Equipment,% of buildings using it,% of floorspace in buildings using it,% of heated floor area it serves,Floor area served (million sq ft),Buildings where it is the main system (thousand),"Main system, % of heated buildings"
Packaged unit,37.0,49.8,38.9,"30,130","1,908",38.9
Boiler,11.9,29.7,24.6,"19,049",514,10.5
Furnace,27.4,17.9,11.6,"8,965","1,366",27.9
Individual space heater,21.1,21.8,7.1,"5,474",585,11.9
District steam or hot water,1.4,6.7,7.0,"5,450",78,1.6
Heat pump,11.4,15.6,7.0,"5,388",388,7.9
"Other (fireplaces, duct reheat, solar, other)",n/a,n/a,3.9,"2,998",62,1.3