Can light sealing by CAZ Energy Services. Photo: Hunter Hassig

Many times when homeowners are looking at home improvement solutions for cold spots or high energy bills they think insulation. While insulating your attic and crawl space sub-floor up to code standards is very important for whole home comfort and energy efficiency it is insufficient on its own. This is because in almost every home there are numerous holes in the ceilings that allow air to move freely between your attic space and the conditioned living space of your home. Insulation is a thermal barrier NOT an air barrier. To further illustrate this think of insulation as a sweatshirt. It will keep you warm on a calm day but on a windy one you will need a wind breaker or rain jacket to stay comfortable. Air sealing those holes in your ceiling that lead to the attic creates a consistent, level air barrier that acts as a wind breaker for your home.

Where exactly are these holes? According to The Homeowners’ and Trades Resource Center the three most common areas are wiring penetrations, plumbing penetrations and where your drywall meets up with the framing. Some other trouble areas include soffits, dropped ceilings, chases, vents, exhausts, bath fans, recessed lighting (ie. can lights), and ductwork in your attic. In order to seal small holes like those around bath fans, use silicone caulk or expandable foam. To seal bigger gaps like those found in dropped ceilings and soffits, use rigid foam or drywall (depending on local code) to bring that area to the same level as the rest of the attic and then seal around it with foam or caulk. Sealing these holes will not only save you money on your utility bills but will lead to a more even temperature in the house and many times improve indoor air quality as well.

Some content from: http://blog.sls-construction.com/2011/air-sealing-attic-penetrations