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Measuring your Homes Air Leakage with a Blower Door Test

The most effective and straightforward method to estimate a home’s air leakage is to place it under a pressure test and measure how much air it takes to maintain that pressure.  This is best accomplished with a blower door which is a powerful variable-speed fan temporarily installed in one of the home’s exterior doorways.  This  calibrated fan is linked to a device called a digital manometer which measures the air pressure difference between the interior and exterior of the house.

Blower door set up diagram
Blower Door Picture

With this diagnostic equipment depressurizing the house, we can estimate the amount of air loss in cubic feet per minute (CFM).  This measurement can then be converted into other useful quantities such as air changes per hour (ACH), or even the aggregate size of leakage area expressed in square inches or feet. The test is conducted with gas-fired appliances off and all exterior openings closed except the doorway being utilized to conduct the test.

Along with measuring the airflow we inspect the home for major sources of leakage by means of an infrared camera to pinpoint the areas requiring air sealing efforts and can often uncover other defects.


The test is conducted during the initial Home Performance Assessment and during a post work assessment to verify air sealing efforts were successful.


Call Sacramento Building Performance at 916-416-0676, or email us at info@sacsustainable.com to schedule a free consultation to discuss solutions to improve your homes comfort and energy performance.

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