The professional energy auditors use the Blower Door Test to identify the air-tightness of a house. The blower test during the energy audit of a house is very important for the following reasons. 

  • Avoiding the moisture condensation issues
  • Minimizing energy consumption because of leakage
  • Identifying the amount of mechanical ventilation needed for better indoor air quality
  • Preventing the uncomfortable drafts caused by air leakage

How does The Blower Door Test work?

The blower door is the huge, powerful fan mounted on the frame of the exterior entry door. The fan’s job is to extract the air out of the house and minimize the air pressure inside. The high air pressure outside the house flows in via openings and unsealed cracks. The auditors use a smoke pencil to mark the air leaks. With the test, the air infiltration rate is evaluated. 

The blower door comprises a flexible panel and frame that fits in the doorway. It is a pressure gauge to gauge the pressure differences outside and inside, variable speed fan and airflow manometer, and hoses for gauging the airflow. 

Preparing for the Blower Door Test

Here is the list of steps to prepare your house for the Blower Door Test. 

  • Remove all the wood from the fireplace, even the coals, before the auditor arrives for the test.
  • Walkthrough with the auditor across your house and point out the areas you are aware of leakage.
  • Ask the auditor to access all your house areas, including built-in cabinets, closets, attics, crawl spaces, and other unused rooms.
  • The auditor may ask you to close all exterior windows and doors, close fireplace dampers, open interior doors, close woodstoves, doors, and air inlets.
  • The auditor will also set controls on atmospheric fossil fuel appliances to avoid catching fire during the audit. The auditor would return the appliances to their original place after the test is done successfully.

The test usually takes 1-2 hours. It may increase depending upon the complexity of the house and air leakage found in your house.