Energy Efficient Home Heating and Cooling

Taking the time to properly seal and insulate your home is one of the fastest returns on your investment of time and money. Most experts agree that caulking and weather stripping any gaps will pay for itself within one year in energy savings. Caulking and weather stripping will also alleviate drafts and help your home feel warmer when it's cold outside. However, these two weatherization techniques can't replace the need for proper insulation throughout your home.

How Does Energy Escape Your Home?

Warmed or air-conditioned air mixes with outside air through gaps in your home's thermal envelope-exterior walls, windows, doors,the roof, and floors. Such air leaks can waste large amounts of energy.

Accessing air quality

Because caulk and weatherstripping limit indoor‑outdoor air circulation, you should assess your indoor air quality before you apply them. Some homes contain dust, mold, carbon dioxide, and other indoor air contaminants. Sealing air leaks in these homes, without proper ventilation, can also seal in their indoor air pollutants. There­fore, any plan to tighten the thermal enve­lope of a home should be accompanied by a look at your home's ventilation needs.

This fact sheet does not cover indoor air quality assessment and ventilation. See "Resources" at the end of this fact sheet for whom to contact for more information.

Detecting air leaks

You may already know where some air leakage occurs in your home, such as an under-the-door draft that makes you want to put on socks. But you'll probably need to search to find the less obvious gaps.
Look between foundation and walls, and between the chimney and siding. Also inspect around the fol­lowing areas for any cracks and gaps that could cause air leaks.

Common Locations For Air Leaks

* Door and window frames
* Mail chutes
* Electrical and gas service entrances
* Cable TV and phone lines
* Outdoor water faucets
* Where dryer vents pass through walls
* Bricks, siding, stucco, and foundation
* Air conditioners
* Vents and fans.

Techniques for Identifying Air Leaks

Depressurize your home to help detect leaks. On a cool, very windy day, turn off the furnace. Shut all windows and doors. Turn on all fans that blow air outside, such as bathroom fans or stove vents. Then light an incense stick and pass it around the edges of common leak sites. Wherever the smoke is sucked out of or blown into the room, there's a draft. Or just turn on all your exhaust fans (don't need to turn off the furnace) and try one of these methods:

* At night, shine a flashlight over all potential gaps while a partner observes the house from outside. Large cracks will show up as rays of light. Not a good way to detect small cracks.
* Shut a door or window on a piece of paper. If you can pull it out without tearing, you're losing energy.

For a more thorough and accurate measurement of air leakage, you can hire a technician to conduct a blower door test in your home. Blower doors are variable-speed fans with a frame and shroud that allows them to fit inside a variety of door frames. Pressure gauges determine airflow through the fan, as well as fan-induced pressure. The leakier a house, the more airflow required to induce a pressure difference. When used as a diagnostic tool, a blower door can also reveal the location of many leaks.