=+1-22. If cold outside air at 20 F is leaking into a 20-ft by 30-ft by 10-ft room where the heating sys-

tem is trying to maintain a comfortable temperature of 72 F, then the same amount of air might be assumed to be leaking out of the room. If one were to estimate that this rate of leakage amounted to about 0.4 air changes per hour (see Problem 1-19), what load would this leakage place on the heating system, in Btu/hr? Assume that the air lost is at the assumed room com-

fort temperature and is replaced by the cold outside air. Assume an air density of 13.5 cubic feet per pound mass and a c ,, = 0.24 Btu/(Ibm-F).