Dept. of Energy to install energy-saving white roofs on department facilities.

Despite ridicule from conservative pundits like Rush Limbaugh for suggesting that painting roofs white or installing other energy efficient "cool roof" materials to reflect sun and reduce cooling costs was silly, Energy Secretary Steven Chu today announced the first initiative to start turning federal roofs white.

Secretary Chu today directed all Department of Energy (DOE) offices to install cool roofs, whenever cost effective over the lifetime of the roof, when constructing new roofs or replacing old ones at DOE facilities.

"Cool roofs are one of the quickest and lowest cost ways we can reduce our global carbon emissions and begin the hard work of slowing climate change," said Secretary Chu.

"By demonstrating the benefits of cool roofs on our facilities, the federal government can lead the nation toward more sustainable building practices, while reducing the federal carbon footprint and saving money for taxpayers." [Read Secretary Chu's memorandum on Cool Roofs (pdf)]

In addition to creating energy savings for individual buildings -- cool roofs can easily slash a building's energy consumption by 20 percent -- cool roofs also reduce the "urban heat island effect," the phenomena that occurs when rooftops and pavements in a city make it substantially warmer than the surrounding rural areas. Roofs and road pavement cover 50 to 65 percent of urban areas.

Cool roofs as climate change mitigation

A new study on the climatic impacts of cool roofs by researchers at Lawrence Berkeley National Laboratory confirms that using cool roofs and cool pavements in cities can help reduce the demand for air conditioning, cool entire cities, and potentially cancel the heating effect of up to two years of worldwide carbon dioxide emissions.

“If all eligible urban flat roofs in the tropics and temperate regions were gradually converted to white (and sloped roofs to cool colors), they would offset the heating effect of the emission of roughly 24 Gt of CO2, but one-time only,” says Berkeley physicist Art Rosenfeld, one of the paper's authors.

“However, if we assume that roofs have a service life of 20 years, we can think of an equivalent annual rate of 1.2 Gt per year. That offsets the emissions of roughly 300 million cars (about the cars in the world) for 20 years!”

Energy Secretary Chu also issued a letter to the heads of other federal agencies encouraging them to take similar steps as DOE in implementing cool roofs going forward.

Watch Chu explain the benefits of cool roofs:

Photo credit: NNSANews via flickr