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, concrete and clay tiles, metal roofing, wood shakes, and coatings. In this collaboration, we have identified. and characterized pigments suitable for cool-colored coatings, and developed

engineering methods for applying cool coatings to roofing materials. Weare 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 ITomthis effort 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 some manufacturers have already developed several cost-effective colored shingles with solar reflectances of at least 0.25.