Cool roofing is not a new concept.
Travel photos from the Mediterranean and Middle East often show a landscape of homes with white roofs and walls. These are in fact cool roofs, and have been a common architectural element for thousands of years. Although cool roofs are one of the most cost-effective ways to reduce the temperature inside houses during the hot summer, they are not yet widely adopted by western architecture.
Image source: Sondra Jarvis, LBNL
DOE began research on the benefits of cool roofs for energy savings and reducing the summer urban temperature in the 1980s. And now, twenty years after DOE initiated work on cool roofs, these products dominate the commercial roofing marketplace in warm and hot climates, partly because of the state of California. After rolling blackouts during the summer of 2001, California changed its energy code to prescribe cool roofing for most commercial buildings with low-sloped roofs. This has now expanded to cool roofs for steep-sloped roofs as well. These initiatives have helped California’s public utilities reduce peak demand for electricity and help avoid future power outages.