Do new homes need blower door tests?

Yes, new homes need blower door tests both because building codes require them and because they verify quality and performance that cannot be verified visually. Since the 2012 International Energy Conservation Code, blower door testing is mandatory for new residential construction in most states, requiring 5 air changes per hour at 50 Pascals in climate zones 1 and 2 and 3 ACH50 in zones 3 to 8, and 2021 code tightens enforcement. The test must be done by a certified third party before certificate of occupancy. Beyond code compliance, new homes need blower door tests to ensure builder actually air sealed properly, because even new homes can be surprisingly leaky if sealing at top plates, penetrations, windows, and rim joists was missed, leading to drafts, high energy bills, moisture issues, and HVAC sizing problems. Testing also determines whether mechanical ventilation like ERV is needed, as very tight homes below 3 ACH50 need fresh air ventilation per ASHRAE 62.2 to maintain indoor air quality. For buyers, a blower door test provides objective proof of envelope quality and can catch construction defects early when they are cheaper to fix, making it highly recommended even where not strictly required by local code.