Air sealing is an extremely important component of energy efficiency. The process involves identifying openings in the air barrier of the home, and then properly sealing them. When we discuss an air barrier, we are referring to the “building envelope” - a boundary between conditioned space and unconditioned space. The tighter the envelope, the less air is leaking in and out of your home. Generally, the air barriers in a home are the exterior walls, the attic floor, and the ceiling of the basement or crawl space. These are the locations which contain unintended pathways for air infiltration and exfiltration. Some examples are plumbing and electrical penetrations, unsealed recessed/canned lights, open chase ways, open bottom and top plates, and band (or "rim") joists.
How Does Air Sealing Help Energy Efficiency?
Air sealing is like a windbreaker for your house. Have you ever been outside on a cool, windy day and put on a sweater to stay warm? You may have felt warmer, but you will likely still feel the wind blowing through. The best option would be to pair a sweater with a windbreaker for maximum warmth and comfort. You can think of your home in the same way. The insulation is like your sweater, and a properly sealed envelope is like your windbreaker.
When your HVAC system turns on, it pulls air into the central return from wherever it can along the path of least resistance. It then heats or cools and dehumidifies the air before it forces it out to each room via the registers. Oftentimes the systems will pull air from your attic or basement. When these spaces have openings in the envelope and outdoor air is leaking in, then your HVAC system is working overtime to cool or heat the air. Your system works more efficiently when it pulls air from spaces with a tighter barrier. Proper air sealing is so important and will help keep your home more comfortable and your power bills lower.