Features

White Roof Coatings Boost Solar Power

Most of the interest in white roofs comes from the heat reflection of the surface, which reduces energy consumption for cooling.

Charles W. Thurston, Contributing Editor09.14.11

Manufacturers of white roof coatings and emulsions have an emerging niche demand from photovoltaic solar power systems that are designed to absorb the albedo, or reflected light from a flat or low angle roof surface. White sheet materials generally offer reflectivity efficiency in the range of 80 percent, but some liquid formulators are creating products with 90 percent or higher reflectivity efficiency, which can boost the energy production of attuned solar systems by 20 percent to 30 percent over standard flat panels, industry sources say.

While white sheet manufacturers including Carlisle, Firestone, GAF and Johns Manville now control the lion’s share of the white roofing material market. Among materials used for white sheets are vinyl, EPDM, and the most rapidly growing, TPO or thermoplastic polyolefin.

TPO consists of “polymer/filler blends usually consisting of some fraction of PP (polypropylene), PE (polyethylene), BCPP (block copolymer polypropylene), rubber, and a reinforcing filler,” according to Wikipedia. TPO now is used in more than a third of roofing installations, according to one industry estimate.

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