Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-11C - State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial › Section 51-11C-403325 - Table C403.3.2(5)-Minimum efficiency requirements-Warm air furnaces and unit heaters

Current through Register Vol. 24-14, July 15, 2024
Table C403.3.2(5)
Warm Air Furnaces and Combination Warm Air
				Furnaces/Air-Conditioning Units, Warm Air Duct Furnaces and Unit
				Heaters-Minimum Efficiency Requirements
Equipment Type
Size Category
						  (Input)
Subcategory or Rating
						  Condition
Minimum
						  Efficiencyd,c
Test
						  Procedurea
Warm-air furnace, gas fired for application outside the
						  U.S.
< 225,000 Btu/h
Maximum capacityc
80% AFUE (nonweatherized)
or
1% AFUE (weatherized) or
80%
Et
b,d
DOE  10 C.F.R. 430  Appendix N or
						  Section 2.39, Thermal Efficiency, ANSI Z21.47
Warm-air furnace, gas fired
< 225,000 Btu/h
Maximum capacityc
80%
Et
b,d before
						  1/1/2023 81%
Et
d after
						  1/1/2023
Section 2.39, Thermal Efficiency, ANSI Z21.47
Warm-air furnace, oil fired
< 225,000 Btu/h
Maximum capacityc
83% AFUE (nonweatherized)
or
78% AFUE (weatherized) or
80%
Et
b,d
DOE  10 C.F.R. 430  Appendix N or
						  Section 42, Combustion UL 727
Warm-air furnace, oil fired
< 225,000 Btu/h
Maximum capacityc
80%
Et
before
						  1/1/2023 82%
Et
d after
						  1/1/2023
Section 42, Combustion UL 727
Electric furnaces for applications outside the
						  U.S.
< 225,000 Btu/h
All
96% AFUE
DOE  10 C.F.R. 430  Appendix N
Warm air duct furnaces, gas fired
All capacities
Maximum capacityc
80%
Ec
e
Section 2.10, Efficiency, ANSI Z83.8
Warm air unit heaters, gas fired
All capacities
Maximum capacityc
80%
Ec
e,f
Section 2.10, Efficiency, ANSI Z83.8
Warm air unit heaters, oil fired
All capacities
Maximum capacityc
80%
Ec
e,f
Section 40, Combustion, UL 731
For SI: 1 British thermal unit per hour = 0.2931 W.
a Chapter 6 contains a complete
				specification of the referenced standards, which include test procedures,
				including the referenced year version of the test procedure.
b Combination units (i.e., furnaces
				contained within the same cabinet as an air conditioner) not covered by DOE
				 10 C.F.R.
				430  (i.e., 3-phase power or with cooling
				capacity greater than or equal to 65,000 Btu/h) may comply with either rating.
				All other units greater than 225,000 Btu/h sold in the U.S. must meet the AFUE
				standards for consumer products and testing using U.S. DOE's AFUE test
				procedure at DOE  10 C.F.R.
				430  Subpart B, Appendix N.
c Compliance of multiple firing rate
				units shall be at the maximum firing rate.
d
Et
= Thermal efficiency. Units must
				also include an interrupted or intermittent ignition device (IID), have jacket
				losses not exceeding 0.75 percent of the input rating, and have either power
				venting or a flue damper. A vent damper is an acceptable alternative to a flue
				damper for those furnaces where combustion air is drawn from the conditioned
				space.
e
Ec
= Combustion efficiency (100% less
				flue losses). See test procedure for detailed discussion.
f Units must also include an
				interrupted or intermittent ignition device (IID) and have either power venting
				or an automatic flue damper.
g This table is a replica of ASHRAE 90.1
				Table 6.8.1-5 Warm-Air Furnaces and Combination Warm-Air
				Furnaces/Air-Conditioning Units, Warm-Air Duct Furnaces, and Unit
				Heaters-Minimum Efficiency Requirements.