Commercial Water Heating Equipment
The Department of Energy (DOE) has regulated the energy efficiency level of commercial water heating equipment since 1992. Commercial water heating equipment includes gas-fired, electric, and oil-fired commercial storage water heaters, gas-fired and oil-fired instantaneous water heaters and hot water supply boilers, and unfired hot water storage tanks. Commercial water heating equipment is used to provide hot water on demand and is industrial equipment. Storage water heaters heat and store water in a thermostatically controlled tank. Instantaneous water heaters heat water on demand. Hot water supply boilers heat potable water for uses other than space heating. Unfired hot water storage tanks are tanks that store water that is heated externally.
The standard implemented in 1994 will save approximately .07 quads of energy and result in approximately $730 million in energy bill savings for products shipped from 1994-2013. The standard will avoid about 4 million metric tons of carbon dioxide emissions, equivalent to the annual greenhouse gas emissions of about 784,000 automobiles.
Recent Updates | Standards | Test Procedures | Waiver, Exception, and Exemption Information | Statutory Authority | Historical Information | Contact Information
DOE published notice of proposed rulemaking and announcement of public meeting regarding energy conservation standards for certain commercial and industrial equipment including commercial water heaters. 80 FR 1172 (January 8, 2015). For more information, please see the rulemaking page.
DOE published a Federal Register request for information regarding energy conservation standards for commercial water heating equipment. 79 FR 62899 (October 21, 2014).
DOE published a Federal Register final rule regarding test procedures for residential water heaters and certain commercial water heaters 79 FR 40541 (July 11, 2014). For more information, please see the rulemaking webpage.
Standards for Commercial Water Heating Equipment
The following content summarizes the energy conservation standards for commercial water heating equipment. The text is not an official reproduction of the Code of Federal Regulations and should not be used for legal research or citation.
Commercial water heating equipment manufactured and distributed in commerce, as defined by 42 U.S.C. 6291(16), on and after October 29, 2003 must meet the energy conservation standards specified in the Code of Federal Regulations, 10 CFR 431.110. This information is also available in the Electronic Code of Federal Regulations.
Each commercial storage water heater, instantaneous water heater, unfired hot water storage tank and hot water supply boiler must meet the applicable energy conservation standard level(s) as follows. (Note: Any packaged boiler that provides service water, that meets the definition of "commercial packaged boiler" in subpart E of this part, but does not meet the definition of "hot water supply boiler" in subpart G, must meet the requirements that apply to it under subpart E.)
Table 1. Energy Conservation Standards for Commercial Water Heating Equipment
||Minimum Thermal Efficiency
||Maximum Standby Lossa,b
|Electric storage water heaters
||0.30 + 27/Vm (%/hr)
|Gas-fired storage water heaters
||Q/800 + 110(Vr)1/2 (Btu/hr)
|Oil-fired storage water heaters
||Q/800 + 110(Vr)1/2 (Btu/hr)
|Gas-fired instantaneous water heaters and hot water supply boilersc
||> 10 gal
Q/800 + 110(Vr)1/2 (Btu/hr)
|Oil-fired instantaneous water heaters and hot water supply boilersc
||< 10 gal
Q/800 + 110(Vr)1/2 (Btu/hr)
||Minimum Thermal Insulation
|Unfired hot water storage tank
a Vm is the measured storage volume, Vr is the rated volume, and Q is the nameplate input rate in Btu/hr.
b Water Heaters and hot water supply boilers having more than 140 gallons of storage capacity need not meet the standby loss requirement if (1) the tank surface area is thermally insulated to R-12.5 or more, (2) a standing pilot light is not used and (3) for gas- and oil-fired storage water heaters, they have a fire damper or a fan assisted combustion.
c For hot water supply boilers with a capacity of less than 10 gallons: (1) the standards are mandatory for products manufactured on and after October 21, 2005, and (2) products manufactured prior to that date, and on or after October 23, 2003, must meet either the standards listed in this table or the applicable standards in subpart E of this part for a "commercial packaged boiler."
For further guidance or to submit questions related to the implementation of this standard, visit the Guidance and Frequently Asked Questions page.
Current Test Procedure
To determine compliance with DOE standards, manufacturers must follow the test procedures specified at 10 CFR 431.106 for commercial water heating equipment. These are also in the Electronic Code of Federal Regulations.
Direct Final Rule: Test Procedures and Standards, Federal Register, FR 69 61974 (Oct. 21, 2004)
Amended Test Procedure:
DOE published amended test procedures on May 16, 2012. The test procedures are required on or after May 13, 2013.
For further guidance or to submit questions related to the implementation of this test procedure, visit the Guidance and Frequently Asked Questions page.
Test procedure waivers have not been issued for commercial water heating equipment.
For information about obtaining test procedure waivers, see 10 CFR 431 subpart V.
DOE's Office of Hearings and Appeals has not authorized exception relief for commercial water heating equipment.
For information about obtaining exception relief, see 10 CFR part 1003.
State Exemptions to Federal Pre-emption
DOE has not exempted any state from this energy conservation standard. States may petition DOE to exempt a state regulation from preemption by the Federal energy conservation standard. States may also petition DOE to withdraw such exemptions. For details, see 10 CFR 431 subpart V or 10 CFR 431 subpart W.
The energy conservation standards for commercial water heating equipment are mandated by Part A–1, the "Certain Industrial Equipment" of Title III of the Energy Policy and Conservation Act (EPCA), as amended. (42 U.S.C. 6311–6317). This equipment is treated as covered equipment under Part A-1. 42 U.S.C. 6311(1)(K)
The standards for all equipment classes except for hot water supply boilers were originally set in EPCA. On January 12, 2001, DOE issued a final rule adopting the efficiency levels for commercial water heating equipment in ASHRAE Standard 90.1-1999 for all equipment classes except for electric water heaters. DOE also adopted the efficiency levels contained in the Addendum to ASHRAE Standard 90.1-1989 for hot water supply boilers, which were identical to the efficiency levels as instantaneous water heaters. These same efficiency levels are in place today. 66 FR 3336. On October 21, 2004, DOE published a direct final rule for commercial water heaters and hot water supply boilers that prescribed relevant definitions and recodified existing energy conservation standards so they would be located contiguous with the test procedures. 69 FR 61974.
Helpful Links and Contact Information
For tips and guidance for making your home, workplace, or vehicle more energy efficient visit EnergySavers.gov.
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