy 

Efficiency of Electric Storage Tank 

Water Heaters and Heat Pump Water 

Heaters.’’ DOE did not receive any 

comments opposing this proposal, but 

the Department did receive one 

comment indicating that a typographical 

error was present in the NOPR’s 

conversion from ft/min to m/s. (A.O. 

Smith No. 62 at p. 5) DOE is adopting 

the provision in its corrected form, 

which requires that the area be 

protected from drafts of more than 50 ft/ 

min (0.25 m/s). 

F. Storage Tank Pre-Conditioning 

In the November 2013 NOPR, DOE 

tentatively concluded that initiating 

draw patterns on two consecutive days, 

with measurements only taking place 

during the second 24-hour period would 

lead to more consistent results since the 

state of the water heater at the beginning 

of the 24-hour test period on the second 

day will be similar to that at the end of 

that test period. 78 FR 66202, 66221 

(Nov. 4, 2013). Thus, DOE tentatively 

proposed to require storage water 

heaters to be pre-conditioned in this 

manner. 

DOE received ten comments in 

response to the November 2013 NOPR 

regarding the proposed water heater preconditioning requirements. AET and the 

Joint Comment stated there was no 

significant burden associated with a 24- 

hour simulated-use-test 

preconditioning. However, AHRI, A.O. 

Smith, Giant, HTP, NEEA and NPCC, 

Rheem, and SMT stated that there is a 

significant burden associated with this 

requirement. (AET, No. 58 at p. 12; 

AHRI, No. 75 at p. 3; A.O. Smith, No. 

62 at p. 3; Giant, No. 76 at p. 3; HTP, 

No. 59 at p. 2; NEEA and NPCC, No. 64 

at p. 4; Joint Comment, No. 77 at p. 6; 

Rheem, No. 69 at p. 4) Bradford White 

(referring to comments submitted by 

AHRI in response to the January 2013 

RFI that suggested the adoption of the 

pre-conditioning period proposed in the 

NOPR) commented that the AHRI 

comments were originally proposed in 

an effort to remove use of an internal 

tank temperature probe, which is no 

longer included in the test procedure. 

(Bradford White, No. 61 at p. 9) Eight 

commenters (AHRI, A.O. Smith, 

Bradford White, Giant, HTP, NEEA and 

NPCC, Joint Comment, Rheem) 

recommended continuing the use of the 

current preconditioning procedures. 

DOE notes that these commenters 

include AHRI, the commenter that 

originally suggested the 24-hour 

simulated-use-preconditioning. (AHRI, 

No. 75 at p. 3; A.O. Smith, No. 62 at p. 

3; Bradford White, No. 61 at p. 9; Giant, 

No. 76 at p. 3; HTP, No. 59 at p. 2; 

NEEA and NPCC, No. 64 at p. 4; Joint 

Comment, No. 77 at p. 6; Rheem, No. 69 

at p. 4) 

DOE has considered these comments 

and has determined that the added 

burden of mandating a 24-hour 

preconditioning as described above 

outweighs the potential benefits that 

could be provided by such an approach. 

However, DOE has determined that 

some specification of test preparation is 

needed to improve the reproducibility 

of the test results. First, DOE has found 

that a storage water heater must be 

maintained with its stored water at a 

temperature typically seen during 

normal operation for a period of time (a 

‘‘soak-in period’’) prior to the start of 

any test to ensure that the materials 

making up the water heater reach a 

relatively steady temperature. 

Comments from the December 2013 

Public Meeting indicated that such an 

approach is currently a best practice in 

testing water heaters and that this soakin period can be conducted while the 

water heater is not connected to a test 

apparatus. (Public Meeting Transcript, 

No. 81 at p. 82) This latter point reduces 

the need for an additional test apparatus 

to maintain the rate of testing that is 

currently achieved in laboratories and 

will, therefore, minimize the need to 

purchase additional test equipment to 

meet the requirements of the new test 

procedure. After a computational 

analysis of heat transfer through the 

walls of a storage water heater, DOE has 

determined that a soak-in period of at 

least 12 hours will minimize transient 

heat transfer effects. Therefore, DOE 

adopts a requirement that a storage 

water heater (including heat pump 

water heaters with storage volume) sit in 

an idle state (i.e., no water draws) with 

water stored in it for a minimum of 12 

hours following the end of recovery 

from a cold start prior to conducting 

either a first-hour rating test or a 

simulated-use test. 

Second, DOE has found that a water 

heater must not undergo a recovery 

immediately prior to the start of the 24- 

hour simulated-use test because the 

recovery will add significant 


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uncertainty to the critical measurement 

of average tank temperature at the start 

of the test. Consequently, DOE adopts a 

requirement that the 24-hour simulateduse test be preceded by at least a onehour period during which all heat 

sources to the water in the tank do not 

energize. DOE concludes that 

incorporating these requirements will 

help ensure reproducible test results 

without being unduly burdensome. 

G. Operational Mode Selection 

In the November 2013 NOPR, DOE 

noted that heat pump water heaters that 

have recently entered the market 

typically have multiple operational 

modes and that selection of the 

operational mode could impact the 

results of energy efficiency testing. 78 

FR 66202, 66234 (Nov. 4, 2013). As a 

result, DOE proposed that water heaters 

should be tested under the default or 

‘‘out-of-the-box’’ mode of operation 

when both obtaining the first-hour 

rating and determining the energy 

factor. In addition, DOE proposed 

several clarifications for testing of units 

with multiple operational modes but no 

default mode. The clarifications are 

consistent with guidance issued by DOE 

on June 12, 2012 (see: http:// 

www1.eere.energy.gov/guidance/

detail_search.aspx?

IDQuestion=623&pid=2&spid=1). DOE 

did not receive any comments related to 

this proposal in response to the 

November 2013 NOPR and adopts the 

proposed requirements without change. 

H. Annual Energy Consumption 

Calculation 

The annual energy consumption is 

calculated for residential water heaters 

in the existing test procedure based on 

the daily energy consumption 

multiplied by 365 days. As discussed in 

the November 2013 NOPR, AHRI 

submitted a letter to the FTC on 

September 16, 2013, pointing out that 

calculating the annual energy 

consumption based on the daily energy 

consumption can lead to differing 

annual energy consumption, and 

consequently, differing estimated yearly 

operating costs, for different water 

heater models with the same energy 

factor rating. 78 FR 66202, 66220–21 

(Nov. 4, 2013). AHRI provided an 

example of two water heaters with 

differing daily energy consumption 

values but with energy factor values that 

would round to the same value based on 

the DOE rounding requirements 

provided in 10 CFR 430.23(e). AHRI 

stated that having slightly different 

yearly operating cost estimates for two 

water heaters with the same efficiency 

rating can be confusing to consumers 

and somewhat misleading based on the 

accuracy of the test method. AHRI 

suggested revising the calculation of the 

annual energy consumption so that it is 

based on the energy factor rating. 

In the November 2013 NOPR, DOE 

proposed to adopt the calculation 

method suggested by AHRI for annual 

energy consumption, which is based on 

the nominal energy consumed during 

the test and the energy factor rating 

rather than the daily energy 

consumption. Id. at 66221. NEEA and 

NPCC strongly opposed any calculation 

of annual energy use for water heaters, 

arguing that the calculation of annual 

energy use is misleading in a large 

number of instances due to wide 

variations in annual household hot 

water use. (NEEA and NPCC, No. 64 at 

p. 16) 

Although DOE agrees with NEEA and 

NPCC that the actual annual energy 

consumption of water heaters can vary 

widely based on variations in field 

conditions, DOE believes that 

calculating an estimated annual energy 

consumption based on the results of the 

test procedure can provide consumers 

with valuable information for 

comparing two water heaters under a 

standard set of conditions (i.e., those 

conditions defined in the DOE test 

procedure). DOE believes that this 

additional metric can provide 

consumers who are unfamiliar with the 

uniform energy factor metric with a 

more familiar and easier-to-understand 

metric for comparing water heater 

performance. For this reason, DOE 

chooses to retain the calculation of 

annual energy consumption proposed in 

the November 2013 NOPR. 

I. Conversion of Existing Energy Factor 

Ratings 

AEMTCA amended EPCA to require 

that, along with developing a uniform 

descriptor, DOE must also develop a 

mathematical conversion factor to 

translate the results based upon use of 

the efficiency metric under the existing 

test procedure to the new uniform 

descriptor. (42 U.S.C. 6295(e)(5)(E)) 

AEMTCA provided that a manufacturer 

may apply the conversion factor to 

rerate existing models of covered water 

heaters manufactured prior to the 

effective date of the final rule 

establishing the uniform descriptor. 

Further, the conversion factor must not 

affect the minimum efficiency 

requirements for covered water heaters, 

and, as a result, would not lead to a 

change in measured energy efficiency 

for existing products. DOE interprets 

these requirements to mean that DOE 

must translate existing ratings from the 

current metrics to the new metric, while 

maintaining the stringency of the 

current standards. 

In response to the November 2013 

NOPR, DOE received three comments 

(AHRI, BWC, Joint Comment) regarding 

the conversion of existing ratings. 

(AHRI, No. 75 at p. 6–7; BWC, No. 61 

at p. 7; Joint Comment, No. 77 at p. 2) 

AHRI and BWC suggested water heater 

types to test and urged DOE to release 

a schedule and process for the 

development of the conversion factor as 

soon as possible. The Joint Comment 

suggested that the sensitivity of the 

energy factor to draw pattern should be 

investigated and that systematic 

differences between ‘‘old’’ and ‘‘new’’ 

values were expected for several 

technologies. 

DOE notes these comments regarding 

the conversion factor and will consider 

them fully once the test procedure is 

finalized to assist in developing the 

conversion factor. DOE plans to conduct 

a separate rulemaking to establish the 

conversion factor once the test method 

is finalized. DOE also plans to translate 

its current energy conservation 

standards to equivalent standards 

denominated in the new uniform 

efficiency metric in a separate 

rulemaking. Should it become apparent 

in the rulemaking to establish the 

conversion factor that changes may be 

required in the test procedure, DOE will 

address these issues at that time. 

J. Full Fuel Cycle 

In response to the November 2013 

NOPR, DOE received additional 

comments related to source-based 

metrics. EEI stated that, consistent with 

other Federal laws, any new descriptor 

or conversion factor should only be 

based on point-of-use metrics. (EEI, No. 

63 at p. 4) AGA and NPGA supported 

a metric based on the full fuel cycle that 

would provide a complete accounting of 

energy consumption from extraction, 

processing, and transportation of 

energy. (AGA, No. 68 at p. 1; NPGA, No. 

60 at p. 1) 

In the November 2013 NOPR, DOE 

responded in detail to similar concerns 

brought forth by stakeholders in 

response to the January 2013 RFI. In 

short, DOE reviewed the proposed water 

heater test procedure in relation to the 

Department’s newly established full fuel 

cycle (FFC) policy, and tentatively 

concluded that no substantive 

amendments are needed to the water 

heater test procedure to accommodate 

the FFC policy. 78 FR 66202, 66222 

(Nov. 4, 2013). However, for the 

purposes of representations, DOE 

tentatively concluded that some small 

improvements to the water heater test 

procedure are appropriate to 


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accommodate the FFC policy. DOE 

proposed in the November 2013 NOPR 

to define new terms in the test 

procedure to make it possible to 

quantify daily electric energy 

consumption separately from fossil fuel 

energy consumption and to add separate 

estimates of annual fossil fuel energy 

consumption and annual electrical 

energy consumption in addition to the 

overall annual energy consumption. 

This separation allows the user of the 

test procedure to estimate the 

operational cost of water heaters that 

use both fossil fuel and electricity based 

on the prices of those different energy 

sources. From a consumer’s perspective, 

annual operating cost is particularly 

useful for the products that have dual 

fuel inputs. DOE believes this consumer 

cost perspective is reasonably reflected 

in the FFC (i.e., the source/site factors 

recommended by the commenter are 

essentially numerically identical to the 

fuel cost ratios published biennially by 

the Secretary). 

In response to the November 2013 

NOPR, DOE received seven comments 

regarding the addition of terms to 

quantify daily electric energy 

consumption separately from fossil fuel 

energy consumption and adding 

separate estimates of annual fossil fuel 

energy consumption and annual 

electrical energy consumption in 

addition to the overall annual energy 

consumption. Four commenters 

supported the addition of these terms 

(AET, AIM, Joint Comment, NPGA), 

while three commenters did not (EEI, 

HTP, AHRI). (AET, No. 58 at p. 15; AIM, 

No. 74 at p. 1; EEI, No. 63 at p. 4; HTP, 

No. 59 at p. 5; Joint Comment, No. 77 

at p. 7; NPGA, No. 60 at p. 1–2; AHRI 

No. 80 at p. 2) EEI stated that it is not 

clear whether a separation by fuel type 

will be meaningful to the customer; HTP 

and AHRI argued that these terms are 

unnecessary. 

After considering these comments, 

DOE has decided to include terms to 

quantify daily electric energy 

consumption separately from fossil fuel 

energy consumption and to add separate 

estimates of annual fossil fuel energy 

consumption and annual electrical 

energy consumption (in addition to the 

overall annual energy consumption). 

DOE believes these added terms will 

provide consumers with more accurate 

information for comparing various water 

heating technologies without 

significantly adding to the overall test 

burden. 

K. Certification, Compliance, and 

Enforcement Issues 

1. Storage Volume Requirements 

In the November 2013 NOPR, DOE 

proposed to make several changes to its 

certification, compliance, and 

enforcement regulations at 10 CFR part 

429. First, DOE proposed to add 

requirements to 10 CFR 429.17 that the 

rated value of storage tank volume must 

equal the mean of the measured storage 

volumes of the units in the sample. 78 

FR 66202, 66223 (Nov. 4, 2013). DOE 

notes that there are currently no 

requirements from the Department 

limiting the allowable difference 

between the tested (i.e., measured) 

storage volume and the ‘‘rated’’ storage 

volume that is specified by the 

manufacturer. DOE has tested 65 

residential storage-type water heaters, 

including 44 gas-fired water heaters, 19 

electric water heaters, and 2 oil-fired 

water heaters. Through this testing, DOE 

has found that water heaters are 

consistently rated at storage volumes 

above their measured storage volume. 

For gas-fired water heaters, the rated 

volume ranged from 1.5 percent to 15.6 

percent above the measured volume, 

with the mean being 4.8 percent. For 

electric water heaters, the rated volume 

ranged from 5.0 to 10.6 percent above 

the measured volume, with the mean 

being 9.4 percent. DOE notes that its 

minimum energy conservation 

standards are based on the rated storage 

volume and decrease as rated storage 

volume increases. DOE believes 

consumers often look to storage volume 

as a key factor in choosing a storage 

water heater. Consequently, DOE 

proposed to adopt requirements that the 

rated value must be the mean of the 

measured values. In addition, DOE 

proposed to specify that for DOEinitiated testing, the measured storage 

volume must be within five percent of 

the rated volume in order to use the 

rated storage volume in downstream 

calculations. Id. If the measured storage 

volume is more than five percent 

different than the rated value, then DOE 

proposed to use the measured value in 

downstream calculations. DOE 

proposed to specify similar 

requirements for residential-duty 

commercial water heaters. 

AHRI, A.O. Smith, Bradford White, 

HTP, the Joint Comment, and Rheem 

opposed the proposal to require that the 

rated storage value be the mean of the 

measured values. (AHRI, No. 75 at p. 4; 

A.O. Smith, No. 62 at p. 3; Bradford 

White, No. 61 at p. 10; HTP, No. 59 at 

p. 8; Joint Comment, No. 77 at p. 3; 

Rheem, No. 69 at p. 6) AHRI argued that 

the proposal is unnecessary and not an 

efficiency-related matter, but a safety 

matter. As such, AHRI argued that it is 

outside the scope of the DOE’s authority 

and has been adequately addressed in 

ANSI Z21 and the UL standards for 

water heaters. AHRI stated that there are 

currently no units on the market that 

would allow the difference between 

rated and measured volume to dodge 

the minimum efficiency standards. A.O. 

Smith and Bradford White noted that 

adding this requirement would make a 

water heater which was legal under the 

old test procedure illegal, which in turn 

would necessitate updating the 

minimum efficiency standards. HTP 

stated that the five-percent tolerance on 

the measured storage volume as 

compared to rated storage volume is too 

stringent and would impose a 

significant re-design burden upon 

manufacturers. HTP instead suggests a 

ten-percent tolerance to reduce the 

manufacturer’s burden. 

After carefully considering these 

comments, DOE has decided to require 

that the rated storage volume be based 

on the mean of the measured values. 

The efficiency of a water heater is 

clearly related to the rated storage 

volume and, therefore, within DOE’s 

authority to regulate. DOE seeks to 

eliminate any potential incentives for 

manufacturers to continue the current 

practice of exaggerating the storage 

volume of water heaters currently on the 

market by inflating the rated volume as 

compared to the actual measured 

volume. While DOE acknowledges 

AHRI’s assessment that no current water 

heaters on the market could evade 

minimum efficiency standards, this 

does not rule out the possibility that 

future water heaters could do so; the 

revised approach adopted in this final 

rule addresses this concern going 

forward. Regarding the comment from 

A.O. Smith and Bradford White that 

adding this requirement would make a 

water heater which was legal under the 

old test procedure illegal, DOE notes 

that if AHRI’s comment about the 

current water heater market is correct, 

the difference between rated and 

measured volume should not cause any 

water heaters to be subject to different 

energy conservation standards, thereby 

rendering such concerns theoretical. 

Furthermore, there will be a 

mathematical conversion for water 

heater models that are currently 

compliant to transition from results 

generated under the old test procedure 

to the new test procedure. Additionally, 

DOE-initiated testing will require that 

all measured storage volumes be within 

±5 percent of the rated storage volume 

to be considered valid. DOE agrees with 


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HTP that the 5 percent tolerance will 

result in manufacturers having to rerate 

certain models at an additional burden. 

However, DOE has concluded that any 

tolerance greater than 5 percent will not 

have the desired effect of harmonizing 

rated and measured storage volume 

values, and it is likely that a significant 

gap would persist between the values if 

a larger tolerance were adopted. If an 

invalid storage volume is found, the 

measured storage volume will be used 

in determining the applicable minimum 

energy conservation standard and 

calculations within the test procedure. 

2. First-Hour Rating and Maximum GPM 

Requirements 

Because the first-hour and maximum 

GPM ratings will determine the 

applicable draw pattern for use during 

the uniform energy factor test, DOE 

proposed in the November 2013 NOPR 

to include rating requirements for those 

values. 78 FR 66202, 66223 (Nov. 4, 

2013). DOE proposed that the first-hour 

rating or maximum GPM rating, as 

applicable, must be the mean of the 

measured values of the sample used for 

certifying the basic model’s efficiency. 

For DOE testing, the rated value will be 

considered valid if it is within five 

percent of the measured value. In such 

a case, DOE proposed that the rated 

value would be used for the purposes of 

choosing the appropriate draw pattern 

for the uniform energy factor test. In the 

case of an invalid rating (i.e., the firsthour rating or maximum GPM rating is 

more than five percent different from 

the measured value), DOE proposed to 

use the measured value to determine the 

applicable draw pattern for the uniform 

energy factor test. DOE did not receive 

any comments objecting to these 

proposals, and, thus, DOE is adopting 

them in this final rule. 

3. Ratings for Untested Models 

In reviewing the current test 

procedure, DOE has concluded that 10 

CFR part 430, subpart B, appendix E, 

section 7.0, ‘‘Ratings for Untested 

Models,’’ is more appropriately 

addressed in 10 CFR part 429, which 

deals with requirements for certification 

of residential water heaters, than in the 

test procedure. In the November 2013 

NOPR, DOE proposed to remove this 

section from Appendix E and place a 

similar section in 10 CFR 429.17. 78 FR 

66202, 66223–24 (Nov. 4, 2013). DOE 

proposed to maintain the same 

requirements for gas water heaters in 10 

CFR 429.17 that were previously in 

section 7.0, which allow units using 

propane gas that have an input rating 

within 10 percent of an otherwise 

identical natural gas unit to use the 

rating for the natural gas unit in lieu of 

separate testing. DOE did not receive 

any comments related to this proposal, 

and thus, DOE adopts it in this final 

rule; however, DOE has moved the 

provision to 10 CFR 429.70 to reflect 

that this is an alternative method of 

determining efficiency (in lieu of 

testing). 

DOE also proposed to eliminate the 

provisions for electric water heaters that 

currently allow a manufacturer of 

electric water heaters that are identical 

except with different input ratings to 

designate a standard input rating at 

which to test the water heater. 78 FR 

66202, 66224 (Nov. 4, 2013). Under the 

current procedure, the manufacturer of 

electric water heaters may designate the 

standard input rating that would apply 

to all models that are identical with the 

exception of the power input to the 

heating element and test only at a single 

standard input rating. It also provides 

instructions for specifying the first-hour 

rating of units with higher and lower 

input ratings than the standard rating. 

The procedure also provides that the 

energy factor can be assumed to be the 

same across all input ratings. As noted 

above, DOE proposed to remove these 

provisions due to the proposed 

revisions in the test method for the firsthour rating and energy factor tests. The 

first-hour rating would be expected to 

vary based on the power input to the 

electric heating element. Under the 

revised test procedure, the applicable 

draw pattern for the uniform energy 

factor test is based on the first-hour 

rating. Thus, the first-hour rating must 

be accurate for the tested model to 

ensure accurate test results for the 

uniform energy factor test. 

In response to the November 2013 

NOPR, DOE received five comments 

(AHRI, BWC, Giant, Joint Comment, 

Rheem) opposing the proposal to 

remove the manufacturer’s ability to 

designate electric water heaters that are 

identical except for their respective 

input ratings as having a standard input, 

and one comment was received from 

HTP suggesting alternate methods of 

testing the units with different input 

ratings. (AHRI, No. 75 at p. 7; BWC, No. 

61 at p. 10–11; Giant, No. 76 at p. 3–4; 

HTP, No. 79 at p. 1–6; Joint Comment, 

No. 77 at p. 7; Rheem, No. 69 at p. 7). 

The five opposing comments stated that 

there would be a significant undue test 

burden associated with testing each 

model with a different input rating. Id. 

AHRI and Giant stated that the only case 

where a different input rating might be 

a concern is if the change in input rating 

results in a lower first-hour rating such 

that the unit would be tested under a 

different draw pattern than the unit 

with a ‘‘standard’’ input rating. (AHRI, 

No. 75 at p. 7; Giant, No. 76 at p. 3–4). 

DOE agrees that removing the 

provisions for rating electric water 

heaters with different input ratings 

could cause significant additional test 

burden for manufacturers. Thus, DOE is 

adopting the following requirements, 

which are roughly based on the method 

recommended by HTP to lessen burden 

while still ensuring that the ratings are 

representative of a model’s efficiency 

and capacity. DOE is adopting 

provisions in 10 CFR 429.70 that will 

allow manufacturers to use the firsthour rating and uniform energy factor 

determined by testing one basic model 

to rate other basic models, in certain, 

limited circumstances. Untested basic 

models with input ratings higher than 

the rating of the tested basic model can 

be assumed to have the same first-hour 

rating and uniform energy factor and 

may be rated as such. For untested basic 

models that only differ from the tested 

basic model in that they contain heating 

elements with input ratings below the 

tested basic model, the untested basic 

model with the lowest input rating for 

all heating elements must be tested for 

first-hour rating. If that untested basic 

model has a first-hour rating that would 

group it in the same draw pattern bin as 

the tested basic model, then all basic 

models with lower input ratings than 

the tested basic model may be assumed 

to have the same uniform energy factor 

as the tested basic model. These 

untested basic models can be assigned 

a first-hour rating equivalent to the 

volume removed in the first draw of the 

first-hour rating test of the tested basic 

model of electric water heater. However, 

if the unit with the lowest input rating 

has a first-hour rating that would result 

in classification in a draw pattern with 

a lower total volume drawn per day for 

the simulated-use test, the unit must be 

tested according to that lower draw 

pattern. At this point, the manufacturer 

may choose to test a second basic model 

that would represent water heaters in 

the lower sizing bin and apply the same 

principles noted above to determine the 

uniform energy factor and first-hour 

rating. 

DOE notes that the alternative 

efficiency determination method 

(AEDM) provisions for these consumer 

water heaters and residential-duty 

commercial water heaters are quite 

different from AEDM provisions for 

other types of covered products and 

equipment for which use of an AEDM 

is authorized. Specifically, these AEDM 

provisions do not permit any type of 

modeling or calculations of efficiency; 

they only permit use of a rating 

determined by testing to be used for 


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Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40561 

other basic models that meet certain 

criteria. In addition, DOE notes that the 

tested basic model will be indicated in 

a certification report with the number of 

units tested, while the untested basic 

models will be indicated in a 

certification report as having been 

certified using an AEDM. 

L. Reference Standards 

DOE’s test procedure for residential 

water heaters currently references two 

industry standards: (1) American 

Society for Testing and Measurement 

(ASTM) D2156–80, ‘‘Smoke Density in 

Flue Gases from Burning Distillate 

Fuels, Test Method for’’ and (2) 

ASHRAE Standard 41.1–1986, 

‘‘Standard Measurement Guide: Section 

on Temperature Measurements.’’ 

DOE retains these references in the 

uniform efficiency descriptor test 

method, but updates the referenced 

standards to the most recent versions: 

(1) ASTM D2156–09, ‘‘Standard Test 

Method for Smoke Density in Flue 

Gases from Burning Distillate Fuels’’ 

and (2) ASHRAE Standard 41.1–1986 

(RA2006), ‘‘Standard Method for 

Temperature Measurement.’’ For the 

November 2013 NOPR, DOE reviewed 

both of the updated standards and 

concluded that their adoption would 

not substantially impact the revised test 

method. 78 FR 66202, 66224 (Nov. 4, 

2013). DOE did not receive any 

comments on this issue in response to 

the NOPR, and consequently, DOE 

incorporates these industry standards by 

reference into DOE’s regulations for the 

water heaters test procedure. 

M. Compliance With Other EPCA 

Requirements 

As mentioned above, in amending a 

test procedure, EPCA directs DOE to 

determine to what extent, if any, the test 

procedure would alter the measured 

energy efficiency or measured energy 

use of a covered product. (42 U.S.C. 

6293(e)(1)) If the amended test 

procedure alters the measured energy 

efficiency or measured energy use, the 

Secretary must amend the applicable 

energy conservation standard to the 

extent the amended test procedure 

changes the energy efficiency of 

products that minimally comply with 

the existing standard. (42 U.S.C. 

6293(e)(2)) The current energy 

conservation standards for residential 

water heaters are based on energy factor, 

and the energy conservation standards 

for commercial water heaters are based 

on thermal efficiency and standby loss. 

DOE believes that the conversion factor 

(or factors) required by AEMTCA (as 

discussed in section III.I) and developed 

in a subsequent rulemaking will ensure 

that there is no change in measured 

energy efficiency. 

Consistent with 42 U.S.C. 6293(c), 

DOE typically requires that any 

representations of energy consumption 

of covered products must be based on 

any final amended test procedures 180 

days after the publication of the test 

procedure final rule. However, in this 

instance, the statute specifically 

provides for an effective date of the test 

procedure final rule which is one year 

after the date of the publication of the 

final rule. (42 U.S.C. 6295(e)(5)(D)(ii)) In 

addition, AEMTCA provides for the use 

of a conversion factor that will apply 

beginning on the date of publication of 

the conversion factor in the Federal 

Register and ending on the later of one 

year after the date of publication of the 

conversion factor or December 31, 2015. 

(42 U.S.C. 6295(e)(5)(E)(v)) Thus, the 

test procedure final rule will become 

effective one year after its publication, 

and manufacturers may at their 

discretion make representations of 

energy efficiency based either (a) on the 

final amended test procedures or (b) on 

the previous test procedures after 

applying the conversion factor until 

such time as use of the amended test 

procedure is required. The current test 

procedures for residential water heaters 

are set forth at 10 CFR part 430, subpart 

B, appendix E as contained in 10 CFR 

parts 200 to 499 edition revised as of 

January 1, 2014. The current test 

procedures for commercial water 

heating equipment are set forth at 10 

CFR 431.106 as contained in 10 CFR 

parts 200 to 499 edition revised as of 

January 1, 2014. As required by 

AEMTCA, the conversion factor may be 

used until the later of one year after the 

publication of the factor, or December 

31, 2015, after which time all testing 

must be conducted in accordance with 

the new amended test procedure. (Note, 

in this final rule, DOE provides that the 

conversion factor may be used until 

December 31, 2015, but DOE will amend 

that date, if necessary, upon publication 

of the conversion factor final rule.) DOE 

notes that during the interim period, 

manufacturers must use the same 

version of the test procedure for all 

representations of energy efficiency, 

including certifications of compliance. 

N. Other Issues 

At the December 6, 2013 public 

meeting, AIM and EEI requested 

clarification on the applicability of the 

first-hour rating and maximum GPM test 

for water heaters that may have a storage 

volume above 2 gallons but which also 

have heating elements or burners that 

are designed to deliver a continuous 

flow of hot water. (Public transcript, p. 

80–81, 84–86, 121–122) After 

considering these comments, DOE 

acknowledges that it may be possible to 

improve the test procedure’s 

specifications as to which tests must be 

conducted on each water heater, so the 

Department is clarifying the proper 

implementation of the applicable tests 

as part of this final rule. 

The proposed test procedure stated 

that storage water heaters should be 

tested to obtain a first-hour rating and 

that instantaneous water heaters be 

tested to obtain a maximum GPM rating. 

78 FR 66202, 66234–36 (Nov. 4, 2013). 

As noted by AIM, ‘‘flow-dominated’’ or 

‘‘heat-on-demand’’ water heaters exist 

that have very large burners but have 

some storage volume as a buffer. (AIM 

No. 70 at p. 2) DOE believes that the 

delivery capacity of such water heaters 

is best captured by a maximum GPM 

rating and is, thus, requiring water 

heaters with a heating input that is 

activated by the flow of water through 

them to be tested according to the 

maximum GPM test procedure 

regardless of storage volume. For all 

other storage water heaters, the firsthour rating test is to be applied to 

determine delivery capacity. DOE is 

using the term ‘‘flow-activated’’ in this 

final rule and is adding a definition for 

that term in the test procedure that is 

consistent with the definition of 

‘‘instantaneous water heater’’ currently 

at 10 CFR 430.2. 

For determining the uniform energy 

factor, DOE believes that any water 

heater with a storage volume greater 

than or equal to 2 gallons must be tested 

to account for the storage volume, even 

if they meet EPCA’s definition of an 

instantaneous water heater, which does 

not limit the stored volume. (42 U.S.C. 

6291(27)(B)) The reason for this 

determination is that changes in the 

stored energy in the water heater and 

variations in the heat loss from the 

water heater to the ambient can affect 

the uniform energy factor, and the test 

procedure proposed for storage water 

heaters captures these effects while that 

for instantaneous water heaters does 

not. While it might be possible to 

include such terms in the proposed test 

procedure for instantaneous water 

heaters, such a step would add no 

benefit for instantaneous water heaters 

with minimal storage volume and could 

be considered as adding an undue 

burden to the testing of those units. 

Therefore, DOE clarifies the 

applicability of the simulated-use test 

based on rated storage volume instead of 

by the terminology of ‘‘storage’’ versus 

‘‘instantaneous’’ in section 5 of 

appendix E. 


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DOE also clarifies the determination 

of the UA value to account for situations 

where the maximum tank temperature is 

achieved immediately following the 

recovery following the first draw 

cluster. As noted above, test data 

suggest that starting the standby period 

immediately following a recovery can 

lead to erroneous results due to the 

challenges in determining the average 

stored water temperature at that time. 

DOE has adjusted the start of the period 

used to determine the UA so that it must 

begin no less than five minutes 

following the end of the first recovery 

following the first draw cluster. 

IV. Procedural Issues and Regulatory 

Review 

A. Review Under Executive Order 12866 

The Office of Management and Budget 

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 (OMB). 

B. Review Under the Regulatory 

Flexibility Act 

The Regulatory Flexibility Act (5 

U.S.C. 601 et seq., as amended by the 

Small Business Regulatory Enforcement 

Fairness Act of 1996) requires 

preparation of an initial regulatory 

flexibility analysis (IFRA) for any rule 

that by law must be proposed for public 

comment and a final regulatory 

flexibility analysis (FRFA) for any such 

rule that an agency adopts as a final 

rule, unless the agency certifies that the 

rule, if promulgated, will not have a 

significant economic impact on a 

substantial number of small entities. A 

regulatory flexibility analysis examines 

the impact of the rule on small entities 

and considers alternative ways of 

reducing negative effects. Also, 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 final rule prescribes test 

procedure amendments used to 

determine compliance with energy 

conservation standards for residential 

water heaters and certain commercial 

water heaters. For residential water 

heaters and certain commercial water 

heaters, the amendments establish a 

uniform efficiency descriptor which is 

more representative of conditions 

encountered in the field (including 

modifications to both the test conditions 

and the draw patterns), and expand the 

scope of the test procedure to apply to 

certain residential water heaters and 

certain commercial water heaters that 

are currently not covered by the test 

procedure. DOE reviewed this final 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. The SBA size 

standards, listed by North American 

Industry Classification System (NAICS) 

code and industry description, are 

codified at 13 CFR part 121 and are 

available at http://www.sba.gov/content/ 

table-small-business-size-standards. 

Residential water heater manufacturing 

is classified under NAICS 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 heaters are 

classified under NAICS 333318—‘‘Other 

Commercial and Service Industry 

Machinery Manufacturing,’’ for which 

SBA also sets a size threshold of 1,000 

employees or fewer for being considered 

a small business. 

DOE has identified 19 manufacturers 

of residential 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’’ water heaters that 

can be considered small businesses. Six 

of the ‘‘residential-duty’’ water heater 

manufacturers also manufacture 

residential 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 final rule 

would not have a significant economic 

impact on any manufacturer, including 

small manufacturers. 

For residential water heaters, the 

amendments adopted in this final rule 

apply primarily to the draw pattern and 

outlet water temperature. Under DOE’s 

existing test procedure, manufacturers 

must perform a simulated-use test 

consisting of 6 draws of equal lengths 

with a water heater delivery 

temperature of 135 °F. This final rule 

will require manufacturers to perform a 

simulated-use test consisting of 9 to 14 

draws of varied length, depending on 

the capacity of the water heater, at an 

outlet water temperature of 125 °F. The 

change in outlet water temperature 

requires no additional effort or expense 

for the manufacturer, because 

establishing the test temperature is 

simply a matter of choosing the 

appropriate setting on the water heater. 

Likewise, the change in the number of 

draws would also result in very little 

burden on manufacturers. The length 

and timing of draws for the existing test 

procedure are largely controlled 

automatically by computer control. The 

changes will likely result in 

manufacturers having to reprogram the 

computer test programs to account for 

the new draw patterns. DOE estimates 

that this effort would take 

approximately one week to program and 

confirm operation of the amended test. 

It is estimated that approximately two 

days of a programmer’s time would be 

needed at a cost of $1,000, including 

overhead and benefits. This one-time 

cost is comparable to that charged by a 

third-party test laboratory for a single 

test, so it is not considered burdensome 

for water heater manufacturers. Since 

the simulated-use test takes 24 hours 

under both the existing and new test 

method, the length of the test would not 

change. The new test method does 

specify a 12-hour soak-in period prior to 

the 24-hour test for storage water 

heaters, however, which would add to 

the time required to conduct the test. 

