5.7 Direct-Fired Heating Units
This part of the Energy Efficiency Manual shows you how to save energy in residential-type forced air furnaces, wall furnaces, industrial unit heaters, duct heaters, direct-fired air handling units, and other equipment in which fuel is burned within the heating equipment itself.
The energy conservation measures presented here include selecting the most efficient equipment using standard efficiency ratings, including the EER, SEER, and HSPF. The maintenance needed to keep heaters efficient is explained. Other improvements include adding flue dampers to existing heaters, and adjusting thermostats to minimize wasteful cycling of burners.