Cool Roofs

Department of Energy Secretary Steven Chu announced last week a broad push to cover the federal government’s dark roofs with white paint and other materials that reflect solar thermal energy and help keep buildings cool.

A study by Lawrence Berkeley National Laboratory says these “cool roofs” using solar-reflective surface materials rather than traditional dark roofs cut roof temperatures from 150 °F to less than 100 °F. The change on the roof reduces air-conditioning demands inside and consequently electricity use and carbon dioxide emissions.

In speeches and statements since Chu became DOE secretary, he has stressed the importance of cool roofs, but now he is emphasizing a program to encourage their application for federal buildings.

DOE’s National Nuclear Security Administration, Chu says, has recently installed more than 2 million sq ft of cool roofs and can expect some $500,000 a year in energy cost savings. NNSA estimates it has cut its building heating and cooling costs by 70% on reroofed structures that also include better insulation.

This summer, roof replacements will began at DOE headquarters buildings in Washington, D.C.; Idaho National Laboratory; and Brookhaven National Laboratory, Chu says. He estimates these projects will cover more than 350,000 sq ft of roof space.

Chu also announced that the department will begin a research grant program to encourage development of high-performing, innovative roofing materials.