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Electronic Code of Federal Regulations

e-CFR data is current as of December 9, 2019

Title 10Chapter IISubchapter DPart 431Subpart G → §431.110


Title 10: Energy
PART 431—ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT
Subpart G—Commercial Water Heaters, Hot Water Supply Boilers and Unfired Hot Water Storage Tanks


§431.110   Energy conservation standards and their effective dates.

(a) Each commercial storage water heater, instantaneous water heater, unfired hot water storage tank and hot water supply boiler (excluding residential-duty commercial water heaters) must meet the applicable energy conservation standard level(s) as specified in the table in this paragraph. 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.

Equipment categorySizeEnergy conservation standarda
Maximum standby lossc (equipment manufactured on and after October 29, 2003)bMinimum thermal efficiency (equipment manufactured on and after October 29, 2003 and
before October 9, 2015)b
(%)
Minimum thermal efficiency (equipment manufactured on and after October 9, 2015)b
(%)
Electric storage water heatersAll0.30 + 27/Vm (%/hr)N/AN/A
Gas-fired storage water heaters≤155,000 Btu/hrQ/800 + 110(Vr) 12 (Btu/hr)8080
   >155,000 Btu/hrQ/800 + 110(Vr) 12 (Btu/hr)8080
Oil-fired storage water heaters≤155,000 Btu/hrQ/800 + 110(Vr) 12 (Btu/hr)7880
   >155,000 Btu/hrQ/800 + 110(Vr) 12 (Btu/hr)7880
Gas-fired instantaneous water heaters and hot water supply boilers<10 gal
≥10 gal
N/A
Q/800 + 110(Vr) 12 (Btu/hr)
80
80
80
80
Oil-fired instantaneous water heaters and hot water supply boilers<10 gal
≥10 gal
N/A
Q/800 + 110(Vr) 12 (Btu/hr)
80
78
80
78
Equipment categorySizeMinimum thermal insulation
Unfired hot water storage tankAllR-12.5

aVm is the measured storage volume (in gallons), and Vr is the rated volume (in gallons). Q is the nameplate input rate in Btu/hr.

bFor 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.”

cWater heaters and hot water supply boilers having more than 140 gallons of storage capacity need not meet the standby loss requirement if: (1) The tank surface area is thermally insulated to R-12.5 or more; (2) a standing pilot light is not used; and (3) for gas or oil-fired storage water heaters, they have a fire damper or fan-assisted combustion.

(b) Each residential-duty commercial water heater must meet the applicable energy conservation standard level(s) as follows:

Product classSpecificationsaDraw patternUniform energy factorb
Gas-fired Storage>75 kBtu/hr and ≤105 kBtu/hr and ≤120 galVery Small
Low
0.2674 − (0.0009 × Vr)
0.5362 − (0.0012 × Vr)
   Medium0.6002 − (0.0011 × Vr)
   High0.6597 − (0.0009 × Vr)
Oil-fired Storage>105 kBtu/hr and ≤140 kBtu/hr and ≤120 galVery Small
Low
0.2932 − (0.0015 × Vr)
0.5596 − (0.0018 × Vr)
   Medium0.6194 − (0.0016 × Vr)
   High0.6740 − (0.0013 × Vr)
Electric Instantaneous>12 kW and ≤58.6 kW and ≤2 galVery Small0.80
   Low0.80
   Medium0.80
   High0.80

aAdditionally, to be classified as a residential-duty commercial water heater, a commercial water heater must meet the following conditions: (1) if the water heater requires electricity, it must use a single-phase external power supply; and (2) the water heater must not be designed to heat water to temperatures greater than 180 °F.

bVr is the rated storage volume (in gallons), as determined pursuant to 10 CFR 429.44.

[81 FR 96238, Dec. 29, 2016]

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