How to pass a blower door test?

How to pass a blower door test requires systematic air sealing during construction or renovation before the test is performed. The test measures air leakage at 50 pascals and most energy codes require less than 5 ACH50 in warm climates and less than 3 ACH50 in cold climates. To pass, focus on biggest leak areas first. Seal attic penetrations thoroughly, use caulk and spray foam to seal around plumbing vents, electrical wires, top plates, and recessed lights, and use airtight ICAT rated recessed cans. Seal rim joists in basement with closed cell spray foam or rigid foam sealed with foam. Seal all bottom plates, window and door rough openings with low expansion foam, not just fiberglass. Use continuous air barrier like drywall with sealant at edges, often called airtight drywall approach. Weatherstrip exterior doors and install door sweeps, ensure windows close tightly. Seal ductwork with mastic, especially in unconditioned spaces. Seal electrical boxes on exterior walls with gaskets and foam. Ensure fireplace damper closes tightly and seal chase. Use blower door during construction as diagnostic tool to find leaks with smoke pencil or infrared camera. Quality control matters more than expensive materials, attention to detail in sealing every penetration will help you pass easily and result in comfortable, energy efficient home.