Have you ever set a candle near a window during a bitter Minnesota winter and noticed the flame react to air movement that you cannot feel?
Air leakage can rob you of 25 to 40% of the energy you put into making your home comfortable. A good energy audit company will offer a blower door test as one of a set of tools designed to evaluate your home’s energy usage. The name pretty much says it all: a door with a fan inside is temporarily set up in place of one of your existing doors. All windows and remaining doors are shut as the fan pulls air from the building. This makes the air pressure inside the home lower than outside. Simple physics means air will want to push its way into the structure.
Meters on the blower door are a general indicator of how tight a home is. A home with few air leaks will retain warm air longer in the winter and cool air in the summer. This means you spend less rewarming or recooling air inside your home as it exchanges with the air outside.
In addition to the metered measurement, a good energy audit contractor will use a smoke pencil to detect specific leaks during a home inspection. The smoke is harmless, odor free, and won’t stain. However, it makes invisible air leaks appear as if by magic.
Common Air Leak Locations
Most people think windows leak air but the reality is that the gap between the window frame and the wall is where the air leaks occur. Electrical outlets and wall switches are another area that don’t have as much insulation and allow air to move.
Doors should be properly hung so there are no gaps and weather stripping will help keep drafts to a minimum.
Insulation vs. Air Barriers
Ever wear just a sweater on a windy day? Or a wind breaker on a cold day? There is a difference between keeping yourself warm and protecting yourself from wind. The best solution for your home is a good wool sweater and a windproof jacket; that means a combination of insulation and minimized air leaks will keep your home comfortable.
Once you know where air is leaving your home once you heat or cool it, you can do something to slow that movement if not stop it. Information is power and a simple blower door test in a climate such as Minneapolis can pay for itself many times over in just one heating or cooling season.