Table C403.3.2(4)—Minimum efficiency requirements—Warm air furnaces and unit heaters.
Table 403.3.2(4)
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, e | Test Procedurea |
Warm air furnaces, gas fired | < 225,000 Btu/h | — | 80% AFUE or 80% Etc | DOE 10 C.F.R. Part 430 or ANSI Z21.47 |
| ≥ 225,000 Btu/h | Maximum capacityc | 80% Etf | ANSI Z21.47 |
Warm air furnaces, oil fired | < 225,000 Btu/h | — | 83% AFUE or 80% Etc | DOE 10 C.F.R. Part 430 or UL 727 |
| ≥ 225,000 Btu/h | Maximum capacityb | 81% Etg | UL 727 |
Warm air duct furnaces, gas fired | All capacities | Maximum capacityb | 80% Ec | ANSI Z83.8 |
Warm air unit heaters, gas fired | All capacities | Maximum capacityb | 80% Ec | ANSI Z83.8 |
Warm air unit heaters, oil fired | All capacities | Maximum capacityb | 80% Ec | UL 731 |
For SI: | 1 British thermal unit per hour = 0.2931 W. |
a | Chapter 12 of the referenced standard contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure. |
b | Minimum and maximum ratings as provided for and allowed by the unit's controls. |
c | Combination units not covered by the National Appliance Energy Conservation Act of 1987 (NAECA) (3-phase power or cooling capacity greater than or equal to 65,000 Btu/h [19 kW]) shall comply with either rating. |
| dEt | = | Thermal efficiency. See test procedure for detailed discussion. |
| eEc | = | Combustion efficiency (100% less flue losses). See test procedure for detailed discussion. |
| fEc | = | Combustion efficiency. Units must also include an IID, have jackets 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. |
| gEt | = | Thermal efficiency. Units must also include an 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. |
Reviser's note: The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency.