What happens if you fail a blower door test?

What happens if you fail a blower door test depends on whether it is for mandatory code compliance or voluntary energy audit. For new construction, the International Energy Conservation Code requires blower door testing for certificate of occupancy, with limits typically 5 air changes per hour at 50 pascals in climate zones 1 and 2 and 3 ACH50 in zones 3 through 8. If you fail, meaning your home leaks more than allowed, the building inspector will not issue certificate of occupancy until you remediate and retest. You will need to locate leaks using smoke pencil, infrared camera, or by feeling drafts during blower door operation, then air seal common leak points such as attic penetrations, rim joists, window and door frames, electrical penetrations, and ductwork. Then you must schedule and pay for a retest, typically $200 to $400. Failure delays closing, increases costs, and can affect builder reputation. For existing homes doing voluntary audit, failing is not a penalty, it simply indicates your home is leaky and wasting energy, auditor will provide report with infrared images and recommendations for air sealing, after which you can retest to verify improvement and enjoy lower bills and more comfort.