In a 2001 federal study, the Lawrence Berkeley National Laboratory (LBNL) measured and calculated the reduction in peak energy demand associated with a cool roof's surface reflectance. LBNL found that, compared to the original black rubber roofing membrane on the Texas retail building studied, a retrofitted vinyl membrane delivered an average decrease of in surface temperature, an 11% decrease in aggregate air conditioning energy consumption, and a corresponding 14% drop in peak hour demand. The average daily summertime temperature of the black roof surface was , but once retrofitted with a white reflective surface, it measured . Without considering any tax benefits or other utility charges, annual energy expenditures were reduced by $7,200 or $0.07/square foot.(This figure is for energy charges as well as peak demand charges).