Definition:
A blower door test determines how airtight a building is and how much heated or cooled air can escape through leaks. Blower door tests are performed by energy auditors.
Blower door tests require the following equipment: a powerful fan that gets placed into a temporarily sealed doorway, an air pressure gauge, and an airflow manometer.
The Department of Energy recommends a calibrated (versus uncalibrated) blower door for the test, because the calibration allows the energy auditor to determine precisely how much air is flowing through the house.