ProcessUp to date · Jan 15, 2026
Blower Door Test
A diagnostic test that uses a calibrated fan mounted in an exterior doorway to depressurize the house and measure the total air leakage rate, expressed in CFM50 or ACH50.
Why It Matters
A blower door test quantifies exactly how leaky your home is. Results guide air sealing priorities and verify improvements. Target: 3-5 ACH50 for existing homes; 1-3 ACH50 for tight new construction.
Related Topics
Related Terms
Air Sealing
The process of identifying and sealing unintentional air leaks in a building envelope — including gaps around pipes, wires, ducts, windows, and the attic hatch.
Energy Audit
A professional assessment of a home's energy performance, including blower door testing, thermal imaging, duct leakage testing, insulation evaluation, and appliance efficiency review.