Hot cash on a white roof

From the California Energy Commission’s Fifth Annual Climate Change Research Conference:

“White roofs can cut a building’s energy use by 20 percent and save consumers money,” says California Energy Commissioner Art Rosenfeld. “The potential energy savings in the U.S. is in excess of $1 billion annually. Additionally, by conserving electricity we are emitting less CO2 from power plants,” Rosenfeld added.

If you break it down annually, it’s about $250 per 1,000 square feet. Since 2005, California commercial buildings have been required to have white roofs. Starting in 2009, new residential roofs and retrofit constructions will be required to have “cool-colored” roofs, which reflect a higher fraction of the sun’s rays than current roofing materials of the same color. Most states offer some energy incentive package for white roof adopters, according to a company trying to sell you a white roof.

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2 Responses to “Hot cash on a white roof”

  1. Jay-Jay Says:

    THIS is the kind of step that CA should be taking to improve energy efficiency. It’s increasing the albedo (reflectivity) of the earth, so something that would’ve been a heat sink is no longer adding to the “heat island” effect of cities. It is a cheap way to reduce heat absorption.

  2. JGM Says:

    Well, I can see that it would be useful in southern states, especially in the south-west. What about those of us in the north. White roofs would lower cooling costs in the summer but would likely raise heating costs in the winter, as you would be losing the “free” solar heating of the building at that point. What would be ideal would be a temperature sensitive roofing material that would transition from a dark color to a light color as the temperature increased. Helping to retain heat in winter but reflect it in the summer.

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