White Roofs Bring Cool Savings

No matter where you live, you can save energy and money by switching to a white, or “cool,” roof, for about the same cost as a conventional roof.

| February/March 2010

White roofs, aka cool roofs, are a “hot” topic these days as a means to help stem global warming. Most of us know better than to wear black on a hot day, but when it comes to the roofs on our houses, temperature often takes a back seat to aesthetics . Dark roofs mean higher air conditioning bills, and higher carbon dioxide emissions as a result. The good news is you can save money and help protect the planet by lightening the color (and therefore the temperature) of your roof, or by switching to a white roof the next time your house needs a new hat.

The Benefits of a White Roof

Switching to a white roof can actually reduce energy use by about 20 percent in hot, sunny weather, according to the Lawrence Berkeley National Laboratory Heat Island Group in Berkeley, Calif. Hashem Akbari, the Heat Island Group’s lead scientist and a professor of Building, Civil and Environmental Engineering at Concordia University in Montreal, says that transitioning to reflective roofing and pavements in the world’s urban areas would offset the equivalent of emissions from the planet’s 600 million cars for the next 18 years. A 1,000-square-foot cool roof saves air conditioning use that otherwise would emit about half a ton of carbon dioxide per year. (The average total square footage of a home in the United States is more than 2,000.)

In urban areas, white roofs also help lower smog levels by lowering local temperatures, which tend to be higher due to the large proportion of paved surfaces.

Critics have suggested white roofs do more harm than good in colder climates. But research shows that the heating benefits of a dark roof in the winter are negligible because days are shorter, skies are cloudier, the angle of the sun is low, and sometimes roofs are covered in snow. “The amount of heat savings you may lose in the winter would be, at the maximum, 30 percent of the summertime savings,” Akbari says. “If you need cooling in the summer and heating in the winter, no matter where you are, a white roof will most likely save you money.”

Cool New Roof Options

“Cool” is the buzzword that encompasses a range of roofing materials that can reduce carbon footprints. And cool roofs come in a variety of light colors.

The best time to install a cool roof is when a new roof is needed or major roof maintenance is in order. According to researchers, there’s little difference between the cost of roof colors.

3/28/2014 12:59:03 AM

White roofs reflect a tremendous amount of the sun's rays. However, insulating underlayment does the bulk of the work as far as keeping temperatures down is concerned. There is an effect known as a "heat island" which is the cumulative effect of radiant heat and energy keeping surrounding temperatures hotter longer in the day. This is seen commonly in cities like College Station due to the expansive swaths of concrete sidewalks and buildings. If areas and municipalities would adopt white roofs, http://www.schulteroofing.com/college-station-roofer could really help the greenhouse effect.

3/16/2012 7:21:31 PM

I've been living in NC for over 40 years. I've never understood WHY 95% of buildings have dark roof covering. In a climate where temps can be in the high 70's to mid 80's 8 months of the year, and into the low hundreds the rest of the time, a WHITE roof would seem to be a no brainer.

4/16/2011 12:35:05 PM

For emelle_3: Get some solar shades that prevent 90% of the solar gain and are still translucent. Before you purchase any, find out what they're made of. You also don't want a lot of pvc inside the house.

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