I’ve talked about blower-door testing several times on Green Building Advisor and on my blog, Northern Built. This discussion will dive deeper into when testing should be done, the different testing options, and interpreting the results.
I typically perform four tests: One for code compliance, one during construction, one for contractor diagnostics, and one for homeowner diagnostics. Sometimes I’ll do a fifth test to help identify air leaks.
Code-compliance testing is the most common type of test I conduct. The building code from the 2018 IRC, which applies only to new construction, states:
The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding 5 air changes per hour in climate zones 1 and 2, and 3 air changes per hour in climate zones 3 through 8. Testing shall be conducted in accordance with RESNET/ICC 380, ASTM E779 or ASTM E1827 and reported at a pressure of 0.2-inch w.g. (50 pascals.) Where required by the building official, testing shall be conducted by an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the building official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope.
This code requires all new residential construction pass an air-leakage test of less than 5 or 3 air changes per hour (depending on your climate zone) at 50 pascals. This is a pass/fail test, and is typically performed at the end of construction after all HVAC equipment and plumbing fixtures have been installed. (Plumbing traps should be duct-taped or filled with water prior to running the test—if left open, air will be pulled through the system from the roof vent.) This is the least expensive of all the blower-door tests I conduct;…