Cool colored roofs to save energy and improve air quality

TitleCool colored roofs to save energy and improve air quality
Publication TypeConference Paper
Year of Publication2004
AuthorsHashem Akbari, Paul H Berdahl, Ronnen M Levinson, Stephen Wiel, Andre Desjarlais, William A Miller, Nancy Jenkins, Arthur H Rosenfeld, Chris Scruton
Conference NameACEEE Summer Study on Energy Efficiency in Buildings, August 22-27, 2004
Date Published08/2004
PublisherAmerican Council for an Energy-Efficient Economy
Keywordscool roof, Heat Island

Raising the solar reflectance of a roof from a typical value of 0.1 – 0.2 to an achievable 0.6 can reduce cooling-energy use in buildings by more than 20%. Cool roofs also reduce ambient outside air temperature, thus further decreasing the need for air conditioning and retarding smog formation.We are collaborating with pigment manufacturers to characterize colorants, and with manufacturers of roofing materials to produce cool colored products, including asphalt shingles, tiles, metal roofing, wood shakes, membranes, and coatings. Significant efforts are being devoted to the identification and characterization of pigments suitable for cool-colored coatings, and to the development of engineering methods for applying cool coatings to roofing materials. We are also measuring and documenting the laboratory and in-situ performances of roofing products. Demonstration of energy savings can accelerate the market penetration of cool-colored roofing materials. Early results from this program have yielded colored concrete, clay, and metal roofing products with solar reflectances exceeding 0.4. Obtaining equally high reflectances for roofing shingles is more challenging, but we expect manufacturers to soon have several cost-effective colored shingles with reflectances of at least 0.25.