Over the past few weeks, we’ve noticed a significant uptick in homeowners reaching out to us because they’re noticing significant amounts of frost in their attics. Their biggest questions are why this is happening and what, if anything can be done. Here’s what you need to know about this problematic issue showing up in attics all over the Twin Cities and Western Wisconsin.
Why is Frost Forming? Frost begins to compile when moist air travels to a home’s attic. Once this occurs, it compresses to form frost.
How Does the Air Get There? In one word: humidity. There are a variety of ways this can happen, but one of the easiest is a bath fan that vent to the attic instead of outdoors. Even with this in place, it’s important for bath fans to run for a minimum of thirty minutes after a member of your family takes a bath or shower. This is the very least amount of time it takes for a home’s humidity levels to return to their regular state. Another way a home’s humidity levels can climb dangerously high is through the use of a whole home humidity system. When cooking, run your exhaust fan to cut back on humidity levels. Basements and crawl spaces built sans vapor barrier prove problematic as well.
So What? The real threat of frost begins when it thaws. As it thaws, it saturates the area around it causing damage. Some examples include wet insulation, mold & mildew formation, and water stained ceilings. To tackle this problem, attic air sealing is needed. Areas that should be targeted are attic bypasses. If you’re unfamiliar with this term, it refers to the parts of your home that permit warm air to filter into your attic because they skip contact with your insulation. Examples include recessed lighting, electrical outlets and switch plates, and vents. These bypasses can allow substantial amounts of moist, warm air into the attic.
How a Home Performance Test Can Help: A blower door is a robust fan that is mounted in the frame of one of your front door. The fan is used to pull air out of your home and lower interior air pressure. When this is done, exterior air can flow through any unsealed cracks and openings that exist in the home. A smoke pencil helps identify areas that need to be addressed. The utilization of a FLIR Infrared Imager allows for thermographic scans of your home to be taken. These scans can measure surface temperatures by using infrared video. This test in tandem with a blower door test, identifies air leaks by displaying them as black streaks on the infrared imager. An infrared imager can also help detect roof leaks because wet insulation conducts heat faster than dry insulation.
See How a Home Performance Test is Completed: