Roof solar reflectance and cooling energy use: field research results from Florida

Traditionally, architects have recognized that reflective building colors can reduce building thermal loads. Experiments in Florida have examined the impact of reflective roof coatings on air conditioning energy use in a series of tests on occupied homes. The experiments were conducted on nine residential buildings from 1991 to 1994 using a before and after test protocol where the roofs were whitened at midsummer. Measured air conditioner electrical savings in the buildings during similar pre and post-weather periods averaged 19%, ranging from a low of 2% to a high of 43%. Utility peak coincident peak savings averaged 22% with a similar range of values. Cooling energy reductions appear to depend also on initial ceiling insulation level and roof solar reflectance, air duct system location and air conditioner sizing.