In the summer of 2002, researchers in Sacramento tested a deceptively simple way to reduce the amount of heat entering a commercial building by changing the surface of its roof. The building was a retail flooring showroom with a dark roof that absorbed large amounts of sunlight. After researchers applied a reflective cool roof coating, the difference was dramatic.
The roof surface became as much as 42°C cooler, while the building's air-conditioning energy use fell by roughly 52% during the monitoring period. The experiment offered a striking real-world demonstration of how much a roof can influence a building's energy consumption.
