Finding and Fixing Home Air Leaks

You've insulated and caulked, but your house still fills cold and drafty. It's time to search for the remaining home air leaks: Inspect bottom plates, electric outlets and switches, beam pockets and junctions, vanities and sinks.

| January/February 1985

When the temperature dropped and heating costs jumped — two signs of fall — you decided to improve the thermal performance of your home. So to button up your house, you headed down to the hardware store to buy some of those do-it-yourself weatherization kits that you'd seen advertised so widely. You picked up storm windows, rolls of weather stripping and tubes of caulk to seal cracks around doors and windows.

Yet, although you then spent an entire weekend on your weatherization project, winter has shown you that your house is still fairly drafty. There must, you reason, be other places that are letting the north wind blow in.

Finding the Other Home Air Leaks

According to Carl Ellerbrook, an "energy doctor," 80 to 90 percent of the home air leaks (called infiltration) in most houses come from holes that people don't even know about. The average dwelling has 10 or so leakage areas, which may account for as much as 40 percent of the home's total heating and cooling requirements, and those window and door kits you installed only took care of two of them. To really snuggle up for the winter, you've got to find the rest of the gaps in your dwelling's shell.

Ellerbrook's business — through his company, the Sunup Energy Group Ltd. of Old Snowmass, Colo. — is finding and sealing the other leaks. To do so, he performs energy audits using a sophisticated device called a blower door. This huge fan fits into an exterior doorway and pressurizes a building to increase the leakage rate. Then Carl uses a smoke pencil to trace drafts to their sources. With the blower door and smoke pencil, he can pinpoint even small leaks.

"Because every house is different," states Carl, "it's nice to use a blower door and smoke pencil to take the guesswork out of finding leaks." Still, after several years of experience with that equipment, Carl has learned where most of the typical problem areas are in the average home. So although a competent energy audit is the best way to find the thermal leaks in your home, checking out Carl's list of the 10 worst offenders will go a long way toward keeping you cozy when the snow flies.

"You'll find air infiltration anywhere there's penetration through the inside or outside shells of a building," says Ellerbrook. Make a complete walk-through inspection of your house, examining the following areas with particular care. Then seal each leak from the inside of the house. Weatherization materials will last much longer indoors, where they're protected from harsh weather, and moisture problems within the wall will be avoided.

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