Warm air furnaces, gas fired

< 225,000 Btu/h

—

78% 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

—

78% 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.

Chapter 6 of the referenced standard contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure.

Minimum and maximum ratings as provided for and allowed by the unit's controls.

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.

 

=

Thermal efficiency. See test procedure for detailed discussion.

 

=

Combustion efficiency (100% less flue losses). See test procedure for detailed discussion.

 

=

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.

 

=

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.