This extra test time would not require 

extra personnel and would not 

necessitate the development of 

additional test platforms. DOE 

understands that a preconditioning 

period is already implemented by 

manufacturers as a best practice to allow 

the water heater to achieve operational 

temperature, so the added burden from 

the 12-hour soak-in would be minimal. 

In addition, these tests can be 


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conducted in the same facilities used for 

the current energy testing of these 

products, so there would be no 

additional facility costs required by the 

final rule. 

Lastly, the only potential 

instrumentation upgrade required to 

conduct the test would be electric 

power and energy measuring equipment 

that meets the accuracy levels that have 

changed from ± 1 percent to ± 0.5 

percent. DOE believes that equipment 

meeting these tolerances is already the 

industry standard. Purchase of a new 

instrument, if needed, would be 

expected to cost approximately $1,000. 

For certain commercial water heaters 

included in the scope of this 

rulemaking, the efficiency test required 

for equipment would change from the 

thermal efficiency and standby loss tests 

specified in the current DOE test 

method, to the simulated-use test for 

uniform energy factor in this final rule. 

The uniform energy factor test is 

inherently more complex than the 

thermal efficiency and standby loss 

tests, and, thus, it may be more difficult 

to implement. However, the standby 

loss test takes a significant amount of 

time, which is comparable to the 24- 

hour simulated-use test. Accordingly, 

overall testing time should remain fairly 

constant. DOE understands that the 

complexity of the uniform energy factor 

test would impose additional costs on 

manufacturers due to the need to 

automate draw patterns, as compared to 

the thermal efficiency test. In addition, 

some hardware purchases may be 

needed to allow for computer-controlled 

draws of hot water that are required in 

a simulated use test. However, DOE 

notes that many commercial water 

heater manufacturers also manufacture 

residential water heaters, and may 

already have this equipment from 

testing of residential units. Nonetheless, 

DOE estimates that this hardware could 

cost approximately $1,000, assuming 

that the laboratory already has a 

computer-controlled data acquisition 

system to collect data during the 

thermal efficiency and standby loss tests 

currently required. DOE estimates the 

costs for a programmer to create a 

computer program that automatically 

controls the hot water draws would be 

similar to the costs above, but that the 

time required may be slightly longer if 

the program is being developed from 

scratch. Under such circumstances, DOE 

estimates that 5 days of programmer 

time would be needed for a cost of 

$2,500, including overhead and 

benefits. 

Lastly, DOE considered the impacts 

on small businesses that manufacture 

residential water heaters that fall into 

categories that were previously not 

covered by the DOE residential water 

heater test procedure (e.g., models with 

storage volumes between 2 and 20 

gallons). In reviewing the market for 

these products, DOE did not identify 

any manufacturers that did not also 

manufacture other types of water 

heating equipment. Thus, DOE believes 

that these manufacturers would already 

have the needed equipment and 

computer programs to conduct the 

current DOE test. For the reasons stated 

previously, DOE does not believe the 

updates will cause significant additional 

burdens for these manufacturers. 

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 has provided 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 all 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 the test 

procedure on the date that compliance 

is required. DOE has established 

regulations for the certification and 

recordkeeping requirements for all 

covered consumer products and 

commercial equipment, including 

residential and commercial water 

heaters. 76 FR 12422 (March 7, 2011). 

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 20 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 final rule, DOE amends its test 

procedure for residential and 

commercial water heaters. 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 rule amends an 

existing rule without affecting the 

amount, quality or distribution of 

energy usage, and, therefore, will 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 

examined this final rule and determined 

that it will not have a substantial direct 

effect on the States, on the relationship 

between the national government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government. EPCA 

governs and prescribes Federal 

preemption of State regulations as to 

energy conservation for the products 

that are the subject of this final rule. 

States can petition DOE for exemption 

from such preemption to the extent, and 

based on criteria, set forth in EPCA. (42 

U.S.C. 6297(d)) No further action is 

required by Executive Order 13132. 


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40564 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

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, this final rule 

meets the relevant standards of 

Executive Order 12988. 

G. Review Under the Unfunded 

Mandates Reform Act of 1995 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA) requires 

each Federal agency to assess the effects 

of Federal regulatory actions on State, 

local, and Tribal governments and the 

private sector. Pub. L. 104–4, sec. 201 

(codified at 2 U.S.C. 1531). For a 

regulatory action resulting in a rule that 

may cause the expenditure by State, 

local, and Tribal governments, in the 

aggregate, or by the private sector of 

$100 million or more in any one year 

(adjusted annually for inflation), section 

202 of UMRA requires a Federal agency 

to publish a written statement that 

estimates the resulting costs, benefits, 

and other effects on the national 

economy. (2 U.S.C. 1532(a), (b)) The 

UMRA also requires a Federal agency to 

develop an effective process to permit 

timely input by elected officers of State, 

local, and Tribal governments on a 

‘‘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 final rule according to UMRA and 

its statement of policy and has 

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 

final rule will not have any impact on 

the autonomy or integrity of the family 

as an institution. Accordingly, DOE has 

concluded that it is not necessary to 

prepare a Family Policymaking 

Assessment. 

I. Review Under Executive Order 12630 

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 

will not result in any takings that might 

require compensation under the Fifth 

Amendment to the U.S. Constitution. 

J. Review Under Treasury and General 

Government Appropriations Act, 2001 

Section 515 of the Treasury and 

General Government Appropriations 

Act, 2001 (44 U.S.C. 3516 note) provides 

for agencies to review most 

disseminations of information to the 

public under 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 final rule under the OMB 

and DOE guidelines and has concluded 

that it is consistent with applicable 

policies in those guidelines. 

K. Review Under Executive Order 13211 

Executive Order 13211, ‘‘Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use,’’ 66 FR 28355 (May 

22, 2001), requires Federal agencies to 

prepare and submit to OIRA at OMB, a 

Statement of Energy Effects for any 

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 significant energy 

action, the agency must give a detailed 

statement of any adverse effects on 

energy supply, distribution, or use if the 

regulation is implemented, and of 

reasonable alternatives to the action and 

their expected benefits on energy 

supply, distribution, and use. 

This regulatory action to amend the 

test procedure for measuring the energy 

efficiency of residential and certain 

commercial water heaters 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 

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 


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impact of the commercial or industry 

standards on competition. 

The modifications to the test 

procedures addressed by this action 

incorporate testing methods contained 

in the following commercial standards: 

(1) ASTM D2156 09, ‘‘Standard Test 

Method for Smoke Density in Flue 

Gases from Burning Distillate Fuels’’; 

and (2) ASHRAE Standard 41.1–1986 

(RA 2006), ‘‘Standard Method for 

Temperature Measurement.’’ While this 

test procedure is not exclusively based 

on these standards, components of the 

test procedures are adopted directly 

from these standards without 

amendment. The Department has 

evaluated these standards and is unable 

to conclude whether they fully comply 

with the requirements of section 32(b) of 

the FEAA, (i.e., that they were 

developed in a manner that fully 

provides for public participation, 

comment, and review). DOE has 

consulted with the Attorney General 

and the Chairman of the FTC 

concerning the impact on competition 

of requiring manufacturers to use the 

test methods contained in these 

standards and has received no 

comments objecting to their use. 

M. Congressional Notification 

As required by 5 U.S.C. 801, DOE will 

report to Congress on the promulgation 

of this rule before its effective date. The 

report will state that it has been 

determined that the rule is not a ‘‘major 

rule’’ as defined by 5 U.S.C. 804(2). 

V. Approval of the Office of the 

Secretary 

The Secretary of Energy has approved 

publication of this final rule. 

List of Subjects 

10 CFR Part 429 

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 June 27, 

2014. 

Kathleen B. Hogan, 

Deputy Assistant Secretary for Energy 

Efficiency, Energy Efficiency and Renewable 

Energy. 

For the reasons stated in the 

preamble, DOE amends 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 

■ 1. The authority citation for part 429 

continues to read as follows: 

Authority: 42 U.S.C. 6291–6317. 

■ 2. Section 429.17 is amended by: 

■ a. Revising paragraphs (a) 

introductory text and (a)(1); 

■ b. Redesignating paragraphs— 

i. (a)(2)(i) introductory text as 

(a)(1)(ii)(A); 

ii. (a)(2)(i)(A) as (a)(1)(ii)(A)(1); 

iii. (a)(2)(1)(B) as (a)(1)(ii)(A)(2); 

iv. (a)(2)(ii) introductory text as 

(a)(1)(ii)(B); 

v. (a)(2)(ii)(A) as (a)(1)(ii)(B)(1); and 

vi. (a)(2)(ii)(B) as (a)(1)(ii)(B)(2); 

■ c. Adding paragraphs (a)(1)(ii)(C), and 

(D); 

■ d. Revising paragraph (a)(2); and 

■ e. Revising paragraph (b)(2). 

The revisions and additions read as 

follows: 

§ 429.17 Residential water heaters. 

(a) Determination of represented 

value. Manufacturers must determine 

the represented value, which includes 

the certified rating, for each basic model 

of residential water heater either by 

testing, in conjunction with the 

applicable sampling provisions, or by 

applying an alternative efficiency 

determination method (AEDM) 

approved for use by DOE. 

(1) Units to be tested. (i) If the 

represented value is determined through 

testing, the general requirements of 

§ 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— 

* * * * * 

(C) 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. 

(D) Any represented value of firsthour 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. 

(2) Alternative efficiency 

determination methods. In lieu of 

testing, represented values for a basic 

model must be determined through the 

application of an AEDM pursuant to the 

requirements of § 429.70. 

(b) * * * 

(2) Pursuant to § 429.12(b)(13), a 

certification report shall include the 

following public product-specific 

information: The uniform energy factor 

(UEF, rounded to the nearest 0.01), rated 

storage volume in gallons (gal), firsthour rating or maximum gallons per 

minute (GPM), and recovery efficiency 

(percent). 

■ 3. Section 429.44 is amended by: 

■ a. Redesignating paragraphs (a), (b), 

and (c) as (b), (c), and (d), respectively. 

■ b. Adding new paragraph (a); and 

■ c. Revising newly redesignated 

paragraph (b). 

The revisions and additions read as 

follows: 

§ 429.44 Commercial water heating 

equipment. 

(a) For residential-duty commercial 

water heaters, all represented values 

must be determined in accordance with 

§ 429.17. 

(b) Determination of Represented 

Value for All Types of Commercial 

Water Heaters Except Residential-Duty 

Commercial Water Heaters. 

Manufacturers must determine the 

represented value, which includes the 

certified rating, for each basic model of 

commercial water heating equipment 

except residential-duty commercial 

water heaters, either by testing, in 

conjunction with the applicable 

sampling provisions, or by applying an 

AEDM as set forth in § 429.70. 

* * * * * 

■ 4. Section 429.70 is amended by 

adding paragraph (g) to read as follows: 

§ 429.70 Alternative methods for 

determining energy efficiency and energy 

use 

* * * * * 

(g) Alternative determination of 

ratings for untested basic models of 

residential water heaters and 

residential-duty commercial water 

heaters. For models of water heaters that 

differ only in fuel type or power input, 

ratings for untested basic models may be 

established in accordance with the 

following procedures in lieu of testing. 

This method allows only for the use of 

ratings identical to those of a tested 

basic model as provided below; 

simulations or other modeling 

predictions for ratings of the uniform 


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40566 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

energy factor, volume, first-hour rating, 

or maximum gallons per minute (GPM) 

are not permitted. 

(1) Gas Water Heaters. For untested 

basic models of gas-fired water heaters 

that differ from tested basic models only 

in whether the basic models use natural 

gas or propane gas, the represented 

value of uniform energy factor, firsthour rating, and maximum gallons per 

minute for an untested basic model is 

the same as that for a tested basic 

model, as long as the input ratings of the 

tested and untested basic models are 

within ±10%, that is: 

(2) Electric Storage Water Heaters. 

Rate an untested basic model of an 

electric storage type water heater using 

the first-hour rating and the uniform 

energy factor obtained from a tested 

basic model as a basis for ratings of 

basic models with other input ratings, 

provided that certain conditions are 

met: 

(i) For an untested basic model, the 

represented value of the first-hour rating 

and the uniform energy factor is the 

same as that of a tested basic model, 

provided that each heating element of 

the untested basic model is rated at or 

above the input rating for the 

corresponding heating element of the 

tested basic model. 

(ii) For an untested basic model 

having any heating element with an 

input rating that is lower than that of 

the corresponding heating element in 

the tested basic model, the represented 

value of the first-hour rating and the 

uniform energy factor is the same as that 

of a tested basic model, provided that 

the first-hour rating for the untested 

basic model results in the same draw 

pattern specified in Table I of appendix 

E for the simulated-use test as was 

applied to the tested basic model. To 

establish whether this condition is met, 

determine the first-hour ratings for the 

tested and the untested basic models in 

accordance with the procedure 

described in section 5.3.3 of 10 CFR part 

430, subpart B, appendix E, then 

compare the appropriate draw pattern 

specified in Table I of appendix E for 

the first-hour rating of the tested basic 

model with that for the untested basic 

model. If this condition is not met, then 

the untested basic model must be tested 

and the appropriate sampling provisions 

applied to determine its uniform energy 

factor in accordance with appendix E 

and this part. 

■ 5. Section 429.134 is amended by 

removing and reserving paragraph (c) 

and adding paragraph (d) to read as 

follows: 

§ 429.134 Product-specific enforcement 

provisions. 

* * * * * 

(d) Residential Water Heaters and 

Residential-Duty Commercial Water 

Heaters—(1) Verification of first-hour 

rating and maximum GPM rating. The 

first-hour rating or maximum gallons 

per minute (GPM) rating of the basic 

model will be measured pursuant to the 

test requirements of 10 CFR part 430 for 

each unit tested. The mean of the 

measured values will be compared to 

the rated values of first-hour rating or 

maximum GPM rating as certified by the 

manufacturer. The certified rating will 

be considered valid only if the 

measurement is within five percent of 

the certified rating. 

(i) If the rated value of first-hour 

rating or maximum GPM rating is found 

to be within 5 percent of the mean of the 

measured values, then the rated value 

will be used as the basis for determining 

the applicable draw pattern pursuant to 

the test requirements of 10 CFR part 430 

for each unit tested. 

(ii) If the rated value of first-hour 

rating or maximum GPM rating is found 

to vary more than 5 percent from the 

measured values, then the mean of the 

measured values will serve as the basis 

for determining the applicable draw 

pattern pursuant to the test 

requirements of 10 CFR part 430 for 

each unit tested. 

(2) Verification of rated storage 

volume. The storage volume of the basic 

model will be measured pursuant to the 

test requirements of 10 CFR part 430 for 

each unit tested. The mean of the 

measured values will be compared to 

the rated storage volume as certified by 

the manufacturer. The rated value will 

be considered valid only if the 

measurement is within five percent of 

the certified rating. 

(i) If the rated storage volume is found 

to be within 5 percent of the mean of the 

measured value of storage volume, then 

that value will be used as the basis for 

calculation of the required uniform 

energy factor for the basic model. 

(ii) If the rated storage volume is 

found to vary more than 5 percent from 

the mean of the measured values, then 

the mean of the measured values will be 

used as the basis for calculation of the 

required uniform energy factor for the 

basic model. 

PART 430—ENERGY CONSERVATION 

PROGRAM FOR CONSUMER 

PRODUCTS 

■ 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. 

■ 7. Section 430.2 is amended by adding 

the definitions of ‘‘Electric heat pump 

water heater,’’ ‘‘Electric instantaneous 

water heater,’’ ‘‘Electric storage water 

heater,’’ ‘‘Gas-fired instantaneous water 

heater,’’ ‘‘Gas-fired storage water 

heater,’’ ‘‘Gas-fired heat pump water 

heater,’’ ‘‘Oil-fired instantaneous water 

heater,’’ and ‘‘Oil-fired storage water 

heater’’ in alphabetical order to read as 

follows: 

§ 430.2 Definitions. 

* * * * * 

Electric heat pump water heater 

means a water heater that uses 

electricity as the energy source, has a 

maximum current rating of 24 amperes 

(including the compressor and all 

auxiliary equipment such as fans, 

pumps, controls, and, if on the same 

circuit, any resistive elements) at an 

input voltage of no greater than 250 

volts, has a rated storage capacity of 120 

gallons (450 liters) or less, is designed 

to transfer thermal energy from one 

temperature level to a higher 

temperature level for the purpose of 

heating water, including all ancillary 

equipment such as fans, storage tanks, 

pumps, or controls necessary for the 

device to perform its function, and is 

designed to heat and store water at a 

thermostatically-controlled temperature 

less than or equal to 180 °F (82 °C). 

* * * * * 

Electric instantaneous water heater 

means a water heater that uses 

electricity as the energy source, has a 

nameplate input rating of 12 kW (40,956 

Btu/h) or less, contains no more than 

one gallon of water per 4,000 Btu per 

hour of input, and is designed to 

provide outlet water at a controlled 

temperature less than or equal to 180 °F 

(82 °C). The unit may use a fixed or 

variable burner input. 

* * * * * 


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Electric storage water heater means a 

water heater that uses electricity as the 

energy source, has a nameplate input 

rating of 12 kW (40,956 Btu/h) or less, 

has a rated storage capacity of 120 

gallons (450 liters) or less, contains 

more than one gallon of water per 4,000 

Btu per hour of input, and may be 

designed to heat and store water at a 

thermostatically-controlled temperature 

less than or equal to 180 °F (82 °C). 

* * * * * 

Gas-fired heat pump water heater 

means a water heater that uses gas as the 

main energy source, has a nameplate 

input rating of 75,000 Btu/h (79 MJ/h) 

or less, has a maximum current rating of 

24 amperes (including all auxiliary 

equipment such as fans, pumps, 

controls, and, if on the same circuit, any 

resistive elements) at an input voltage of 

no greater than 250 volts, has a rated 

storage volume not more than 120 

gallons (450 liters), and is designed to 

transfer thermal energy from one 

temperature level to a higher 

temperature level to deliver water at a 

thermostatically controlled temperature 

less than or equal to 180 °F (82 °C). 

