According to the Flex Your Power campaign, “approximately $40 billion is spent annually in the United States to cool buildings, one-sixth of all energy consumed annually. Black and dark­-colored roofing materials can dramatically increase a building’s cooling load. Energy-­efficient roofing systems, also called cool roofs, can reduce roof temperature by as much as 100°F during the summer, and thereby re­duce the building’s energy requirements for air conditioning. Cool roofs reflect the sun’s radiant energy before it penetrates the interior of the building.” In fact, keeping the building roof cool helps reduce the urban heat­-island effect, in which cities are markedly (4ºF to 8ºF) warmer than the surrounding countryside, leading to greater use of energy for summer­time air conditioning.

Cool roofs provide a number of potential immediate and long-­term benefits to building owners, including lower utility bills for air conditioning, smaller air conditioning systems, lower roof maintenance costs and longer roof life. Cool roofs help to meet energy-­efficiency goals in building codes and help address a community’s heat-­island effects. Cool roofs are certified by the Cool Roof Rating Council (CRRC). Designers, builders, consultants and owners are showing increasing awareness of how the ra­diative properties of roofs contribute to buildings’ thermal performance. The CRRC recognizes only roofing­-product radiative­-property tests per­formed by independent laboratories.

The LEED rating system gives one credit point to cool roofs that cover at least 75% of a roof surface and have a Solar Reflectance Index (SRI) of at least 78 for a low-sloped roof and 29 for a steep­-sloped roof. The SRI meas­ures the roof surface's ability to reflect solar heat. A standard white roof (80% reflective) has an SRI of 100, while a standard black roof has an SRI of 0. These criteria closely mirror that for an ENERGY STAR-­rated roof. ENERGY STAR­-qualified reflective roof products can reduce peak cooling demand by 10% to 15% and can reduce building energy use by up to 50%.