Narrator: This is Science Today. If your household energy bills seem to be running high you may have leaky air ducts. Mark Modera, a staff scientist at the Lawrence Berkeley National Laboratory says most homes in the U.S. have leaky air ducts, causing about a 20 percent loss of energy. But there are other reasons - besides wasted energy - to be concerned about these leaks.

Modera: It also winds up sucking in air from places that you don't necessarily want it from. In some places like from a crawl space, where you can have radon be drawn into the house. Other places would be from the garage, where you're parking your car, warming up your car, that's also not terribly desirable.

Narrator: Modera developed an efficient air sealant system, which can fix leaks from inside the ducts. Using a computer as a tracking device, this system can also quickly diagnose leakage problems.

Modera: The computer just makes it more accessible. In other words, to go through a house and within an hour to an hour and a half, be able to decide OK, these are things that should be done in this particular house.

Narrator: For Science Today, I'm Larissa Branin.