Blower Door Testing

A blower door test measures how much air moves through gaps and openings in the home’s exterior enclosure.

During testing, a calibrated fan is temporarily installed in an exterior doorway and used to create a controlled pressure difference between the interior and exterior of the home. Diagnostic instruments then measure the home’s overall air-leakage rate.

Blower door testing may be helpful for:

• Identifying excessive air leakage

• Investigating drafts and comfort concerns

• Evaluating the effectiveness of air-sealing improvements

• Comparing performance before and after renovations

• Understanding potential energy-loss areas

• Supporting certain Energy Code Compliance requirements

• Gathering additional information before purchasing or improving a home

The test measures overall leakage. It does not automatically identify every individual leakage location, although additional investigation may help locate significant areas.

Testing may be affected by weather, open combustion appliances, incomplete construction, missing windows or doors, and other site conditions.