Massachusetts Air Sealing Rebates

Air sealing is the process of identifying and sealing unintended gaps and cracks in the building envelope that allow conditioned air to escape. A contractor begins with a blower door test — a calibrated fan mounted in an exterior door that measures how leaky the house is. Common sealing locations include attic bypasses (around recessed lights, plumbing, and top plates), rim joists in the basement, and around electrical and plumbing penetrations in walls. Most air sealing visits take 2–4 hours alongside insulation installation, in the same contractor visit.

Air sealing and insulation are almost always done together through Mass Save — using the same participating contractor at the same appointment. In most cases you do not need to schedule separate visits. Air sealing prevents conditioned air from escaping through gaps in the building envelope. For heat pumps, a well-sealed home means smaller required equipment, better efficiency, and more even comfort. Mass Save often recommends air sealing before or alongside heat pump installation — and may require it for the whole-home rebate path.