What is energy-efficient?

A study shows factors other than color affect roof system energy efficiency

Recently, government-driven energy-conservation programs have affected the roofing industry. For example, the U.S. Department of Energy successfully has promoted the use of light-colored roof membranes through its ENERGY STARĀ® program. And studies conducted by Lawrence Berkeley National Laboratories, Berkeley, Calif., have focused on heat islands and their potential effects on air pollution. The studies indicate that factors contributing to high temperatures in urban environments include a lack of vegetation, nonreflective roofing materials and dark-colored pavements. Of the three causal factors, lack of vegetation is thought to contribute to 56 percent of the temperature rise with roofing and pavement contributing to the remainder.

Although these environmental initiatives have received a great deal of emphasis in urban areas within the southern United States, the sweeping application of new energy standards has forced many roofing contractors to abandon preferred roofing products.

The Chicago factor

Nowhere have energy standards gained more attention than in Chicago where a new Chicago Energy Code was approved in June. The standard includes the requirement that newly installed roof systems maintain an albedo of 0.65 (a solar reflectance of 65 percent), which eliminates the use or substantially increases the cost of predominant roof systems in the Chicago area. The Chicago Energy Code currently is under review to finalize acceptable levels of reflectivity. The code body is considering an approach that gradually would phase in the reflectivity standard over time.