Windows are usually the first thing that come to mind when most people think about leaky or drafty houses, but attics and basements are often responsible for far more air leakage into and out of homes.

In the basement, unsealed rim joists (where the house's frame sits on the foundation), holes for electrical wires and plumbing pipes, and open chases allow cold air to travel up through walls. In the attic, unsealed top plates (wooden boards that form the top of interior walls), open chases, and holes for electrical wires, electical boxes plumbing pipes allow warm air to escape through gable vents and ridge vents.

Air sealing attics and basements is one of the most effective ways to retain conditioned air and prevent outside air from getting in. Reducing the amount of air that leaks in and out of your home is a cost-effective way to cut heating and cooling costs, improve durability, increase comfort, and create a healthier indoor environment.