White Roofs Reflect Solar Energy

White Roofs Reflect Solar Energy

Apparently, they have the right idea in the Greek isles.  White roofs reflect solar energy and can dramatically reduce our cooling costs if other nations across the world would also paint their rooftops with reflective paint.  Talk about a super easy, low-cost passive solar energy change you can make to reduce electricity consumption.

Such a low-tech idea may be the hottest thing to hit the solar energy sector recently.  U.S. Department of Energy Secretary Steven Chu observed that global warming may be slowed merely by painting rooftops white.  Instead of investing in expensive renewable energy technology, like solar panels or wind turbines, could we find a viable answer to global climate change in our local hardware store?

Secretary Chu observed:

Making roofs white “changes the reflectivity . . . of the Earth, so the sunlight comes in, it’s reflected back into space.  This is something very simple that we can do immediately.”

A town covered with white roofs

Remember when mom told you to wear light-colored clothing during the summer to keep cool?  Along the same lines, it has been shown that dark-colored roofs absorb more than 80% of solar energy, but white roofs can reflect 75% of it away.  Just think of how much less A/C we’ll need if we all “go white.”

Considering the potential energy savings, California has required most flat-roofed buildings to be white, since 2005.  Walmart has installed them on 75% of its stores in the United States.

While white roofs reflect solar energy, they do not minimize the underlying cause of global climate change – greenhouse gas emissions.  Still, they can address the increased heat from which we suffer during long summer months.  Said Mike Tidwell of the Chesapeake Climate Action Network:

“We may have to figure out a way to artificially cool the planet while the atmosphere is still super-saturated with greenhouse gases, because the planet, it’s a closed system, it’s an absolutely closed system, except for one thing: sunlight.”

Of course, there are several things to keep in mind with white roofs:  First, check your local development code to make sure there are no restrictions on reflective material use.  Second, be sure to maintain the roof so that it does not become damaged or dirty, which will reduce its reflectivity.  Finally, white roofs are generally best suited to flat, rather than sloped, surfaces.  Flat roofs require more maintenance, particularly if it rains often in your region.

Are you sold on the idea of white roofs?  What do you think – great idea, or a bunch of “white-washing”?

Tags: passive solar energy, U.S. Department of Energy Secretary, white roofs reflect solar energy