Air leaks are one of the biggest saboteurs of your energy bill. They cause your heating and air conditioning units to work overtime. But, you can increase the efficient use of energy by tracking down and eliminating sources of air leaks in your home.

How to Check for Indoor Air Leaks

Close your unit as tightly as possible—shutting doors, windows, flues, anything that vents to the outside. (Leave inside doors open.) Turn on the exhaust fans in the kitchen and bathrooms. This pulls air out of the house or unit and draws outside air in through the leaks. A common way to identify air movements is to hold a lighted incense stick near a suspect area. The smallest movement of air will cause the smoke to move. Another method is to simply hold your damp hand near potential leak sites. Air movement will feel cool.

Where to Check for Air Leaks

Any place one surface joins another (even if it appears closed) is a potential place for air to move in or out of your home—for example, where floor and walls come together, such as around baseboards or carpet edges.

Small spaces don’t allow much air leakage individually, but collectively they can eat up a significant amount of energy. Check all spaces where any type of opening exists such as electrical outlets and switch plates, fireplace dampers, around pipes, attic hatches, mounted air conditioners and mail slots.
Also, be sure to check caulked edges. Don’t assume they’re still air tight. Caulk dries over time and shrinks. Another application might be needed.

Doors and windows are in a category of their own. If they rattle or if you can see daylight around them, they leak. Fortunately, they’re easy to fix with caulking or weather stripping.

Making the Fix

Weather stripping is the simplest and least expensive means to eliminate air leaks around doors. Foam insulation is a variation on caulking that is available as an aerosol spray. It’s well suited for filling large gaps like the holes where pipes or wires enter your home. (Use with caution, however; it expands significantly and can be unsightly if overdone.) For just about everything else, standard caulking is all you need. Once the job is done, test again to make sure you stopped the leak completely.