Blower Door Testing Services

A blower door test is used to measure the cubic feet per minute (CFM) at -50 Pascals, of CFM50, which depressurizes the dwelling and simulates 20-30 mph winds on each side of the building.

All intentional openings in the envelope, windows and exterior doors, are sealed, to depressurize the conditioned space within the envelope to -50 Pascals. Volume from conditioned attics and conditioned crawl spaces is included and considered part of the dwelling and should be included in the test.

The CFM50 is multiplied by 60 and divided by the volume of the conditioned living space. This calculates the ACH50, or air changes per hour at -50 Pascals. This number represents how many times the air within that dwelling will exchange with the outdoors at -50 Pascals. 

A blower door test is used to measure the building's infiltration expressed in ACH50 for residential energy code.