How does it work?
- Dark-colored roofs and roadways create what is called the "urban heat island effect," meaning a city is significantly warmer than its surrounding rural areas.
- Light colored roofs reduce the heat island effect and improve air quality by reducing emissions.
- Lighter-colored roofing surfaces reflect more of the sun's heat, which helps to improve building efficiency by reducing cooling costs and offsetting carbon emissions.
Roofs and road pavement cover 50 to 65 percent of urban areas. Because they absorb so much heat, dark-colored roofs and roadways create what is called the "urban heat island effect," where a city is significantly warmer than its surrounding rural areas. Light colored roofs or “cool roofs” significantly reduce the heat island effect and improve air quality by reducing emissions. This is because lighter-colored roofing surfaces reflect more of the sun's heat, which helps to improve building efficiency by reducing cooling costs and offsetting carbon emissions. A recent study by researchers at Lawrence Berkeley National Laboratory found that using cool roofs and cool pavements in cities around the world 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.
Most importantly, cool roofs can help homes and businesses save significantly on air conditioning bills. Remember, cool roofs typically cost the same or less than other traditional roofing products, often making it a no-brainer to select cool roof products when it comes time to replace your roof or when building a new home – especially if you live in a warm climate.
As part of the effort to move towards a more sustainable future, Secretary Chu has directed all Energy Department offices to install cool roofs, whenever cost effective over the lifetime of the roof, when constructing new roofs or replacing old ones at Department facilities. With cool roofs, these federal buildings will consume less energy, offset additional carbon emissions, and save taxpayers money.
"Cool roofs are one of the quickest and lowest cost ways we can reduce our global carbon emissions and begUnited in 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."
The Secretary has also issued a letter to the heads of other federal agencies, encouraging them to take similar steps at their facilities. To assist in their efforts, the Energy Department has released a document detailing the Guidelines for Selecting Cool Roofs. This document is a strong starting point for anyone who is considering implementing a cool roof, at both the residential and commercial level. You can also find information about Energy Star cool roofing products on EnergyStar.gov.
If you’ve already installed a cool roof or are in the process of doing so, we’d love to hear about it. Share your experiences and comments with us on Facebook or via e-mail. If you’re just hearing about this approach and want to learn more, check out the video above to hear Secretary Chu break down the benefits of cool roofs.
