Blower Door Test

What is a Blower Door Test?
Blower Door Tests help determine a home's airtightness. Establishing a home has the proper airtightness can help:
  • Reduce energy consumption due to air leakage
  • Avoid moisture and condensation problems
  • Avoid uncomfortable drafts caused by cold air leaking in from the outdoors
  • Make sure that the home's air quality is not too contaminated by indoor air pollution.
How does it work?
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. A smoke stick may also be used to detect air leaks. These tests determine the air infiltration rate of a building.
Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for measuring airflow.
A Blower Door Test may also be used in conjunction with thermographic scans. This specialized infrared technology allows you to see air leaks through the camera's viewfinder.
How to Prepare for a Blower Door Test

Take the following steps to prepare your home for a Blower Door Test:

  • Close and lock windows, exterior doors and open interior doors
  • Turn down the thermostats on heaters and water heaters
  • Remove or cover ashes in wood stoves and fireplaces with damp newspapers
  • Shut fireplace dampers, fireplace doors, and wood stove air intakes.