Over the past few years, scientists at Lawrence Berkeley National Laboratory (LBNL) and Oak Ridge National Laboratory (ORNL) have been studying the energy usage and smog and ozone generation effects of light-colored roofing systems. These research efforts have led to the formation of the Cool Roof Rating Council (CRRC), whose mission is to implement and communicate fair, accurate, and credible radiative energy performance rating systems for roof surfaces.

The potential impact of light-colored roofs is impressive. Light-colored roofs reduce the amount of heat absorbed by a building and reduce the building's cooling load and energy bill. Scientists at these national laboratories have teamed up with Department of Energy (DOE) and Environmental Protection Agency (EPA) experts to document the "urban heat island" problem caused by increasing temperatures in metropolitan areas associated with more buildings, more paved areas, and fewer trees. For instance, since the 1930s, peak summer temperatures in Los Angeles have increased by 8°F. And given that the incidence of smog in Los Angeles rises 3 percent with every degree above 70°F, air quality is directly threatened, not even considering the extra air conditioning requirements and pollution from power plants.
Cool roofs alone could save upwards of $1 billion in annual direct energy costs. Beyond these savings, there might be more dramatic improvements for over 100 United States metropolitan areas that will be designated ozone non-attainment areas under new EPA air quality standards aimed at reducing respiratory illness. Ozone, a leading cause of such illness, forms from smog chemical reactions that accelerate at higher temperatures. Recent computer models predict significant ozone level reductions are possible in areas of greatest population density from use of more reflective roofs. For instance, coating 15 percent of Los Angeles' roofs with white, along with planting shade trees, could translate into temperature reductions of 6°F and smog reductions of 10 percent, producing ozone reductions equivalent to taking 3 to 5 million cars off Los Angeles freeways.

Experts are also looking at cool roofs for added benefits and cost savings associated with extending the life of existing roofs. Over 15 years ago, Dr. Robert Alumbaugh of the Civil Engineering Laboratory, Naval Construction Battalion Center, published papers concluding that higher membrane temperatures of dark roofs and aluminum-coated roofs led to premature failure of traditional built-up roofing systems. Statistics now show that 7 to 10 percent of U.S. landfill space has been taken up by roofing waste over the last 40 years.

CRRC members are urging supporters to become active members of CRRC themselves and to join committees. For more information on the CRRC, visit their website at www.pge.com/pec/progtoc/crrc.html.

For more information on cool roofs, urban heat islands, and related topics, please call Dan Varvais at National Coatings Corporation, 530-647-2822, or search the World Wide Web under "heat island."