Trying to escape through the leak, the particles stick first to the edges of the leak and then to one another. Leaks up to an inch wide can be sealed this way, although cracks up to a quarter-inch wide are the main targets. In 1995 the aerosol sealing project moved out of the laboratory, and tests were done on over a hundred single-family homes all over the country, in climates from New England to the Gulf Coast to the Nevada desert. Lead scientist on this project Learn more about this researcher Often the first challenge was to persuade home-owners they had a problem. It's not like water pipes-people don't wake up at night worrying about them.
Air is invisible.
In fact the energy waste from leaky residential ducts alone is equivalent to the gasoline burned by 13 million cars a year. To seal the ducts in a house, the floor, ceiling and wall registers are covered so that air in the ducts can escape only through the leaks. Sealant is injected for about an hour. Depending on the type of house and the climate, energy savings can reach several hundred dollars a year.