Gas-fired instantaneous water heater 

means a water heater that uses gas as the 

main energy source, has a nameplate 

input rating less than 200,000 Btu/h 

(210 MJ/h), contains no more than one 

gallon of water per 4,000 Btu per hour 

of input, and is designed to provide 

outlet water at a controlled temperature 

less than or equal to 180 °F (82 °C). The 

unit may use a fixed or variable burner 

input. 

Gas-fired storage water heater means 

a water heater that uses gas as the main 

energy source, has a nameplate input 

rating of 75,000 Btu/h (79 MJ/h) or less, 

has a rated storage capacity of 120 

gallons (450 liters) or less, contains 

more than one gallon of water per 4,000 

Btu per hour of input, and is designed 

to heat and store water at a 

thermostatically-controlled temperature 

less than or equal to 180 °F (82 °C). 

* * * * * 

Oil-fired instantaneous water heater 

means a water heater that uses oil as the 

main energy source, has a nameplate 

input rating of 210,000 Btu/h (220 MJ/ 

h) or less, contains no more than one 

gallon of water per 4,000 Btu per hour 

of input, and is designed to provide 

outlet water at a controlled temperature 

less than or equal to 180 °F (82 °C). The 

unit may use a fixed or variable burner 

input. 

Oil-fired storage water heater means a 

water heater that uses oil as the main 

energy source, has a nameplate input 

rating of 105,000 Btu/h (110 MJ/h) or 

less, has a rated storage capacity of 120 

gallons (450 liters) or less, contains 

more than one gallon of water per 4,000 

Btu per hour of input, and is designed 

to heat and store water at a 

thermostatically-controlled temperature 

less than or equal to 180 °F (82 °C). 

* * * * * 

■ 8. Section 430.3 is amended by: 

■ a. Redesignating paragraphs (h) 

through (t) as (i) through (u), 

respectively; and 

■ b. Adding a new paragraph (h). 

The addition reads as follows: 

§ 430.3 Materials incorporated by 

reference. 

* * * * * 

(h) ASTM. American Society for 

Testing and Materials International, 100 

Barr Harbor Drive, P.O. Box C700, West 

Conshohocken, PA 19428–2959 

(www.astm.org). 

(1) ASTM D 2156–09 (‘‘ASTM 

D2156’’), Standard Test Method for 

Smoke Density in Flue Gases from 

Burning Distillate Fuels, approved 

December 1, 2009, IBR approved for 

appendix E to subpart B. 

(2) [Reserved]. 

* * * * * 

■ 9. Section 430.23 is amended by 

revising paragraph (e) to read as follows: 

§ 430.23 Test procedures for the 

measurement of energy and water 

consumption. 

* * * * * 

(e) Water Heaters. (1) The estimated 

annual operating cost for water heaters 

shall be— 

(i) 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 then being 

rounded off to the nearest dollar per 

year. 

(ii) 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 then 

being rounded off to the nearest dollar 

per year. 

(2) For an individual test, the tested 

uniform energy factor for a water heater 

shall be— 

(i) For a gas or oil water heater, as 

determined by section 6.1.7 or 6.2.4 of 

appendix E of this subpart rounded to 

the nearest 0.01. 

(ii) For an electric water heater, as 

determined by section 6.1.7 or 6.2.4 of 

appendix E of this subpart rounded to 

the nearest 0.01. 

* * * * * 

■ 10. Appendix E to Subpart B of Part 

430 is revised to read as follows: 

Appendix E to Subpart B of Part 430– 

Uniform Test Method for Measuring the 

Energy Consumption of Water Heaters 

Note: After December 31, 2015, any 

representations made with respect to the 

energy use or efficiency of residential water 

heaters and commercial water heaters 

covered by this test method must be made in 

accordance with the results of testing 

pursuant to this appendix. (Because the 

statute permits use of a conversion factor 

until the later of December 31, 2015 or one 

year after publication of a conversion factor 

final rule, DOE may amend the mandatory 

compliance date for use of this amended test 

procedure, as necessary.) 

Manufacturers conducting tests of 

residential water heaters and commercial 

water heaters covered by this test method 

after July 13, 2015, and prior to December 31, 

2015, must conduct such test in accordance 

with either this appendix or the previous test 

method. For residential water heaters, the 

previous test method is appendix E as it 

appeared at 10 CFR part 430, subpart B, 

appendix E, in the 10 CFR parts 200 to 499 

edition revised as of January 1, 2014. For 

commercial water heaters, the previous test 

method is 10 CFR 431.106 in the 10 CFR 

parts 200 to 499 edition revised as of January 

1, 2014. Any representations made with 

respect to the energy use or efficiency of such 

water heaters must be in accordance with 

whichever version is selected. 

1. Definitions. 

1.1. Cut-in means the time when or water 

temperature at which a water heater control 

or thermostat acts to increase the energy or 

fuel input to the heating elements, 

compressor, or burner. 

1.2. Cut-out means the time when or water 

temperature at which a water heater control 

or thermostat acts to reduce to a minimum 

the energy or fuel input to the heating 

elements, compressor, or burner. 

1.3. Design Power Rating means the 

nominal power rating that a water heater 

manufacturer assigns to a particular design of 

water heater, expressed in kilowatts or Btu 

(kJ) per hour as appropriate. 

1.4. Draw Cluster means a collection of 

water draws initiated during the simulateduse test during which no successive draws 

are separated by more than 2 hours. 

1.5. First-Hour Rating means an estimate of 

the maximum volume of ‘‘hot’’ water that a 

storage-type water heater can supply within 


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an hour that begins with the water heater 

fully heated (i.e., with all thermostats 

satisfied). It is a function of both the storage 

volume and the recovery rate. 

1.6. Flow-activated describes an 

operational scheme in which a water heater 

initiates and terminates heating based on 

sensing flow. 

1.7. Heat Trap means a device that can be 

integrally connected or independently 

attached to the hot and/or cold water pipe 

connections of a water heater such that the 

device will develop a thermal or mechanical 

seal to minimize the recirculation of water 

due to thermal convection between the water 

heater tank and its connecting pipes. 

1.8. Maximum GPM (L/min) Rating means 

the maximum gallons per minute (liters per 

minute) of hot water that can be supplied by 

an instantaneous water heater while 

maintaining a nominal temperature rise of 

67 °F (37.3 °C) during steady-state operation, 

as determined by testing in accordance with 

section 5.3.2 of this appendix. 

1.9. Rated Storage Volume means the water 

storage capacity of a water heater, in gallons 

(liters), as certified by the manufacturer 

pursuant to 10 CFR part 429. 

1.10. Recovery Efficiency means the ratio of 

energy delivered to the water to the energy 

content of the fuel consumed by the water 

heater. 

1.11. Recovery Period means the time when 

the main burner of a storage water heater is 

raising the temperature of the stored water. 

1.12. Standby means the time, in hours, 

during which water is not being withdrawn 

from the water heater. There are two standby 

time intervals used within this test 

procedure: tstby,1 represents the elapsed time 

between the time at which the maximum 

mean tank temperature is observed after the 

first draw cluster and the minute prior to the 

start of the first draw following the end of the 

first draw cluster of the 24-hour simulateduse test; tstby,2 represents the total time 

during the 24-hour simulated-use test when 

water is not being withdrawn from the water 

heater. 

1.13. Symbol Usage. The following identity 

relationships are provided to help clarify the 

symbology used throughout this procedure: 

Cp—specific heat of water 

Eannual—annual energy consumption of a 

water heater 

Eannual,e—annual electrical energy 

consumption of a water heater 

Eannual,f—annual fossil-fuel energy 

consumption of a water heater 

Fhr—first-hour rating of a storage-type water 

heater 

Fmax—maximum GPM (L/min) rating of an 

instantaneous water heater rated at a 

temperature rise of 67 °F (37.3 °C) 

i—a subscript to indicate the draw number 

during a test 

Mi—mass of water removed during the ith 

draw of the 24-hour simulated-use test 

M*i—for storage-type water heaters, mass of 

water removed during the ith draw 

during the first-hour rating test 

M10m—for instantaneous water heaters, mass 

of water removed continuously during a 

10-minute interval in the maximum GPM 

(L/min) rating test 

n—for storage-type water heaters, total 

number of draws during the first-hour 

rating test 

N—total number of draws during the 24-hour 

simulated-use test 

Q—total fossil fuel and/or electric energy 

consumed during the entire 24-hour 

simulated-use test 

Qd—daily water heating energy consumption 

adjusted for net change in internal 

energy 

Qda—Qd with adjustment for variation of tank 

to ambient air temperature difference 

from nominal value 

Qdm—overall adjusted daily water heating 

energy consumption including Qda and 

QHWD

Qe—total electrical energy used during the 

24-hour simulated-use test 

Qf—total fossil fuel energy used by the water 

heater during the 24-hour simulated-use 

test 

Qhr—hourly standby losses 

QHW—daily energy consumption to heat 

water at the measured average 

temperature rise across the water heater 

QHW,67 °F—daily energy consumption to heat 

quantity of water removed during test 

over a temperature rise of 67 °F (37.3 °C) 

QHWD—adjustment to daily energy 

consumption, QHW, due to variation of 

the temperature rise across the water 

heater not equal to the nominal value of 

67 °F 

Qr—energy consumption of water heater 

from the beginning of the test to the end 

of the first recovery period following the 

first draw, which may extend beyond 

subsequent draws 

Qstby—total energy consumed by the water 

heater during the standby time interval 

tstby,1

Qsu,0—total fossil fuel and/or electric energy 

consumed from the beginning of the test 

to the end of the cutout following the 

first draw cluster 

Qsu,f—total fossil fuel and/or electric energy 

consumed from the beginning of the test 

to the initiation of the first draw 

following the first draw cluster 

T0—mean tank temperature at the beginning 

of the 24-hour simulated-use test 

T24—mean tank temperature at the end of the 

24-hour simulated-use test 

Ta,stby—average ambient air temperature 

during standby periods of the 24-hour 

simulated-use test 

Tdel—for flow-activated water heaters, 

average outlet water temperature during 

a 10-minute continuous draw interval in 

the maximum GPM (L/min) rating test 

Tdel,i—average outlet water temperature 

during the ith draw of the 24-hour 

simulated-use test 

Tin—for flow-activated water heaters, average 

inlet water temperature during a 10- 

minute continuous draw interval in the 

maximum GPM (L/min) rating test 

Tin,i—average inlet water temperature during 

the ith draw of the 24-hour simulateduse test 

Tmax,1—maximum measured mean tank 

temperature after cut-out following the 

first draw of the 24-hour simulated-use 

test 

Tsu,0—maximum measured mean tank 

temperature at the beginning of the 

standby period which occurs after cutout following the final draw of the first 

draw cluster 

Tsu,f—measured mean tank temperature at the 

end of the standby period which occurs 

at the minute prior to commencement of 

the first draw that follows the end of the 

first draw cluster 

T*del,i—for storage-type water heaters, 

average outlet water temperature during 

the ith draw (i = 1 to n) of the first-hour 

rating test 

T*max,i—for storage-type water heaters, 

maximum outlet water temperature 

observed during the ith draw (i = 1 to n) 

of the first-hour rating test 

T*min,i—for storage-type water heaters, 

minimum outlet water temperature to 

terminate the ith draw (i = 1 to n) of the 

first-hour rating test 

UA—standby loss coefficient of a storagetype water heater 

UEF—uniform energy factor of a water heater 

Vi—volume of water removed during the ith 

draw (i = 1 to N) of the 24-hour 

simulated-use test 

V*i—volume of water removed during the ith 

draw (i = 1 to n) of the first-hour rating 

test 

V10m—for flow-activated water heaters, 

volume of water removed continuously 

during a 10-minute interval in the 

maximum GPM (L/min) rating test 

Vst—measured storage volume of the storage 

tank 

Wf—weight of storage tank when completely 

filled with water 

Wt—tare weight of storage tank when 

completely empty of water 

hr—recovery efficiency 

r—density of water 

tstby,1—elapsed time between the time the 

maximum mean tank temperature is 

observed after the first draw cluster and 

the minute prior to the start of the first 

draw following the first draw cluster 

tstby,2—overall time of standby periods when 

no water is withdrawn during the 24- 

hour simulated-use test 

1.14. Temperature controller means a 

device that is available to the user to adjust 

the temperature of the water inside a storagetype water heater or the outlet water 

temperature. 

1.15. Uniform Energy Factor means the 

measure of water heater overall efficiency. 

2. Test Conditions. 

2.1 Installation Requirements. Tests shall 

be performed with the water heater and 

instrumentation installed in accordance with 

section 4 of this appendix. 

2.2 Ambient Air Temperature. The 

ambient air temperature shall be maintained 

between 65.0 °F and 70.0 °F (18.3 °C and 21.1 

°C) on a continuous basis. For heat pump 

water heaters, the dry bulb temperature shall 

be maintained at 67.5 °F ± 1 °F (19.7 °C ± 0.6 

°C) and the relative humidity shall be 

maintained at 50% ± 2% throughout the test. 

2.3 Supply Water Temperature. The 

temperature of the water being supplied to 

the water heater shall be maintained at 58 °F 

± 2 °F (14.4 °C ± 1.1 °C) throughout the test. 

2.4 Outlet Water Temperature. The 

temperature controllers of a storage-type 


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water heater shall be set so that water is 

delivered at a temperature of 125 °F ± 5 °F 

(51.7 °C ± 2.8 °C). 

2.5 Set Point Temperature. The 

temperature controller of instantaneous water 

heaters shall be set to deliver water at a 

temperature of 125 °F ± 5 °F (51.7 °C ± 2.8 

°C). 

2.6 Supply Water Pressure. During the 

test when water is not being withdrawn, the 

supply pressure shall be maintained between 

40 psig (275 kPa) and the maximum 

allowable pressure specified by the water 

heater manufacturer. 

2.7 Electrical and/or Fossil Fuel Supply. 

2.7.1 Electrical. Maintain the electrical 

supply voltage to within ±1% of the center 

of the voltage range specified by the water 

heater and/or heat pump manufacturer. 

2.7.2 Natural Gas. Maintain the supply 

pressure in accordance with the 

manufacturer’s specifications. If the supply 

pressure is not specified, maintain a supply 

pressure of 7–10 inches of water column 

(1.7–2.5 kPa). If the water heater is equipped 

with a gas appliance pressure regulator, the 

regulator outlet pressure shall be within ± 

10% of the manufacturer’s specified 

manifold pressure. For all tests, use natural 

gas having a heating value of approximately 

1,025 Btu per standard cubic foot (38,190 kJ 

per standard cubic meter). 

2.7.3 Propane Gas. Maintain the supply 

pressure in accordance with the 

manufacturer’s specifications. If the supply 

pressure is not specified, maintain a supply 

pressure of 11–13 inches of water column 

(2.7–3.2 kPa). If the water heater is equipped 

with a gas appliance pressure regulator, the 

regulator outlet pressure shall be within ± 

10% of the manufacturer’s specified 

manifold pressure. For all tests, use propane 

gas with a heating value of approximately 

2,500 Btu per standard cubic foot (93,147 kJ 

per standard cubic meter). 

2.7.4 Fuel Oil Supply. Maintain an 

uninterrupted supply of fuel oil. Use fuel oil 

having a heating value of approximately 

138,700 Btu per gallon (38,660 kJ per liter). 

3. Instrumentation 

3.1 Pressure Measurements. Pressuremeasuring instruments shall have an error no 

greater than the following values: 

Item measured Instrument accuracy Instrument precision 

Gas pressure ..................................................... ±0.1 inch of water column (±0.025 kPa) .......... ±0.05 inch of water column (±0.012 kPa). 

Atmospheric pressure ........................................ ±0.1 inch of mercury column (±0.34 kPa) ....... ±0.05 inch of mercury column (±0.17 kPa). 

Water pressure .................................................. ±1.0 pounds per square inch (±6.9 kPa) ......... ±0.50 pounds per square inch (±3.45 kPa). 

3.2 Temperature Measurement 

3.2.1 Measurement. Temperature 

measurements shall be made in accordance 

with the Standard Method for Temperature 

Measurement, ASHRAE 41.1–1986 

(incorporated by reference, see § 430.3). 

3.2.2 Accuracy and Precision. The 

accuracy and precision of the instruments, 

including their associated readout devices, 

shall be within the following limits: 

Item measured Instrument accuracy Instrument precision 

Air dry bulb temperature .................................... ±0.2°F (±0.1°C) ................................................ ±0.1°F (±0.06°C). 

Air wet bulb temperature ................................... ±0.2°F (±0.1°C) ................................................ ±0.1°F (±0.06°C). 

Inlet and outlet water temperatures ................... ±0.2°F (±0.1°C) ................................................ ±0.1°F (±0.06°C). 

Storage tank temperatures ................................ ±0.5°F (±0.3°C) ................................................ ±0.25°F (±0.14°C). 

3.2.3 Scale Division. In no case shall the 

smallest scale division of the instrument or 

instrument system exceed 2 times the 

specified precision. 

3.2.4 Temperature Difference 

Temperature difference between the entering 

and leaving water may be measured with any 

of the following: 

a. A thermopile 

b. Calibrated resistance thermometers 

c. Precision thermometers 

d. Calibrated thermistors 

e. Calibrated thermocouples 

f. Quartz thermometers 

3.2.5 Thermopile Construction. If a 

thermopile is used, it shall be made from 

calibrated thermocouple wire taken from a 

single spool. Extension wires to the recording 

device shall also be made from that same 

spool. 

3.2.6 Time Constant. The time constant of 

the instruments used to measure the inlet 

and outlet water temperatures shall be no 

greater than 2 seconds. 

3.3 Liquid Flow Rate Measurement. The 

accuracy of the liquid flow rate 

measurement, using the calibration if 

furnished, shall be equal to or less than ±1% 

of the measured value in mass units per unit 

time. 

