Cool Roofs

Relying on the centuries-old principle that white objects absorb less heat than dark ones, homeowners like the Waldreps are in the vanguard of a movement embracing “cool roofs” as one of the most affordable weapons against climate change.

Studies show that white roofs reduce air-conditioning costs by 20 percent or more in hot, sunny weather. Lower energy consumption also means fewer of the carbon dioxide emissions that contribute to global warming.

What is more, a white roof can cost as little as 15 percent more than its dark counterpart, depending on the materials used, while slashing electricity bills.

Energy Secretary Steven Chu, a Nobel laureate in physics, has proselytized for cool roofs at home and abroad. “Make it white,” he advised a television audience on Comedy Central’s “Daily Show” last week.

The scientist Mr. Chu calls his hero, Art Rosenfeld, a member of the California Energy Commission who has been campaigning for cool roofs since the 1980s, argues that turning all of the world’s roofs “light” over the next 20 years could save the equivalent of 24 billion metric tons in carbon dioxide emissions.

“That is what the whole world emitted last year,” Mr. Rosenfeld said. “So, in a sense, it’s like turning off the world for a year.”

For more, click here to read all about how "White Roofs Catch On As Energy Cost Cutters" from the New York Times.