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.