3.4 Electrical Energy. The electrical 

energy used shall be measured with an 

instrument and associated readout device 

that is accurate within ±0.5% of the reading. 

3.5 Fossil Fuels. The quantity of fuel used 

by the water heater shall be measured with 

an instrument and associated readout device 

that is accurate within ±1% of the reading. 

3.6 Mass Measurements. For mass 

measurements greater than or equal to 10 

pounds (4.5 kg), a scale that is accurate 

within ±0.5% of the reading shall be used to 

make the measurement. For mass 

measurements less than 10 pounds (4.5 kg), 

the scale shall provide a measurement that is 

accurate within ±0.1 pound (0.045 kg). 

3.7 Heating Value. The higher heating 

value of the natural gas, propane, or fuel oil 

shall be measured with an instrument and 

associated readout device that is accurate 

within ±1% of the reading. The heating 

values of natural gas and propane must be 

corrected from those reported at standard 

temperature and pressure conditions to 

provide the heating value at the temperature 

and pressure measured at the fuel meter. 

3.8 Time. The elapsed time 

measurements shall be measured with an 

instrument that is accurate within ±0.5 

seconds per hour. 

3.9 Volume. Volume measurements shall 

be measured with an accuracy of ±2% of the 

total volume. 

3.10 Relative Humidity. If a relative 

humidity (RH) transducer is used to measure 

the relative humidity of the surrounding air 

while testing heat pump water heaters, the 

relative humidity shall be measured with an 

accuracy of ±1.5% RH. 

4. Installation 

4.1 Water Heater Mounting. A water 

heater designed to be freestanding shall be 

placed on a 3⁄4 inch (2 cm) thick plywood 

platform supported by three 2 x 4 inch (5 cm 

x 10 cm) runners. If the water heater is not 

approved for installation on combustible 

flooring, suitable non-combustible material 

shall be placed between the water heater and 

the platform. Counter-top water heaters shall 

be placed against a simulated wall section. 

Wall-mounted water heaters shall be 

supported on a simulated wall in accordance 

with the manufacturer-published installation 

instructions. When a simulated wall is used, 

the construction shall be 2 x 4 inch (5 cm x 

10 cm) studs, faced with 3⁄4 inch (2 cm) 

plywood. For heat pump water heaters not 

delivered as a single package, the units shall 

be connected in accordance with the 

manufacturer-published installation 

instructions and the overall system shall be 

placed on the above-described plywood 

platform. If installation instructions are not 

provided by the heat pump manufacturer, 

uninsulated 8 foot (2.4 m) long connecting 

hoses having an inside diameter of 5/8 inch 

(1.6 cm) shall be used to connect the storage 

tank and the heat pump water heater. The 

testing of the water heater shall occur in an 

area that is protected from drafts of more 

than 50 ft/min (0.25 m/s) from room 

ventilation registers, windows, or other 

external sources of air movement. 


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4.2 Water Supply. Connect the water 

heater to a water supply capable of delivering 

water at conditions as specified in sections 

2.3 and 2.6 of this appendix. 

4.3 Water Inlet and Outlet Configuration. 

For freestanding water heaters that are taller 

than 36 inches (91.4 cm), inlet and outlet 

piping connections shall be configured in a 

manner consistent with Figures 1 and 2 of 

section 6.4.6 of this appendix. Inlet and 

outlet piping connections for wall-mounted 

water heaters shall be consistent with Figure 

3 of section 6.4.6 of this appendix. For 

freestanding water heaters that are 36 inches 

or less in height and not supplied as part of 

a counter-top enclosure (commonly referred 

to as an under-the-counter model), inlet and 

outlet piping shall be installed in a manner 

consistent with Figures 4, 5, or 6 of section 

6.4.6 of this appendix. For water heaters that 

are supplied with a counter-top enclosure, 

inlet and outlet piping shall be made in a 

manner consistent with Figures 7a and 7b of 

section 6.4.6 of this appendix, respectively. 

The vertical piping noted in Figures 7a and 

7b shall be located (whether inside the 

enclosure or along the outside in a recessed 

channel) in accordance with the 

manufacturer-published installation 

instructions. 

All dimensions noted in Figures 1 through 

7 of section 6.4.6 of this appendix must be 

achieved. All piping between the water 

heater and inlet and outlet temperature 

sensors, noted as TIN and TOUT in the figures, 

shall be Type ‘‘L’’ hard copper having the 

same diameter as the connections on the 

water heater. Unions may be used to facilitate 

installation and removal of the piping 

arrangements. Install a pressure gauge and 

diaphragm expansion tank in the supply 

water piping at a location upstream of the 

inlet temperature sensor. Install an 

appropriately rated pressure and temperature 

relief valve on all water heaters at the port 

specified by the manufacturer. Discharge 

piping for the relief valve must be nonmetallic. If heat traps, piping insulation, or 

pressure relief valve insulation are supplied 

with the water heater, they must be installed 

for testing. Except when using a simulated 

wall, provide sufficient clearance such that 

none of the piping contacts other surfaces in 

the test room. 

4.4 Fuel and/or Electrical Power and 

Energy Consumption. Install one or more 

instruments that measure, as appropriate, the 

quantity and rate of electrical energy and/or 

fossil fuel consumption in accordance with 

section 3 of this appendix. 

4.5 Internal Storage Tank Temperature 

Measurements. For water heaters with rated 

storage volumes greater than or equal to 20 

gallons, install six temperature measurement 

sensors inside the water heater tank with a 

vertical distance of at least 4 inches (100 mm) 

between successive sensors. For water 

heaters with rated storage volumes between 

2 and 20 gallons, install three temperature 

measurement sensors inside the water heater 

tank. Position a temperature sensor at the 

vertical midpoint of each of the six equal 

volume nodes within a tank larger than 20 

gallons or the three equal volume nodes 

within a tank between 2 and 20 gallons. 

Nodes designate the equal volumes used to 

evenly partition the total volume of the tank. 

As much as is possible, the temperature 

sensor should be positioned away from any 

heating elements, anodic protective devices, 

tank walls, and flue pipe walls. If the tank 

cannot accommodate six temperature sensors 

and meet the installation requirements 

specified above, install the maximum 

number of sensors that comply with the 

installation requirements. Install the 

temperature sensors through: (1) The anodic 

device opening; (2) the relief valve opening; 

or (3) the hot water outlet. If installed 

through the relief valve opening or the hot 

water outlet, a tee fitting or outlet piping, as 

applicable, must be installed as close as 

possible to its original location. If the relief 

valve temperature sensor is relocated, and it 

no longer extends into the top of the tank, 

install a substitute relief valve that has a 

sensing element that can reach into the tank. 

If the hot water outlet includes a heat trap, 

install the heat trap on top of the tee fitting. 

Cover any added fittings with thermal 

insulation having an R value between 4 and 

8 h·ft2·°F/Btu (0.7 and 1.4 m2·°C/W). 

4.6 Ambient Air Temperature 

Measurement. Install an ambient air 

temperature sensor at the vertical mid-point 

of the water heater and approximately 2 feet 

(610 mm) from the surface of the water 

heater. Shield the sensor against radiation. 

4.7 Inlet and Outlet Water Temperature 

Measurements. Install temperature sensors in 

the cold-water inlet pipe and hot-water outlet 

pipe as shown in Figures 1, 2, 3, 4, 5, 6, 7a, 

and 7b of section 6.4.6 of this appendix, as 

applicable. 

4.8 Flow Control. Install a valve or valves 

to provide flow as specified in sections 5.3 

and 5.4 of this appendix. 

4.9 Flue Requirements. 

4.9.1 Gas-Fired Water Heaters. Establish a 

natural draft in the following manner. For 

gas-fired water heaters with a vertically 

discharging draft hood outlet, connect to the 

draft hood outlet a 5-foot (1.5-meter) vertical 

vent pipe extension with a diameter equal to 

the largest flue collar size of the draft hood. 

For gas-fired water heaters with a 

horizontally discharging draft hood outlet, 

connect to the draft hood outlet a 90-degree 

elbow with a diameter equal to the largest 

flue collar size of the draft hood, connect a 

5-foot (1.5-meter) length of vent pipe to that 

elbow, and orient the vent pipe to discharge 

vertically upward. Install direct-vent gasfired water heaters with venting equipment 

specified in the manufacturer’s instructions 

using the minimum vertical and horizontal 

lengths of vent pipe recommended by the 

manufacturer. 

4.9.2 Oil-Fired Water Heaters. Establish a 

draft at the flue collar at the value specified 

in the manufacturer’s instructions. Establish 

the draft by using a sufficient length of vent 

pipe connected to the water heater flue 

outlet, and directed vertically upward. For an 

oil-fired water heater with a horizontally 

discharging draft hood outlet, connect to the 

draft hood outlet a 90-degree elbow with a 

diameter equal to the largest flue collar size 

of the draft hood, connect to the elbow fitting 

a length of vent pipe sufficient to establish 

the draft, and orient the vent pipe to 

discharge vertically upward. Direct-vent oilfired water heaters should be installed with 

venting equipment as specified in the 

manufacturer’s instructions, using the 

minimum vertical and horizontal lengths of 

vent pipe recommended by the manufacturer. 

5. Test Procedures 

5.1 Operational Mode Selection. For 

water heaters that allow for multiple userselected operational modes, all procedures 

specified in this appendix shall be carried 

out with the water heater in the same 

operational mode (i.e., only one mode). This 

operational mode shall be the default mode 

(or similarly-named, suggested mode for 

normal operation) as defined by the 

manufacturer in its product literature for 

giving selection guidance to the consumer. 

For heat pump water heaters, if a default 

mode is not defined in the product literature, 

each test shall be conducted under an 

operational mode in which both the heat 

pump and any electric resistance backup 

heating element(s) are activated by the unit’s 

control scheme, and which can achieve the 

internal storage tank temperature specified in 

this test procedure; if multiple operational 

modes meet these criteria, the water heater 

shall be tested under the most energyintensive mode. If no default mode is 

specified and the unit does not offer an 

operational mode that utilizes both the heat 

pump and the electric resistance backup 

heating element(s), the first-hour rating test 

and the simulated-use test shall be tested in 

heat-pump-only mode. For other types of 

water heaters where a default mode is not 

specified, test the unit in all modes and rate 

the unit using the results of the most energyintensive mode. 

5.2 Water Heater Preparation. 

5.2.1 Determination of Storage Tank 

Volume. For water heaters with a rated 

storage volume greater than or equal to 2 

gallons, determine the storage capacity, Vst, of 

the water heater under test, in gallons (liters), 

by subtracting the tare weight—measured 

while the tank is empty—from the gross 

weight of the storage tank when completely 

filled with water (with all air eliminated and 

line pressure applied as described in section 

2.5 of this appendix) and dividing the 

resulting net weight by the density of water 

at the measured temperature. 

5.2.2 Setting the Outlet Discharge 

Temperature. 

5.2.2.1 Flow-Activated Water Heaters, 

including certain instantaneous water 

heaters and certain storage-type water 

heaters. Initiate normal operation of the 

water heater at the full input rating for 

electric water heaters and at the maximum 

firing rate specified by the manufacturer for 

gas or oil water heaters. Monitor the 

discharge water temperature and set to a 

value of 125 °F ± 5 °F (51.7 °C ± 2.8 °C) in 

accordance with the manufacturer’s 

instructions. If the water heater is not capable 

of providing this discharge temperature when 

the flow rate is 1.7 gallons ± 0.25 gallons per 

minute (6.4 liters ± 0.95 liters per minute), 

then adjust the flow rate as necessary to 

achieve the specified discharge water 

temperature. Once the proper temperature 

control setting is achieved, the setting must 

remain fixed for the duration of the 


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maximum GPM test and the simulated-use 

test. 

5.2.2.2 Storage-Type Water Heaters that 

Are Not Flow-Activated. 

5.2.2.2.1 Tanks with a Single 

Temperature Controller. 

5.2.2.2.1.1 Water Heaters with Rated 

Volumes Less than 20 Gallons. Starting with 

a tank at the supply water temperature, 

initiate normal operation of the water heater. 

After cut-out, initiate a draw from the water 

heater at a flow rate of 1.0 gallon ± 0.25 

gallons per minute (3.8 liters ± 0.95 liters per 

minute) for 2 minutes. Starting 15 seconds 

after commencement of draw, record the 

outlet temperature at 15-second intervals 

until the end of the 2-minute period. 

Determine whether the maximum outlet 

temperature is within the range of 125 °F ± 

5 °F (51.7 °C ± 2.8 °C). If not, turn off the 

water heater, adjust the temperature 

controller, and then drain and refill the tank 

with supply water. Then, once again, initiate 

normal operation of the water heater, and 

repeat the 2-minute outlet temperature test 

following cut-out. Repeat this sequence until 

the maximum outlet temperature during the 

2-minute test is within 125 °F ± 5 °F (51.7 °C 

± 2.8 °C). Once the proper temperature 

control setting is achieved, the setting must 

remain fixed for the duration of the first-hour 

rating test and the simulated-use test such 

that a second identical simulated-use test run 

immediately following the one specified in 

section 5.4 would result in average delivered 

water temperatures that are within the 

bounds specified in section 2.4 of this 

appendix. 

5.2.2.2.1.2 Water Heaters with Rated 

Volumes Greater than or Equal to 20 Gallons. 

Starting with a tank at the supply water 

temperature, initiate normal operation of the 

water heater. After cut-out, initiate a draw 

from the water heater at a flow rate of 1.7 

gallons ± 0.25 gallons per minute (6.4 liters 

± 0.95 liters per minute) for 5 minutes. 

Starting 15 seconds after commencement of 

draw, record the outlet temperature at 15- 

second intervals until the end of the 5- 

minute period. Determine whether the 

maximum outlet temperature is within the 

range of 125 °F ± 5 °F (51.7 °C ± 2.8 °C). If 

not, turn off the water heater, adjust the 

temperature controller, and then drain and 

refill the tank with supply water. Then, once 

again, initiate normal operation of the water 

heater, and repeat the 5-minute outlet 

temperature test following cut-out. Repeat 

this sequence until the maximum outlet 

temperature during the 5-minute test is 

within of 125 °F ± 5 °F (51.7 °C ± 2.8 °C). 

Once the proper temperature control setting 

is achieved, the setting must remain fixed for 

the duration of the first-hour rating test and 

the simulated-use test such that a second 

identical simulated-use test run immediately 

following the one specified in section 5.4 

would result in average delivered water 

temperatures that are within the bounds 

specified in section 2.4 of this appendix. 

5.2.2.2.2 Tanks with Two or More 

Temperature Controllers. Verify the 

temperature controller set-point while 

removing water in accordance with the 

procedure set forth for the first-hour rating 

test in section 5.3.3 of this appendix. The 

following criteria must be met to ensure that 

all temperature controllers are set to deliver 

water at 125 °F ± 5 °F (51.7 °C ± 2.8 °C): 

(a) At least 50 percent of the water drawn 

during the first draw of the first-hour rating 

test procedure shall be delivered at a 

temperature of 125 °F ± 5 °F (51.7 °C ± 2.8 

°C). 

(b) No water is delivered above 130 °F 

(54.4 °C) during first-hour rating test. 

(c) The delivery temperature measured 15 

seconds after commencement of each draw 

begun prior to an elapsed time of 60 minutes 

from the start of the test shall be at 125 °F 

± 5 °F (51.7 °C ± 2.8 °C). 

If these conditions are not met, turn off the 

water heater, adjust the temperature 

controllers, and then drain and refill the tank 

with supply water. Repeat the procedure 

described at the start of section 5.2.2.2.2 until 

the criteria for setting the temperature 

controllers is met. 

If the conditions stated above are met, the 

data obtained during the process of verifying 

the temperature control set-points may be 

used in determining the first-hour rating 

provided that all other conditions and 

methods required in sections 2 and 5.2.4 in 

preparing the water heater were followed. 

5.2.3 Power Input Determination. For all 

water heaters except electric types, initiate 

normal operation (as described in section 5.1) 

and determine the power input, P, to the 

main burners (including pilot light power, if 

any) after 15 minutes of operation. If the 

water heater is equipped with a gas appliance 

pressure regulator, the regulator outlet 

pressure shall be set within ±10% of that 

recommended by the manufacturer. For oilfired water heaters, the fuel pump pressure 

shall be within ±10% of the manufacturer’s 

specified pump pressure. Adjust all burners 

to achieve an hourly Btu (kJ) rating that is 

within ±2% of the value specified by the 

manufacturer. For an oil-fired water heater, 

adjust the burner to give a CO2 reading 

recommended by the manufacturer and an 

hourly Btu (kJ) rating that is within ±2% of 

that specified by the manufacturer. Smoke in 

the flue may not exceed No. 1 smoke as 

measured by the procedure in ASTM D2156 

(incorporated by reference, see § 430.3). 

5.2.4 Soak-In Period for Water Heaters 

with Rated Storage Volumes Greater than or 

Equal to 2 Gallons. For storage-type water 

heaters and instantaneous water heaters 

having greater than 2 gallons (7.6 liters) of 

storage (including heat pump water heaters 

having greater than 2 gallons of storage), the 

water heater must sit filled with water and 

without any draws taking place for at least 

12 hours after initially being energized so as 

to achieve the nominal temperature set-point 

within the tank and with the unit connected 

to a power source. 

5.3 Delivery Capacity Tests. 

5.3.1 General. For flow-activated water 

heaters, conduct the maximum GPM test, as 

described in section 5.3.2, Maximum GPM 

Rating Test for Flow-Activated Water 

Heaters, of this appendix. For all other water 

heaters, conduct the first-hour rating test as 

described in section 5.3.3 of this appendix. 

5.3.2 Maximum GPM Rating Test for 

Flow-Activated Water Heaters. Establish 

normal water heater operation at the full 

input rate for electric water heaters and at the 

maximum firing rate for gas or oil water 

heaters with the discharge water temperature 

set in accordance with section 5.2.2.1 of this 

appendix. 

