Solar Impact On Attic
Enables SolarAttic's Energy Technology

Discussion: Figures 1 and 2 below represent the solar radiation intensity hitting a residence located in Kansas City, MO (39 degrees North Lat.), June 21, 1973, at 12 noon. For a 2000 square foot house with a solar radiation intensity at noon of 278 BTUS per square foot per hour, there is a heat gain of 2000 x 278 or 556,000 BTUS PER HOUR. One ton of air conditioning equals 12,000 BTUS per hour. If all the radiant heat from the sun were absorbed by the house, it would take 46 tons of air conditioning to keep the house at 70 degrees F. Why does it not take 46 tons? Part of the heat is reflected. Part is removed by convection. Part of the heat is stopped by insulation at the ceiling line. The reason attic ventilators do such a dramatic job is because there is so much heat left between the roof and the ceiling available to be removed. SOURCE: "The NSP Energy Saving Handbook", James W. Morrison, Harper & Row Publishers, 1979.