What happens if you fail the blower door test?

What happens if you fail the blower door test depends on whether it is for code compliance or for energy audit. For new construction, most states require blower door test to meet International Energy Conservation Code limit, typically less than 5 air changes per hour at 50 pascals for climate zones 1-2 and less than 3 ACH50 for zones 3-8. If you fail, meaning your home leaks more than allowed, you will not receive certificate of occupancy until you fix leaks and retest. Builder must find and seal leaks, common leak areas include attic penetrations, rim joists, windows, and electrical penetrations, then pay for retest costing $200 to $400. Repeated failures delay closing and increase costs. For existing homes undergoing voluntary energy audit, failing is not punitive, it simply means your home is leaky and would benefit from air sealing, auditor will provide infrared images and list of leak locations to seal, and after air sealing you can retest to verify improvement. Failing also indicates higher energy bills, drafts, and potential moisture issues. So failure is diagnostic, not penalty, except in new construction where code requires passing before occupancy, so you must air seal and retest until you pass.