Blower Door Test

Metrics and Efficiency Ratings - Home Energy and Building Envelope pillar

Also known as: blower-door test, ACH50, air leakage test

A diagnostic test that measures a home's air leakage by depressurizing it with a calibrated fan in an exterior door. Result expressed as ACH50.

A blower door test installs a calibrated fan in an exterior doorway and depressurizes the house to 50 Pascals (about a 20 mph wind). The fan's airflow at this pressure is the leakage rate. Result is reported in ACH50 (air changes per hour at 50 Pa) or in CFM50. Ontario building code references blower door results for new-construction airtightness compliance. Save on Energy Home Renovation Savings rebates require pre- and post-retrofit blower door tests by a NRCan Registered Energy Advisor. Typical pre-1990 Ontario home: 4-8 ACH50; ENERGY STAR new home: under 2.5 ACH50; Passive House: under 0.6 ACH50.

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