For this 10-minute test, either collect the 

withdrawn water for later measurement of 

the total mass removed or use a water meter 

to directly measure the water volume 

removed. Initiate water flow through the 

water heater and record the inlet and outlet 

water temperatures beginning 15 seconds 

after the start of the test and at subsequent 

5-second intervals throughout the duration of 

the test. At the end of 10 minutes, turn off 

the water. Determine and record the mass of 

water collected, M10m, in pounds (kilograms), 

or the volume of water, V10m, in gallons 

(liters). 

5.3.3 First-Hour Rating Test. 

5.3.3.1 General. During hot water draws 

for water heaters with rated storage volumes 

greater than or equal to 20 gallons, remove 

water at a rate of 3.0 ± 0.25 gallons per 

minute (11.4 ± 0.95 liters per minute). During 

hot water draws for storage-type water 

heaters with rated storage volumes below 20 

gallons, remove water at a rate of 1.0 ± 0.25 

gallon per minute (3.8 ± 0.95 liters per 

minute). Collect the water in a container that 

is large enough to hold the volume removed 

during an individual draw and is suitable for 

weighing at the termination of each draw to 

determine the total volume of water 

withdrawn. As an alternative to collecting 

the water, a water meter may be used to 

directly measure the water volume(s) 

withdrawn. 

5.3.3.2 Draw Initiation Criteria. Begin the 

first-hour rating test by starting a draw on the 

storage-type water heater. After completion 

of this first draw, initiate successive draws 

based on the following criteria. For gas-fired 

and oil-fired water heaters, initiate 

successive draws when the temperature 

controller acts to reduce the supply of fuel 

to the main burner. For electric water heaters 

having a single element or multiple elements 

that all operate simultaneously, initiate 

successive draws when the temperature 

controller acts to reduce the electrical input 

supplied to the element(s). For electric water 

heaters having two or more elements that do 

not operate simultaneously, initiate 

successive draws when the applicable 

temperature controller acts to reduce the 

electrical input to the energized element 

located vertically highest in the storage tank. 

For heat pump water heaters that do not use 

supplemental, resistive heating, initiate 

successive draws immediately after the 

electrical input to the compressor is reduced 

by the action of the water heater’s 

temperature controller. For heat pump water 

heaters that use supplemental resistive 

heating, initiate successive draws 

immediately after the electrical input to the 

first of either the compressor or the vertically 

highest resistive element is reduced by the 

action of the applicable water heater 

temperature controller. This draw initiation 

criterion for heat pump water heaters that use 

supplemental resistive heating, however, 

shall only apply when the water located 

above the thermostat at cut-out is heated to 

125 °F ± 5 °F (51.7 °C ± 2.8 °C). If this 


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40572 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

criterion is not met, then the next draw 

should be initiated once the heat pump 

compressor cuts out. 

5.3.3.3 Test Sequence. Establish normal 

water heater operation. If the water heater is 

not presently operating, initiate a draw. The 

draw may be terminated any time after cutin occurs. After cut-out occurs (i.e., all 

temperature controllers are satisfied), record 

the internal storage tank temperature at each 

sensor described in section 4.5 of this 

appendix every one minute, and determine 

the mean tank temperature by averaging the 

values from these sensors. 

Initiate a draw after a maximum mean tank 

temperature (the maximum of the mean 

temperatures of the individual sensors) has 

been observed following a cut-out. Record 

the time when the draw is initiated and 

designate it as an elapsed time of zero (t* = 

0). (The superscript * is used to denote 

variables pertaining to the first-hour rating 

test). Record the outlet water temperature 

beginning 15 seconds after the draw is 

initiated and at 5-second intervals thereafter 

until the draw is terminated. Determine the 

maximum outlet temperature that occurs 

during this first draw and record it as T*max,1. 

For the duration of this first draw and all 

successive draws, in addition, monitor the 

inlet temperature to the water heater to 

ensure that the required 58 °F ± 2 °F (14.4 °C 

± 1.1 °C) test condition is met. Terminate the 

hot water draw when the outlet temperature 

decreases to T*max,1 ¥ 15 °F (T*max,1 ¥ 8.3 

°C). (Note, if the outlet temperature does not 

decrease to T*max,1 ¥ 15 °F (T*max,1 ¥ 8.3 °C) 

during the draw, then hot water would be 

drawn continuously for the duration of the 

test. In this instance, the test would end 

when the temperature decreases to T*max,1¥ 

15 °F (T*max,1 ¥ 8.3 °C) after the electrical 

power and/or fuel supplied to the water 

heater is shut off, as described in the 

following paragraphs.) Record this 

temperature as T*min,1. Following draw 

termination, determine the average outlet 

water temperature and the mass or volume 

removed during this first draw and record 

them as T*del,i and M*1 or V*1, respectively. 

Initiate a second and, if applicable, 

successive draw(s) each time the applicable 

draw initiation criteria described in section 

5.3.3.2 are satisfied. As required for the first 

draw, record the outlet water temperature 15 

seconds after initiating each draw and at 5- 

second intervals thereafter until the draw is 

terminated. Determine the maximum outlet 

temperature that occurs during each draw 

and record it as T*max,i, where the subscript 

i refers to the draw number. Terminate each 

hot water draw when the outlet temperature 

decreases to T*max,i ¥ 15 °F (T*max,i ¥ 8.3 

°C). Record this temperature as T*min,i. 

Calculate and record the average outlet 

temperature and the mass or volume 

removed during each draw (T*del,i and M*i or 

V*i, respectively). Continue this sequence of 

draw and recovery until one hour after the 

start of the test, then shut off the electrical 

power and/or fuel supplied to the water 

heater. 

If a draw is occurring at one hour from the 

start of the test, continue this draw until the 

outlet temperature decreases to T*max,n ¥ 15 

°F (T*max,n ¥ 8.3 °C), at which time the draw 

shall be immediately terminated. (The 

subscript n shall be used to denote 

measurements associated with the final 

draw.) If a draw is not occurring one hour 

after the start of the test, initiate a final draw 

at one hour, regardless of whether the criteria 

described in section 5.3.3.2 of this appendix 

are satisfied. This draw shall proceed for a 

minimum of 30 seconds and shall terminate 

when the outlet temperature first indicates a 

value less than or equal to the cut-off 

temperature used for the previous draw 

(T*min,n¥1). If an outlet temperature greater 

than T*min,n¥1 is not measured within 30 

seconds of initiation of the draw, zero 

additional credit shall be given towards firsthour rating (i.e., M*n = 0 or V*n = 0) based 

on the final draw. After the final draw is 

terminated, calculate and record the average 

outlet temperature and the mass or volume 

removed during the final draw (T*del,n and 

M*n or V*n, respectively). 

5.4 24-Hour Simulated Use Test. 

5.4.1 Selection of Draw Pattern. The 

water heater will be tested under a draw 

profile that depends upon the first-hour 

rating obtained following the test prescribed 

in section 5.3.3 of this appendix, or the 

maximum GPM rating obtained following the 

test prescribed in section 5.3.2 of this 

appendix, whichever is applicable. For water 

heaters that have been tested according to the 

first-hour rating procedure, one of four 

different patterns shall be applied based on 

the measured first-hour rating, as shown in 

Table I of this section. For water heater that 

have been tested according to the maximum 

GPM rating procedure, one of four different 

patterns shall be applied based on the 

maximum GPM, as shown in Table II of this 

section. 

TABLE I—DRAW PATTERN TO BE USED BASED ON FIRST-HOUR RATING

First-hour rating greater than or equal to: ... and first-hour rating less than: Draw pattern to be used in simulated-use test 

0 gallons .................................................................... 18 gallons .................................................................. Very-Small-Usage (Table III.1). 

18 gallons .................................................................. 51 gallons .................................................................. Low-Usage (Table III.2). 

51 gallons .................................................................. 75 gallons .................................................................. Medium-Usage (Table III.3). 

75 gallons .................................................................. No upper limit ............................................................ High-Usage (Table III.4). 

TABLE II—DRAW PATTERN TO BE USED BASED ON MAXIMUM GPM RATING

Maximum GPM rating greater than or equal to: and maximum GPM rating less than: Draw pattern to be used in simulated-use test 

0 gallons/minute ........................................................ 1.7 gallons/minute ..................................................... Very-Small-Usage (Table III.1). 

1.7 gallons/minute ..................................................... 2.8 gallons/minute ..................................................... Low-Usage (Table III.2). 

2.8 gallons/minute ..................................................... 4 gallons/minute ........................................................ Medium-Usage (Table III.3). 

4 gallons/minute ........................................................ No upper limit ............................................................ High-Usage (Table III.4). 

The draw patterns are provided in Tables 

III.1 through III.4 in section 5.5 of this 

appendix. Use the appropriate draw pattern 

when conducting the test sequence provided 

in section 5.4.2 of this appendix for water 

heaters with rated storage volumes greater 

than or equal to 2 gallons or section 5.4.3 of 

this appendix for water heaters with rated 

storage volumes less than 2 gallons. 

5.4.2 Test Sequence for Water Heaters 

with Rated Storage Volumes Greater Than or 

Equal to 2 Gallons. If the water heater is 

turned off, fill the water heater with supply 

water and maintain supply water pressure as 

described in section 2.6 of this appendix. 

Turn on the water heater and associated heat 

pump unit, if present. If turned on in this 

fashion, the soak-in period described in 

section 5.2.4 of this appendix shall be 

implemented. If the water heater has 

undergone a first-hour rating test prior to 

conduct of the simulated-use test, allow the 

water heater to fully recover after completion 

of that test such that the main burner, heating 

elements, or heat pump compressor of the 

water heater are no longer raising the 

temperature of the stored water. In all cases, 

the water heater shall sit idle for 1 hour prior 

to the start of the 24-hour test; during which 

time no water is drawn from the unit and 

there is no energy input to the main heating 

elements, heat pump compressor, and/or 

burners. At the end of this period, the 24- 

hour simulated-use test will begin. 

At the start of the 24-hour test, record the 

mean tank temperature (T0), and the 

electrical and/or fuel measurement readings, 

as appropriate. Begin the 24-hour simulated 

use test by withdrawing the volume specified 


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in the appropriate table in section 5.5 of this 

appendix (i.e., Table III.1, Table III.2, Table 

III.3, or Table III.4, depending on the firsthour rating or maximum GPM rating) for the 

first draw at the flow rate specified in the 

applicable table. Record the time when this 

first draw is initiated and assign it as the test 

elapsed time (t) of zero (0). Record the 

average storage tank and ambient 

temperature every minute throughout the 24- 

hour simulated-use test. At the elapsed times 

specified in the applicable draw pattern table 

in section 5.5 of this appendix for a 

particular draw pattern, initiate additional 

draws pursuant to the draw pattern, 

removing the volume of hot water at the 

prescribed flow rate specified by the table. 

The maximum allowable deviation from the 

specified volume of water removed for any 

single draw taken at a nominal flow rate of 

1 GPM or 1.7 GPM is ±0.1 gallons (±0.4 

liters). The maximum allowable deviation 

from the specified volume of water removed 

for any single draw taken at a nominal flow 

rate of 3 GPM is ±0.25 gallons (0.9 liters). The 

quantity of water withdrawn during the last 

draw shall be increased or decreased as 

necessary such that the total volume of water 

withdrawn equals the prescribed daily 

amount for that draw pattern ±1.0 gallon 

(±3.8 liters). If this adjustment to the volume 

drawn during the last draw results in no 

draw taking place, the test is considered 

invalid. 

All draws during the 24-hour simulateduse test shall be made at the flow rates 

specified in the applicable draw pattern table 

in section 5.5 of this appendix, within a 

tolerance of ±0.25 gallons per minute (±0. 9 

liters per minute). Measurements of the inlet 

and outlet temperatures shall be made 5 

seconds after the draw is initiated and at 

every subsequent 3-second interval 

throughout the duration of each draw. 

Calculate and record the mean of the hot 

water discharge temperature and the cold 

water inlet temperature for each draw Tdel,i

and Tin,i). Determine and record the net mass 

or volume removed (Mi or Vi), as appropriate, 

after each draw. 

At the end of the first recovery period 

following the first draw, which may extend 

beyond subsequent draws, record the 

maximum mean tank temperature observed 

after cut-out, Tmax,1, and the energy 

consumed by an electric resistance, gas, or 

oil-fired water heater (including electrical 

energy), from the beginning of the test, Qr. 

For heat pump water heaters, the total energy 

consumed during the first recovery by the 

heat pump (including compressor, fan, 

controls, pump, etc.) and, if applicable, by 

the resistive element(s) shall be recorded as 

Qr. 

The start of the portion of the test during 

which the standby loss coefficient is 

determined depends upon whether the unit 

has fully recovered from the first draw 

cluster. If a recovery is occurring at or within 

five minutes of the end of the final draw in 

the first draw cluster, as identified in the 

applicable draw pattern table in section 5.5 

of this appendix, then the standby period 

starts when a maximum average tank 

temperature is observed starting five minutes 

after the end of the recovery period that 

follows that draw. If a recovery does not 

occur at or within five minutes of the end of 

the final draw in the first draw cluster, as 

identified in the applicable draw pattern 

table in section 5.5 of this appendix, then the 

standby period starts five minutes after the 

end of that draw. Determine and record the 

total electrical energy and/or fossil fuel 

consumed from the beginning of the test to 

the start of the standby period, Qsu,0. 

In preparation for determining the energy 

consumed during standby, record the reading 

given on the electrical energy (watt-hour) 

meter, the gas meter, and/or the scale used 

to determine oil consumption, as 

appropriate. Record the mean tank 

temperature at the start of the standby period 

as Tsu,0. At 1-minute intervals, record the 

mean tank temperature and the electric and/ 

or fuel instrument readings until the next 

draw is initiated. Just prior to initiation of the 

next draw, record the mean tank temperature 

as Tsu,f. If the water heater is undergoing 

recovery when the next draw is initiated, 

record the mean tank temperature Tsu,f at the 

minute prior to the start of the recovery. The 

time at which this value occurs is the end of 

the standby period. Determine the total 

electrical energy and/or fossil fuel energy 

consumption from the beginning of the test 

to this time and record as Qsu,f. Record the 

time interval between the start of the standby 

period and the end of the standby period as 

tstby,1. Record the time during which water is 

not being withdrawn from the water heater 

during the entire 24-hour period as tstby,2. 

In the event that the recovery period 

continues from the end of the last draw of the 

first draw cluster until the subsequent draw, 

the standby period will start after the end of 

the first recovery period after the last draw 

of the simulated-use test, when the 

temperature reaches the maximum average 

tank temperature, though no sooner than five 

minutes after the end of this recovery period. 

The standby period shall last eight hours, so 

testing will extend beyond the 24-hour 

duration of the simulated-use test. Determine 

and record the total electrical energy and/or 

fossil fuel consumed from the beginning of 

the simulated-use test to the start of the 8- 

hour standby period, Qsu,0. In preparation for 

determining the energy consumed during 

standby, record the reading(s) given on the 

electrical energy (watt-hour) meter, the gas 

meter, and/or the scale used to determine oil 

consumption, as appropriate. Record the 

mean tank temperature at the start of the 

standby period as Tsu,0. Record the mean tank 

temperature, the ambient temperature, and 

the electric and/or fuel instrument readings 

until the end of the 8 hour period. Record the 

mean tank temperature at the end of the 8 

hour standby period as Tsu,f. If the water 

heater is undergoing recovery at the end of 

the standby period, record the mean tank 

temperature Tsu,f at the minute prior to the 

start of the recovery, which will mark the end 

of the standby period. Determine the total 

electrical energy and/or fossil fuel energy 

consumption from the beginning of the test 

to the end of the standby period and record 

this value as Qsu,f. Record the time interval 

between the start of the standby period and 

the end of the standby period as tstby,1. 

Following the final draw of the prescribed 

draw pattern and subsequent recovery, allow 

the water heater to remain in the standby 

mode until exactly 24 hours have elapsed 

since the start of the simulated-use test (i.e., 

since t = 0). During the last hour of the 

simulated-use test, power to the main burner, 

heating element, or compressor shall be 

disabled. At 24 hours, record the reading 

given by the gas meter, oil meter, and/or the 

electrical energy meter as appropriate. 

Determine the fossil fuel and/or electrical 

energy consumed during the entire 24-hour 

simulated-use test and designate the quantity 

as Q. 

5.4.3 Test Sequence for Water Heaters 

With Rated Storage Volume Less Than 2 

Gallons. 

Establish normal operation with the 

discharge water temperature at 125 °F ± 5 °F 

(51.7 °C ± 2.8 °C) and set the flow rate as 

determined in section 5.2 of this appendix. 

Prior to commencement of the 24-hour 

simulated-use test, the unit shall remain in 

an idle state in which controls are active but 

no water is drawn through the unit for a 

period of one hour. With no draw occurring, 

record the reading given by the gas meter 

and/or the electrical energy meter as 

appropriate. Begin the 24-hour simulated-use 

test by withdrawing the volume specified in 

Tables III.1 through III.4 of section 5.5 of this 

appendix for the first draw at the flow rate 

specified. Record the time when this first 

draw is initiated and designate it as an 

elapsed time, t, of 0. At the elapsed times 

specified in Tables III.1 through III.4 for a 

particular draw pattern, initiate additional 

draws, removing the volume of hot water at 

the prescribed flow rate specified in Tables 

III.1 through III.4. The maximum allowable 

deviation from the specified volume of water 

removed for any single draw taken at a 

nominal flow rate less than or equal to 1.7 

GPM (6.4 L/min) is ±0.1 gallons (±0.4 liters). 

