Blower Door & Duct Leakage Testing

A Blower Door Test (also known as Envelope Leakage) is performed by  installing a frame onto a central door in the home and attaching a fan  to the door. The fan depressurizes the home to a Pascal of 50. Once the  home is depressurized we use an instrument called a nanometer to measure  the difference in air pressure between the outside of the home and the  inside of the home. We get results in ACH (air changes per hour).

This  is the amount of time air leaks out of a home and new air enters into  the home in an hour. All homes leak and that’s normal but keeping air  changes to an acceptable amount is essential since each air change  creates a need to reheat or cool the new air.

A Blower Door Test must be used in conjuction with a Duct Tester to measure duct leakate to the outside.

Infiltration or uncontrolled air leaks is a consequence of the  number and size of cracks in the building’s thermal envelope (its floor,  walls, ceilings, windows, and doors)  and natural and mechanical air  pressure driving forces affecting the building.

Natural driving forces include wind, the “stack effect” (air motion in  buildings related to indoor-to-outdoor temperature difference and  height) and atmospherically vented appliances. Mechanical driving forces  include fans (such as exhaust and air handler fans), duct leakage, and  others.