Blower Door Test

Blower Door Test

Blower door tests are an important test in a professional energy auditor’s toolbox in determining exactly where your home might not be as energy efficient as it could be. A blower door test measures the exact air tightness of your building. When combined with other tools a professional auditor uses, the leaky areas can be identified and solutions to a drafty home can be discovered.

set up of a blower door during an energy audit

Benefits of the Blower Door Test

  • Identify how much air leakage a building in order to reduce wasted energy
  • Help avoid moisture condensation problems by ensuring proper air tightness.
  • Identify areas where cold air from outside is entering the home causing uncomfortable drafts
  • Ensure healthy indoor air quality by identifying areas where indoor air pollution might arise.

How a Blower Door Test Works

“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.” – Federal Department of Energy

A blower door uses powerful fan mounted into the frame of an exterior door. The blower door fan sucks air out of the building which lowers the air pressure inside the building. Because the outside air pressure is then higher than inside, air flows in through all unsealed cracks and openings. This process allows the energy auditor to gain valuable insight how airtight the building is.

a diagram of how a blower door test works

Collecting this information from a blower door test ultimately allows the energy auditor to design energy efficiency solutions that will fix the drafty areas and ensure your heating and cooling costs are minimized.

When the airflow and air pressure of a building are controlled, it becomes possible to measure exactly how airtight a building is. This is called the air filtration rate. The variables that determine the air filtration rate are pressure, flow and leaks. By controlling the air pressure and airflow the blower door assists in finding the leaky areas of a building.

The blower door test measures the air filtration rate of the building. By measuring the air filtration rate of a building an energy auditor can determine how leaky the building is or in rare cases if the building is too tight. With the house pressurized from a blower door, the energy auditor can then use additional tools such as a smoke pencil to identify precisely where the building is too leaky or drafty.

Marin Blower Door Test

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