The maximum allowable deviation from the 

specified volume of water removed for any 

single draw taken at a nominal flow rate of 

3 GPM (11.4 L/min) is ±0.25 gallons (0.9 

liters). The quantity of water drawn during 

the final draw shall be increased or decreased 

as necessary such that the total volume of 

water withdrawn equals the prescribed daily 

amount for that draw pattern ±1.0 gallon 

(±3.8 liters). If this adjustment to the volume 

drawn in the last draw results in no draw 

taking place, the test is considered invalid. 

Measurements of the inlet and outlet water 

temperatures shall be made 5 seconds after 

the draw is initiated and at every 3-second 

interval thereafter throughout the duration of 

the draw. Calculate the mean of the hot water 

discharge temperature and the cold water 

inlet temperature for each draw. Record the 

mass of the withdrawn water or the water 

meter reading, as appropriate, after each 

draw. At the end of the recovery period 

following the first draw, determine and 

record the fossil fuel and/or electrical energy 

consumed, Qr. Following the final draw and 

subsequent recovery, allow the water heater 

to remain in the standby mode until exactly 

24 hours have elapsed since the start of the 

test (i.e., since t = 0). At 24 hours, record the 

reading given by the gas meter, oil meter, 

and/or the electrical energy meter, as 

appropriate. Determine the fossil fuel and/or 

electrical energy consumed during the entire 


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24-hour simulated-use test and designate the 

quantity as Q. 

5.5 Draw Patterns. The draw patterns to 

be imposed during 24-hour simulated-use 

tests are provided in Tables III.1 through 

III.4. Subject each water heater under test to 

one of these draw patterns based on its firsthour rating or maximum GPM rating, as 

discussed in section 5.4.1 of this appendix. 

Each draw pattern specifies the elapsed time 

in hours and minutes during the 24-hour test 

when a draw is to commence, the total 

volume of water in gallons (liters) that is to 

be removed during each draw, and the flow 

rate at which each draw is to be taken, in 

gallons (liters) per minute. 

TABLE III.1—VERY-SMALL-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (L)] 

Flow Rate ** 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 2.0 (7.6) 1 (3.8) 

2 * ......................................................................................................................... 1:00 1.0 (3.8) 1 (3.8) 

3 * ......................................................................................................................... 1:05 0.5 (1.9) 1 (3.8) 

4 * ......................................................................................................................... 1:10 0.5 (1.9) 1 (3.8) 

5 * ......................................................................................................................... 1:15 0.5 (1.9) 1 (3.8) 

6 ........................................................................................................................... 8:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 8:15 2.0 (7.6) 1 (3.8) 

8 ........................................................................................................................... 9:00 1.5 (5.7) 1 (3.8) 

9 ........................................................................................................................... 9:15 1.0 (3.8) 1 (3.8) 

Total Volume Drawn Per Day: 10 gallons (38 L) 

* Denotes draws in first draw cluster. 

** Should the water heater have a maximum GPM rating less than 1 GPM (3.8 L/min), then all draws shall be implemented at a flow rate equal 

to the rated maximum GPM. 

TABLE III.2—LOW-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 15.0 (56.8) 1.7 (6.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 1:00 1.0 (3.8) 1 (3.8) 

4 ........................................................................................................................... 10:30 6.0 (22.7) 1.7 (6.4) 

5 ........................................................................................................................... 11:30 4.0 (15.1) 1.7 (6.4) 

6 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

10 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

11 ......................................................................................................................... 17:00 3.0 (11.4) 1.7 (6.4) 

Total Volume Drawn Per Day: 38 gallons (144 L) 

* Denotes draws in first draw cluster. 

TABLE III.3—MEDIUM-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 15.0 (56.8) 1.7 (6.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 1:40 9.0 (34.1) 1.7 (6.4) 

4 ........................................................................................................................... 10:30 9.0 (34.1) 1.7 (6.4) 

5 ........................................................................................................................... 11:30 5.0 (18.9) 1.7 (6.4) 

6 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

7 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 16:00 1.0 (3.8) 1 (3.8) 

10 ......................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

11 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

12 ......................................................................................................................... 17:00 7.0 (26.5) 1.7 (6.4) 

Total Volume Drawn Per Day: 55 gallons (208 L) 

* Denotes draws in first draw cluster. 


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TABLE III.4—HIGH-USAGE DRAW PATTERN

Draw No. Time during test 

[hh:mm] 

Volume 

[gallons (liters)] 

Flow rate 

[GPM (L/min)] 

1 * ......................................................................................................................... 0:00 27.0 (102) 3 (11.4) 

2 * ......................................................................................................................... 0:30 2.0 (7.6) 1 (3.8) 

3 * ......................................................................................................................... 0:40 1.0 (3.8) 1 (3.8) 

4 * ......................................................................................................................... 1:40 9.0 (34.1) 1.7 (6.4) 

5 ........................................................................................................................... 10:30 15.0 (56.8) 3 (11.4) 

6 ........................................................................................................................... 11:30 5.0 (18.9) 1.7 (6.4) 

7 ........................................................................................................................... 12:00 1.0 (3.8) 1 (3.8) 

8 ........................................................................................................................... 12:45 1.0 (3.8) 1 (3.8) 

9 ........................................................................................................................... 12:50 1.0 (3.8) 1 (3.8) 

10 ......................................................................................................................... 16:00 2.0 (7.6) 1 (3.8) 

11 ......................................................................................................................... 16:15 2.0 (7.6) 1 (3.8) 

12 ......................................................................................................................... 16:30 2.0 (7.6) 1.7 (6.4) 

13 ......................................................................................................................... 16:45 2.0 (7.6) 1.7 (6.4) 

14 ......................................................................................................................... 17:00 14.0 (53.0) 3 (11.4) 

Total Volume Drawn Per Day: 84 gallons (318 L) 

* Denotes draws in first draw cluster. 

6. Computations 

6.1 First-Hour Rating Computation. For 

the case in which the final draw is initiated 

at or prior to one hour from the start of the 

test, the first-hour rating, Fhr, shall be 

computed using, 

Where: 

n = the number of draws that are completed 

during the first-hour rating test. 

V*i = the volume of water removed during 

the ith draw of the first-hour rating test, 

gal (L) or, if the mass of water is being 

measured, 

Where: 

M*i = the mass of water removed during the 

ith draw of the first-hour rating test, lb 

(kg). 

r = the water density corresponding to the 

average outlet temperature measured 

during the ith draw, (T*del,i), lb/gal (kg/ 

L). 

For the case in which a draw is not in 

progress at one hour from the start of the test 

and a final draw is imposed at the elapsed 

time of one hour, the first-hour rating shall 

be calculated using 

where n and V*i are the same quantities as 

defined above, and 

V*n = the volume of water drawn during the 

nth (final) draw of the first-hour rating 

test, gal (L). 

T*del,n¥1 = the average water outlet 

temperature measured during the 

(n¥1)th draw of the first-hour rating test, 

°F (°C). 

T*del,n = the average water outlet temperature 

measured during the nth (final) draw of 

the first-hour rating test, °F (°C). 

T*min,n¥1 = the minimum water outlet 

temperature measured during the 

(n¥1)th draw of the first-hour rating test, 

°F (°C). 

6.2 Maximum GPM (L/min) Rating 

Computation. Compute the maximum GPM 

(L/min) rating, Fmax, as: 


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Where: 

M10m = the mass of water collected during the 

10-minute test, lb (kg). 

Tdel = the average delivery temperature, °F 

(°C). 

Tin = the average inlet temperature, °F (°C). 

r = the density of water at the average 

delivery temperature, lb/gal (kg/L). 

If a water meter is used, the maximum 

GPM (L/min) rating is computed as: 

Where: 

V10m = the volume of water measured during 

the 10-minute test, gal (L). 

Tdel = as defined in this section. 

Tin = as defined in this section. 

6.3 Computations for Water Heaters with 

a Rated Storage Volume Greater Than or 

Equal to 2 Gallons. 

6.3.1 Storage Tank Capacity. The storage 

tank capacity, Vst, is computed as follows: 

Where: 

Vst = the storage capacity of the water heater, 

gal (L) 

Wf = the weight of the storage tank when 

completely filled with water, lb (kg) 

Wt = the (tare) weight of the storage tank 

when completely empty, lb (kg) 

r = the density of water used to fill the tank 

measured at the temperature of the 

water, lb/gal (kg/L) 

6.3.2 Recovery Efficiency. The recovery 

efficiency for gas, oil, and heat pump storagetype water heaters, hr, is computed as: 

Where: 

M1 = total mass removed from the start of the 

24-hour simulated-use test to the end of 

the first recovery period, lb (kg), or, if the 

volume of water is being measured, 

M1 = V1r1

Where: 

V1 = total volume removed from the start of 

the 24-hour simulated-use test to the end 

of the first recovery period, gal (L). 

r1 = density of the water at the water 

temperature measured at the point where 

the flow volume is measured, lb/gal (kg/ 

L). 

Cp1 = specific heat of the withdrawn water 

evaluated at (Tdel,1 + Tin,1)/2, Btu/(lb·°F) 

(kJ/(kg·°C)) 

Tdel,1 = average water outlet temperature 

measured during the draws from the start 

of the 24-hour simulated-use test to the 

end of the first recovery period, °F (°C). 

Tin,1 = average water inlet temperature 

measured during the draws from the start 


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of the 24-hour simulated-use test to the 

end of the first recovery period, °F (°C). 

Vst = as defined in section 6.3.1. 

r2 = density of stored hot water evaluated at 

(Tmax,1 + To)/2, lb/gal (kg/L). 

Cp2 = specific heat of stored hot water 

evaluated at (Tmax,1 + To)/2, Btu/(lb·°F) 

(kJ/(kg·°C). 

Tmax,1 = maximum mean tank temperature 

recorded after cut-out following the first 

recovery of the 24-hour simulated use 

test, °F (°C). 

To = maximum mean tank temperature 

recorded prior to the first draw of the 24- 

hour simulated-use test, °F (°C). 

Qr = the total energy used by the water heater 

between cut-out prior to the first draw 

and cut-out following the first recovery 

period, including auxiliary energy such 

as pilot lights, pumps, fans, etc., Btu (kJ). 

(Electrical auxiliary energy shall be 

converted to thermal energy using the 

following conversion: 1 kWh = 3412 

Btu). 

The recovery efficiency for electric water 

heaters with immersed heating elements is 

assumed to be 98 percent. 

6.3.3 Hourly Standby Losses. The energy 

consumed as part of the standby loss test of 

the 24-hour simulated-use test, Qstby, is 

computed as: 

Qstby = Qsu,f - Qsu,o

Where: 

Qsu,0 = cumulative energy consumption of 

the water heater from the start of the 24-hour 

simulated-use test to the time at which the 

maximum mean tank temperature is attained 

starting five minutes after the recovery 

following the end of the first draw cluster, 

Btu (kJ). 

Qsu,f = cumulative energy consumption of 

the water heater from the start of the 24-hour 

simulated-use test to the minute prior to the 

start of the draw following the end of the first 

draw cluster or the minute prior to a recovery 

occurring at the start of the draw following 

the end of the first draw cluster, Btu (kJ). 

The hourly standby energy losses are 

computed as: 

Where: 

Qhr = the hourly standby energy losses of the 

water heater, Btu/h (kJ/h). 

Vst = as defined in section 6.3.1 of this 

appendix. 

r = density of stored hot water, (Tsu,f + Tsu,0)/ 

2, lb/gal (kg/L). 

Cp = specific heat of the stored water, (Tsu,f

+ Tsu,0)/2, Btu/(lb·F), (kJ/(kg·K)) 

Tsu,f = the mean tank temperature observed 

at the minute prior to the start of the 

draw following the first draw cluster or 

the minute prior to a recovery occurring 

at the start of the draw following the end 

of the first draw cluster, °F (°C). 

Tsu,0 = the maximum mean tank temperature 

observed starting five minutes after the 

first recovery following the final draw of 

the first draw cluster, °F (°C). 

hr = as defined in section 6.3.2 of this 

appendix. 

tstby,1 = elapsed time between the time at 

which the maximum mean tank 

temperature is observed starting five 

minutes after recovery from the first 

draw cluster and the minute prior to the 

start of the first draw following the end 

of the first draw cluster of the 24-hour 

simulated-use test or the minute prior to 

a recovery occurring at the start of the 

draw following the end of the first draw 

cluster, h. 

The standby heat loss coefficient for the 

tank is computed as: 

Where: 

UA = standby heat loss coefficient of the 

storage tank, Btu/(h·°F), (kJ/(h·°C). 

Tt,stby,1 = overall average storage tank 

temperature between the time when the 

maximum mean tank temperature is 

observed starting five minutes after cutout following the first draw cluster and 

the minute prior to commencement of 

the next draw following the first draw 

cluster of the 24-hour simulated-use test 

or the minute prior to a recovery 

occurring at the start of the draw 

following the end of the first draw 

cluster, °F (°C). 

Ta,stby,1 = overall average ambient temperature 

between the time when the maximum 

mean tank temperature is observed 

starting five minutes after cut-out 

following the first draw cluster and the 

minute prior to commencement of the 

next draw following the first draw 

cluster of the 24-hour simulated-use test 

or the minute prior to a recovery 

occurring at the start of the draw 

following the end of the first draw 

cluster, °F (°C). 

6.3.4 Daily Water Heating Energy 

Consumption. The daily water heating energy 

consumption, Qd, is computed as: 

Where: 

Q = Qf + Qe = total energy used by the water 

heater during the 24-hour simulated-use 

test, including auxiliary energy such as 

pilot lights, pumps, fans, etc., Btu (kJ). 

(Electrical energy shall be converted to 

thermal energy using the following 

conversion: 1kWh = 3412 Btu.) 

Qf = total fossil fuel energy used by the water 

heater during the 24-hour simulated-use 

test, Btu (kJ). 

Qe = total electrical energy used during the 

24-hour simulated-use test, Btu (kJ). 

Vst = as defined in section 6.3.1 of this 

appendix. 

r = density of the stored hot water, evaluated 

at (T24 + T0)/2, lb/gal (kg/L) 

Cp = specific heat of the stored water, 

evaluated at (T24 + T0)/2, Btu/(lb·F), (kJ/ 

(kg·K)). 

T24 = mean tank temperature at the end of the 

24-hour simulated-use test, °F (°C). 

T0 = mean tank temperature at the beginning 

of the 24-hour simulated-use test, 

recorded one minute before the first 

draw is initiated, °F (°C). 

hr = as defined in section 6.3.2 of this 

appendix. 

6.3.5 Adjusted Daily Water Heating 

Energy Consumption. The adjusted daily 

water heating energy consumption, Qda, takes 

into account that the ambient temperature 

may differ from the nominal value of 67.5 °F 

(19.7°C) due to the allowable variation in 

surrounding ambient temperature of 65 °F 

(18.3 °C) to 70 °C (21.1°C). The adjusted daily 

water heating energy consumption is 

computed as: 


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Where: 

Qda = the adjusted daily water heating energy 

consumption, Btu (kJ). 

Qd = as defined in section 6.3.4 of this 

appendix. 

Ta,stby,2 = the average ambient temperature 

during the total standby portion, tstby,2, of 

the 24-hour simulated-use test, °F (°C). 

UA = as defined in section 6.3.3 of this 

appendix. 

tstby,2 = the number of hours during the 24- 

hour simulated-use test when water is 

not being withdrawn from the water 

heater. 

A modification is also needed to take into 

account that the temperature difference 

between the outlet water temperature and 

supply water temperature may not be 

equivalent to the nominal value of 67 °F 

(125 °F–58 °F) or 37.3 °C (51.7 °C–14.4 °C). 

The following equations adjust the 

experimental data to a nominal 67 °F 

(37.3 °C) temperature rise. 

The energy used to heat water, Btu/day (kJ/ 

day), may be computed as: 

Where: 

N = total number of draws in the draw 

pattern. 

Mi = the mass withdrawn for the ith draw (i 

= 1 to N), lb (kg) 

Cpi = the specific heat of the water of the ith 

draw evaluated at (Tdel,i + Tin,i)/2, Btu/

(lb·°F) (kJ/(kg·°C)). 

Tdel,i = the average water outlet temperature 

measured during the ith draw (i = 1 to 

N), °F (°C). 

Tin,i = the average water inlet temperature 

measured during the ith draw (i = 1 to 

N), °F (°C). 

hr = as defined in section 6.3.2 of this 

appendix. 

The energy required to heat the same 

quantity of water over a 67 °F (37.3 °C) 

temperature rise, Btu/day (kJ/day), is: 

The difference between these two values is: 

QHWD = QHW,67 °F ¥ QHW

or QHWD = QHW,37.3°C ¥ QHW

This difference (QHWD) must be added to the 

adjusted daily water heating energy 

consumption value. Thus, the daily energy 

consumption value which takes into account 

that the ambient temperature may not be 67.5 

°F (19.7 °C) and that the temperature rise 

across the storage tank may not be 67 °F (37.3 

°C) is: 

Qdm = Qda + QHWD

6.3.6 Uniform Energy Factor. The 

uniform energy factor, UEF, is computed as: 

Where: 

N = total number of draws in the draw 

pattern 

Qdm = the modified daily water heating 

energy consumption as computed in 

accordance with section 6.3.5 of this 

appendix, Btu (kJ) 

Mi = the mass withdrawn for the ith draw (i 

= 1 to N), lb (kg) 

Cpi = the specific heat of the water of the ith 

draw, evaluated at (125 °F + 58 °F)/2 = 


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91.5 °F ((51.7 °C + 14.4 °C)/2 = 33 °C), 

Btu/(lb· °F) (kJ/(kg· °C)). 

