A roofing system that cuts your electric bill

Researchers at Oak Ridge National Laboratory have come up with a new roof system that could keep your home cool without burning a hole in your wallet. "That's a clay top. The next two over are concrete. The next is metal," says Bill Miller, an ORNL Researcher as he points to more than a dozen types of roofs at the Building's Technology Center.

From a distance, it looks like the type of roof you'd find on any home. Up close, it's cutting edge technology being built at Oak Ridge.

"You want the roof to protect the underlying structure for a long time at an affordable price and that's the real key," Miller said.

The system is made up of several elements including a phase change material that stores the sun's energy without releasing it into a house, then releases it back into the sky at night.

Researchers have added that to radiant barriers, something similar to aluminum foil that reduces the heat flowing from the roof into the attic.

The roof system also includes special ventilation, insulation and reflective paint. The work is part of ORNL's Building Envelopes Program.

"We merge all these technologies together into a real fancy roof, and we are able to knock out 90 percent of the heat flow that goes into the condition space," Miller said.

What does it all mean?

They say the unique roofing system could cut 8 percent off your summer electric bill because your air conditioner doesn't work as hard.

Different combinations of materials add up to different savings, and of course different price tags when putting the system to work.

"When we know how to make it energy efficient, then we can fix it so it would be cost effective," researcher Jan Kosny said. "That's where the contacts with industry are coming from." Several major roofing companies are interested in the work. About 200 sensors wired up to 16 roofs are giving researchers the numbers to prove the system really works. You may one day feel the cooling technology in your home and in your wallet.

Some of the technology is already being used. Researchers hope it will also lead to lowering peak demand on utilities and reducing carbon emissions.