Sacramento researchers coated a retail store’s dark roof white in 2002. Its peak roof temperature fell by up to 42°C and air-conditioning energy use dropped 52%

In 2002, Sacramento researchers coated a retail store’s dark roof with a reflective cool-roof coating. The roof’s peak surface temperature fell by up to 42°C, while the building’s air-conditioning energy use dropped by about 52%, highlighting the potential of reflective roofs to reduce cooling demand. But the researchers found that the building itself also played an important role.