Save energy. Install a cool roof.
Many communities are taking action to reduce urban heat islands, and cool roofs are among the strategies they are using. Cool roofs can lower cooling energy use, peak electricity demand, air pollution and greenhouse gas emissions, and solid-waste generation due to less frequent re-roofing.
Building owners and roofing contractors have used cool roofing products for more than 20 years. They may be installed on the flat or gently sloping roofs typically found on commercial, industrial and office buildings, and they may also be used on the steep-sloped roofs used in many residences and retail buildings.
Through the Energy Star program, the EPA and the U.S. Department of Energy (DOE) help consumers and other purchasers identify the most energy-efficient roofing products. Roofing materials with the Energy Star label have met the minimum solar reflectance and reliability criteria. A high solar reflectance is the most important characteristic of a cool roof, because as it reflects sunlight away from a building, it also reduces roof temperatures. A high thermal emittance also plays a role, particularly in climates that are warm and sunny. Together these properties help roofs to absorb less heat and remain as much as 50 to 60 degrees cooler than conventional roofing materials during peak summer weather.
The cost premium for cool roofs versus conventional roofing materials ranges from zero to 5 or 10 cents per square foot for most products. In the case of a built-up roof with a cool coating used in place of smooth asphalt or an aluminum coating, the differential may be 10 to 20 cents per square foot. However, a California study found that cool roofs provide an average yearly net savings of almost 50 cents per square foot. This number takes into account the price premium for cool roofing products, increased heating costs in the winter, summertime energy savings, savings from downsizing cooling equipment, and reduced labor and material costs over time due to the longer life of cool roofs compared with conventional roofs.
The EPA maintains an Urban Heat Island Community Actions Database, which provides information on more than 75 local and statewide initiatives to reduce heat islands and achieve related benefits. Click to find out which communities have cool roof initiatives under way.
- Bisphenol A (BPA)
- Hexavalent Chromium
- Methylene chloride (dichloromethane)
- Perchloroethylene (Tetrachloroethylene, PERC, PCE)
- Propoxur (Flea and Tick Pesticide)
- Sulfur Dioxide
- TDCP/TCEP (Chlorinated Flame Retardants)
- Tetrachlorvinphos (Flea and Tick Pesticide)
- Trichloroethylene (TCE)
- Triclosan and Triclocarban (Antibacterials)