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

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URL: https://www.frixlaw.com/law-library/documents/fr%3A2014-15656

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** July 11, 2014
- **Citation:** 79 FR 40542

## Text

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-TP-0042.
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 B
1

of the Energy Policy and Conservation Act of 1975 (“EPCA” or “the Act”), Public Law 94-163 (42 U.S.C. 6291-6309, as codified) sets forth a variety of provisions designed to improve energy efficiency and established the Energy Conservation Program for Consumer Products Other Than Automobiles.
2

These include 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))

1
For editorial reasons, upon codification in the U.S. Code, Part B was redesignated as Part A.

2
All references to EPCA in this document refer to the statute as amended through the American Energy Manufacturing Technical Corrections Act (AEMTCA), Public Law 112-210 (Dec. 18, 2012).

3
For editorial reasons, upon codification in the U.S. Code, Part C was redesignated Part A-1.

Under EPCA, energy conservation programs generally consist of four parts: (1) Testing; (2) labeling; (3) establishing Federal energy conservation standards; and (4) certification and enforcement procedures. The testing requirements

consist of test procedures that manufacturers of covered products and equipment must use as the basis for certifying to DOE that their products and equipment comply with the applicable energy conservation standards adopted 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 Air-Conditioning 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.

4
On May 16, 2012, DOE published a final rule in the
Federal Register
amending the test procedures for commercial water heaters. 77 FR 28928.

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.

5
For more information, please visit DOE's Web site at:
http://www1.eere.energy.gov/buildings/appliance_standards/residential/waterheaters.html.

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

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).

6
ACEEE 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).

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

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) Gas-fired 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).

7
As 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.

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 “residential-duty” commercial water heater classification.
9

8
All 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.

9
As 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).

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

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 “residential-duty” 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.

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 oil-fired water heaters with storage volumes less than or equal to 50 gallons (190 L). 10 CFR part 430, subpart B, appendix E, sections 1.12.1, 1.12.2, and 1.12.4.

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 storage-type 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

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 water-heating 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 oil-fired 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 “residential-duty 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, gas-fired 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.

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 storage-type 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 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.

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

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 “E
f
” 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 simulated-use 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 large-capacity 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

field data available for a medium-usage situation.

10
Lutz, 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).

DOE considered adding a fifth draw pattern as recommended by AET, but a review of data from testing of low-volume 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 first-hour rating to assign a draw pattern for use during the simulated-use test. DOE examined using a combination of first-hour 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 first-hour 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.

11
Test 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
.

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-small-usage.”

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

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)

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.

12
Healy 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).

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

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.

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:

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).

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 one-fourth 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.

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 user-accessible 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

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 pre-conditioning 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 soak-in 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

uncertainty to the critical measurement of average tank temperature at the start of the test. Consequently, DOE adopts a requirement that the 24-hour simulated-use test be preceded by at least a one-hour 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

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 b

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2014-15656. Public record. Not legal advice.