Air leakage occurs when outside air enters and conditioned air leaves your house uncontrollably through cracks and openings. It is unwise to rely on air leakage for ventilation. During cold or windy weather, too much air may enter the house. When it's warmer and less windy, not enough air may enter, which can result in poor indoor air quality. Air leakage also contributes to moisture problems that can affect occupants’ health and the structure’s durability. An added benefit is that sealing cracks and openings reduces drafts and cold spots, improving comfort.

The recommended strategy is to reduce air leakage as much as possible and to provide controlled ventilation as needed. Before air sealing, you should first:

You can then apply air sealing techniques and materials, including caulk and weatherstripping. If you're planning an extensive remodel of your home that will include some construction, review some of the techniques used for air sealing in new home construction and consider a home energy audit to identify all the ways your home wastes energy and money.