The Problem: Lawrence Berkeley National Laboratory houses several thousand researchers, many of them cloistered in labs investigating scientific mysteries like the role of dark energy in the cosmos and the genetic code for human viruses. But one group became enthralled by, of all things, air-conditioning ducts. And oddly enough, they made an important discovery: In most households, about 20 percent of the heated or cooled air traveling through air ducts leaks through holes and cracks.

The Solution: The Lawrence Berkeley researchers, led by Mark Modera, devised a new aerosol sealant technique using a vinyl polymer, which reduces the leaks by 90 percent. A technician simply covers up a home's air vents and then blows a "fog" of the sealant through the ducts. The fog pushes into holes and cracks, plugging them with the polymer particles. Unlike traditional sealing methods -- think duct tape -- the aerosol method allows workers to catch leaks that would normally be inaccessible. Modera and his colleagues brought the invention to market through a company called Aeroseal.

California alone loses $1 billion to $2 billion a year in energy leaks from faulty heating and cooling ducts. Beginning in 2005, new state regulations will require most homeowners who replace their central air conditioner to seal these ducts. Other states, including New York and Texas, have also passed legislation or altered building codes to encourage the practice. "The biggest challenge is consumer awareness," says Modera. But he's working on solving that problem, too: Aeroseal now has 70 franchises nationwide.

Copyright 2004 by the Natural Resources Defense Council