6.3.7 Annual Energy Consumption. The 

annual energy consumption for water heaters 

with rated storage volumes greater than or 

equal to 2 gallons is computed as: 

Where: 

UEF = the uniform energy factor as computed 

in accordance with section 6.3.6 of this 

appendix 

365 = the number of days in a year 

V = the volume of hot water drawn during 

the applicable draw pattern, gallons 

= 10 for the very-small-usage draw pattern 

= 38 for the low-usage draw pattern 

= 55 for the medium-usage draw pattern 

= 84 for high-usage draw pattern 

r = 8.24 lbm/gallon, the density of water at 

125 °F 

CP = 1.00 Btu/lbm °F, the specific heat of 

water at 91.5 °F 

67 = the nominal temperature difference 

between inlet and outlet water 

6.3.8 Annual Electrical Energy 

Consumption. The annual electrical energy 

consumption in kilowatt-hours for water 

heaters with rated storage volumes greater 

than or equal to 2 gallons, Eannual,e, is 

computed as: 

Eannual,e = Eannual*(Qe/Q)/3412 

Where: 

Eannual = the annual energy consumption as 

determined in accordance with section 

6.3.7, Btu (kJ) 

Qe = the daily electrical energy consumption 

as defined in section 6.3.4 of this 

appendix, Btu (kJ). 

Q = total energy used by the water heater 

during the 24-hour simulated-use test in 

accordance with section 6.3.4 of this 

appendix, Btu (kJ) 

3412 = conversion factor from Btu to kWh 

6.3.9 Annual Fossil Fuel Energy 

Consumption. The annual fossil fuel energy 

consumption for water heaters with rated 

storage volumes greater than or equal to 2 

gallons, Eannual,f, is computed as: 

Eannual,f = Eannual ¥ (Eannual,e × 3412) 

Where: 

Eannual = the annual energy consumption as 

determined in accordance with section 

6.3.7 of this appendix, Btu (kJ) 

Eannual,e = the annual electrical energy 

consumption as determined in 

accordance with section 6.3.8 of this 

appendix, kWh 

3412 = conversion factor from kWh to Btu 

6.4 Computations for Water Heaters With 

Rated Storage Volume Less Than 2 Gallons. 

6.4.1 Recovery Efficiency. The recovery 

efficiency, hr, is computed as: 

Where: 

M1 = total mass removed during the first 

draw of the 24-hour simulated-use test, 

lb (kg), or, if the volume of water is being 

measured, M1 = V1 · r 

Where: 

V1 = total volume removed during the first 

draw of the 24-hour simulated-use test, 

gal (L). 

r = density of the water at the water 

temperature measured at the point where 

the flow volume is measured, lb/gal 

(kg/L). 

Cp1 = specific heat of the withdrawn water, 

(Tdel,1 û Tin,1)/2, Btu/(lb · °F) (kJ/(kg · 

°C)). 

Tdel,1 = average water outlet temperature 

measured during the first draw of the 24- 

hour simulated-use test, °F (°C). 

Tin,1 = average water inlet temperature 

measured during the first draw of the 24- 

hour simulated-use test, °F (°C). 

Qr = the total energy used by the water heater 

between cut-out prior to the first draw 

and cut-out following the first draw, 

including auxiliary energy such as pilot 

lights, pumps, fans, etc., Btu (kJ). 

(Electrical auxiliary energy shall be 

converted to thermal energy using the 

following conversion: 1 kWh = 3412 

Btu.) 

6.4.2 Daily Water Heating Energy 

Consumption. The daily water heating energy 

consumption, Qd, is computed as: 

Qd = Q 

Where: 

Q = Qf + Qe = the energy used by the water 

heater during the 24-hour simulated-use 

test. 

Qf = total fossil fuel energy used by the water 

heater during the 24-hour simulated-use 

test, Btu (kJ). 

Qe = total electrical energy used during the 

24-hour simulated-use test, Btu (kJ). 

A modification is needed to take into 

account that the temperature difference 

between the outlet water temperature and 

supply water temperature may not be 

equivalent to the nominal value of 67 °F (125 

°F–58 °F) or 37.3 °C (51.7 °C–14.4 °C). The 

following equations adjust the experimental 

data to a nominal 67 °F (37.3 °C) temperature 

rise. 

The energy used to heat water may be 

computed as: 

Where: 

N = total number of draws in the draw 

pattern 

Mi = the mass withdrawn for the ith draw 

(i = 1 to N), lb (kg) 

Cpi = the specific heat of the water of the ith 

draw evaluated at (Tdel,i + Tin,i)/2, Btu/(lb 

· °F) (kJ/(kg · °C)). 

Tdel,i = the average water outlet temperature 

measured during the ith draw (i = 1 to 

N), °F (°C). 

Tin,i = the average water inlet temperature 

measured during the ith draw (i = 1 to 

N), °F (°C). 

hr = as defined in section 6.4.1 of this 

appendix. 

The energy required to heat the same 

quantity of water over a 67 °F (37.3 °C) 

temperature rise is: 


tkelley on DSK3SPTVN1PROD with RULES2ER11JY14.083</GPH> ER11JY14.084</GPH> ER11JY14.085</GPH> ER11JY14.086</GPH>
40580 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

Where: 

N = total number of draws in the draw 

pattern 

Mi = the mass withdrawn during the ith 

draw, lb (kg) 

Cpi = the specific heat of water of the ith 

draw, Btu/(lb · °F) (kJ/(kg · °C)) 

hr = as defined in section 6.4.1 of this 

appendix. 

The difference between these two values is: This difference (QHWD) must be added to the 

daily water heating energy consumption 

value. Thus, the daily energy consumption 

value, which takes into account that the 

temperature rise across the water heater may 

not be 67 °F (37.3 °C), is: 

Qdm = Qd + QHWD

6.4.3 Uniform Energy Factor. The 

uniform energy factor, UEF, is computed as: 

Where: 

N = total number of draws in the draw 

pattern 

Qdm = the modified daily water heating 

energy consumption as computed in 

accordance with section 6.4.2 of this 

appendix, Btu (kJ) 

Mi = the mass withdrawn for the ith draw 

(i = 1 to N), lb (kg) 

Cpi = the specific heat of the water at the ith 

draw, evaluated at (125 °F + 58 °F)/2 = 

91.5 °F ((51.7 °C + 14.4 °C)/2 = 33.1 °C), 

Btu/(lb · °F) (kJ/(kg · °C)). 

6.4.4 Annual Energy Consumption. The 

annual energy consumption for water heaters 

with rated storage volumes less than 2 

gallons, Eannual, is computed as: 

Where: 

UEF = the uniform energy factor as computed 

in accordance with section 6.4.3 of this 

appendix 

365 = the number of days in a year. 

V = the volume of hot water drawn during 

the applicable draw pattern, gallons 

= 10 for the very-small-usage draw pattern 

= 38 for the low-usage draw pattern 

= 55 for the medium-usage draw pattern 

= 84 for high-usage draw pattern 

r = 8.24 lbm/gallon, the density of water at 

125 °F 

CP = 1.00 Btu/lbm °F, the specific heat of 

water at 91.5 °F 

67 = the nominal temperature difference 

between inlet and outlet water 

6.4.5 Annual Electrical Energy 

Consumption. The annual electrical energy 

consumption in kilowatt–hours for water 

heaters with rated storage volumes less than 

2 gallons, Eannual, e, is computed as: 

Eannual,e = Eannual*(Qe/Q)/3412 

Where: 

Qe = the daily electrical energy consumption 

as defined in section 6.4.2 of this 

appendix, Btu (kJ) 

Eannual = the annual energy consumption as 

determined in accordance with section 

6.4.4 of this appendix, Btu (kJ) 

Q = total energy used by the water heater 

during the 24-hour simulated-use test in 

accordance with section 6.4.2 of this 

appendix, Btu (kJ) 

Qdm = the modified daily water heating 

energy consumption as computed in 

accordance with section 6.4.2 of this 

appendix, Btu (kJ) 

3412 = conversion factor from Btu to kWh 

6.4.6 Annual Fossil Fuel Energy 

Consumption. The annual fossil fuel energy 

consumption for water heaters with rated 

storage volumes less than 2 gallons, Eannual,f, 

is computed as: 

Eannual,f = Eannual¥(Eannual,e × 3412) 

Where: 

Eannual,e = the annual electrical energy 

consumption as defined in section 6.4.5 

of this appendix, kWh. 

Eannual = the annual energy consumption as 

defined in section 6.4.4 of this appendix, 

Btu (kJ) 

3412 = conversion factor from kWh to Btu 


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Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40581 


tkelley on DSK3SPTVN1PROD with RULES2ER11JY14.089</GPH> ER11JY14.090</GPH>

Tom 

tO SCALE 

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IOSCALIE 

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FLOW 

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EXPANSION 

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WATER SUPPLY 

MAIN 

fOO'ANSION 

TANK 
40582 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 


tkelley on DSK3SPTVN1PROD with RULES2ER11JY14.091</GPH>

TO SCALE 

OR 

WATER 

METER 

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X X 

:x: distance from pOrt to edge of unit plus2"' 

Figure 3. 

EXPANSION 

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MAIIII 
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40583 


tkelley on DSK3SPTVN1PROD with RULES2ER11JY14.092</GPH>

TO SCALE 

OR 

WATER 

METER 

Tour 

....,._ ~¢::::=1i'<t:=CJ 

TO SCALE 

OR 

WATER 

METER 

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REGULATOR 

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6" 6" 

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Figure 5. 

EXPANSION 

TANK 

EXPANSION 

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MAIN 
40584 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 


tkelley on DSK3SPTVN1PROD with RULES2ER11JY14.093</GPH>

TO SCALE 

OR 

WATER 

METER 

r.;.,. 

FLOW 

REGULATOR 

x = distance from the center of 

the outlet to the edge of the 

tank, plus two inches 

EXPANSION 

8'' 

Figure 6. 

WATEM SUPPLY 

MAIN 
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40585 

■ 11. Section 430.32 is amended by 

revising paragraph (d) to read as 

follows: 

§ 430.32 Energy and water conservation 

standards and their compliance dates. 

* * * * * 

(d) Water heaters. The energy factor of 

water heaters shall not be less than the 

following for products manufactured on 

or after the indicated dates. 

Product class Storage volume Energy factor as of 

January 20, 2004 Energy factor as of April 16, 2015 

Gas-fired Storage Water 

Heater.

≥20 gallons and ≤100 gallons.0.67¥(0.0019 × Rated 

Storage Volume in gallons).

For tanks with a Rated Storage Volume at or below 55 

gallons: EF = 0.675¥(0.0015 × Rated Storage Volume in gallons). For tanks with a Rated Storage 

Volume above 55 gallons: EF = 0.8012¥(0.00078 × 

Rated Storage Volume in gallons). 


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40586 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

Product class Storage volume Energy factor as of 

January 20, 2004 Energy factor as of April 16, 2015 

Oil-fired Storage Water 

Heater.

≤50 gallons ........................ 0.59¥(0.0019 × Rated 

Storage Volume in gallons).

EF = 0.68¥(0.0019 × Rated Storage Volume in gallons). 

Electric Storage Water Heater.≥20 gallons and ≤120 gallons.0.97¥(0.00132 × Rated 

Storage Volume in gallons).

For tanks with a Rated Storage Volume at or below 55 

gallons: EF = 0.960¥(0.0003 × Rated Storage Volume in gallons). For tanks with a Rated Storage 

Volume above 55 gallons: EF = 2.057¥(0.00113 × 

Rated Storage Volume in gallons). 

Tabletop Water Heater ........ ≥20 gallons and ≤120 gallons.0.93¥(0.00132 × Rated 

Storage Volume in gallons).

EF = 0.93¥(0.00132 × Rated Storage Volume in gallons). 

Instantaneous Gas-fired 

Water Heater.

<2 gallons .......................... 0.62¥(0.0019 × Rated 

Storage Volume in gallons).

EF = 0.82¥(0.0019 × Rated Storage Volume in gallons). 

Instantaneous Electric Water 

Heater.

<2 gallons .......................... 0.93¥(0.00132 × Rated 

Storage Volume in gallons).

EF = 0.93¥(0.00132 × Rated Storage Volume in gallons). 

Note: The Rated Storage Volume equals the water storage capacity of a water heater, in gallons, as certified by the manufacturer. 

Exclusions: The energy conservation 

standards shown in this paragraph do 

not apply to the following types of water 

heaters: gas-fired, oil-fired, and electric 

water heaters at or above 2 gallons 

storage volume and below 20 gallons 

storage volume; gas-fired water heaters 

above 100 gallons storage volume; oilfired water heaters above 50 gallons 

storage volume; electric water heaters 

above 120 gallons storage volume; gasfired instantaneous water heaters at or 

below 50,000 Btu/h. 

* * * * * 

PART 431—ENERGY EFFICIENCY 

PROGRAM FOR CERTAIN 

COMMERCIAL AND INDUSTRIAL 

EQUIPMENT 

■ 12. The authority citation for part 431 

continues to read as follows: 

Authority: 42 U.S.C. 6291–6317. 

■ 13. Section 431.102 is amended by 

adding the definition of ‘‘Residentialduty commercial water heater’’ in 

alphabetical order to read as follows: 

§ 431.102 Definitions concerning 

commercial water heaters, hot water supply 

boilers, and unfired hot water storage 

tanks. 

* * * * * 

Residential-duty commercial water 

heater means any gas-fired, electric, or 

oil storage or instantaneous commercial 

water heater that meets the following 

conditions: 

(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 °F; and 

(3) Does not meet any of the following 

criteria: 

Water heater type Indicator of non-residential 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 >12 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. 

* * * * * 

■ 14. In § 431.106, paragraph (b), Table 

2, is revised to read as follows: 

§ 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) * * * 

TABLE 2 TO § 431.106—TEST PROCEDURES FOR COMMERCIAL WATER HEATERS AND HOT WATER SUPPLY BOILERS

[Other Than Commercial Heat Pump Water Heaters] 

Equipment type Energy efficiency 

descriptor Test procedure 

Test procedure 

required for 

compliance on 

and after 

With these additional stipulations 

Residential-Duty Commercial Water Heater.Uniform Energy Factor.10 CFR Part 430, 

Subpart B, Appendix E.

December 31, 2015*** None. 


tkelley on DSK3SPTVN1PROD with RULES2
Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 40587 

TABLE 2 TO § 431.106—TEST PROCEDURES FOR COMMERCIAL WATER HEATERS AND HOT WATER SUPPLY BOILERS— 

Continued 

[Other Than Commercial Heat Pump Water Heaters] 

Equipment type Energy efficiency 

descriptor Test procedure 

Test procedure 

required for 

compliance on 

and after 

With these additional stipulations 

Gas-fired Storage and 

Instantaneous Water 

Heaters and Hot 

Water Supply 

Boilers*.

Thermal Efficiency ..... Use test set-up, 

equipment, and procedures in subsection labeled 

‘‘Method of Test’’ of 

ANSI Z21.10.3– 

2011**, Exhibit G1.

May 13, 2013 ............ A. For all products, the duration of the standby loss test shall be until whichever of the 

following occurs first after you begin to 

measure the fuel 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, 

equipment, and procedures in subsection labeled 

‘‘Method of Test’’ of 

ANSI Z21.10.3– 

2011**, Exhibit G2.

May 13, 2013 ............ B. For oil and gas products, the standby loss 

in Btu per hour must be calculated as follows: SL (Btu per hour) = S (% per hour) × 

8.25 (Btu/gal-F) × Measured Volume (gal) 

× 70 (degrees F). 

Oil-fired Storage and 

Instantaneous Water 

Heaters and Hot 

Water Supply 

Boilers*.

Thermal Efficiency .....

Standby Loss ............

ANSI Z21.10.3– 

2011**, Exhibit G1.

Use test set-up, 

equipment, and procedures in subsection labeled 

‘‘Method of Test’’ of 

ANSI Z21.10.3– 

2011**, Exhibit G2.

May 13, 2013 ............

May 13, 2013 ............

C. For oil-fired products, apply the 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 § 431.104), and (d) fuel pump 

pressure lies within ±10 percent of manufacturer’s specifications. 

Electric Storage and 

Instantaneous Water 

Heaters.

Standby Loss ............ Use test set-up, 

equipment, and procedures in subsection labeled 

‘‘Method of Test’’ of 

ANSI Z21.10.3– 

2011**, Exhibit G2.

May 13, 2013 ............ D. For electric products, apply the following 

in conducting the standby loss test: (1) Assume that the thermal efficiency (Et) of 

electric 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.’’ 

* As to hot water supply boilers with a capacity of less than 10 gallons, these test methods become mandatory on October 21, 2005. Prior to 

that time, you may use for these products either (1) these test methods if you rate the product for thermal efficiency, or (2) the test methods in 

subpart E if you rate the product for combustion efficiency as a commercial packaged boiler. 

** Incorporated by reference, see § 431.105. 

*** Because the statute permits use of a conversion factor until the later of December 31, 2015 or one year after publication of a conversion 

factor final rule, DOE may amend the mandatory compliance date for use of this amended test procedure, as necessary. 

■ 15. Section 431.107 is added to read 

as follows: 

§ 431.107 Uniform test method for the 

measurement of energy efficiency of 

commercial heat pump water heaters. 


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40588 Federal Register / Vol. 79, No. 133 / Friday, July 11, 2014 / Rules and Regulations 

TABLE 1 TO § 431.107—TEST PROCEDURES FOR COMMERCIAL HEAT PUMP WATER HEATERS

Equipment type Energy efficiency descriptor 

Use test set-up, equipment, and 

procedures in subsection labeled 

‘‘Method of Test’’ of 

Test procedure required for compliance on and after 

Residential-Duty Heat Pump Water 

Heater with Integrated Storage 

Tank.

Uniform Energy Factor ................. 10 CFR Part 430, Subpart B, Appendix E.December 31, 2015*. 

All Other Types .............................. [Reserved] .................................... [Reserved] .................................... [Reserved]. 

* Because the statute permits use of a conversion factor until the later of December 31, 2015 or one year after publication of a conversion factor final rule, DOE may amend the mandatory compliance date for use of this amended test procedure, as necessary. 

[FR Doc. 2014–15656 Filed 7–10–14; 8:45 a.m.] 

BILLING CODE 6450–01–P 


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