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What Is A Blower Door Test Used For?

May 16th, 2025

2 min read

By Kilian Agha

You heard you need a blower door test but have yet to learn why. What’s the point of blower door testing? Why is it required for new construction homes?

South Central Services is certified to administer blower door tests. We service towns near Gettysburg, PA, and Leesburg, VA. We got our blower door certification because these tests are invaluable for new and existing homes.

By the end of this article, you’ll know:

  • What blower door tests measure
  • Why blower door tests are required
  • What a blower door test can tell you about your home

Blower Door Tests Measure Air Changes Per Hour.

From a technical standpoint, blower door tests are a carefully calibrated measurement of air changes per hour (ACH). The house can be pressurized or depressurized by installing a blower door fan in the main entryway.

Specialized equipment then measures how much air leaks out of the home (if pressurized) or into the home (if depressurized).

A technician from South Central Services completing a blower door test on a new construction home.

Without blower door testing, there would be no way to quantify air leakage.

New Construction Homes Need To Be Energy Efficient.

The International Energy Conservation Code (IECC) requires new homes to have minimal air leakage. In older construction, air leaks were considered normal and a part of letting a house “breathe.” As construction science has developed, we’ve discovered that air leaks contribute significantly to home energy waste.

Blower Door Tests Determine If New Homes Are Airtight Enough.

A blower door test is one of the tools used to confirm that new homes won’t waste excessive amounts of energy. If a new construction home doesn’t have enough air-sealing in the thermal envelope, the blower door test will reveal the air leakage in its results.

When new homes don’t pass a blower door test, air-sealing measures should be taken in the thermal envelope. The home can be tested again once the air leakage has been addressed.

Existing Homes Can Use ACH Testing To Measure Air Leakage.

Blower door tests are not restricted to new construction alone. A blower door test can measure air leakage in any home or building.

For many homeowners in older houses, blower door testing is used as a launching point for other energy efficiency upgrades. By investing in ACH testing, you can discover how leaky your home is and where the leakage is coming from.

The Bottom Line About What Blower Door Tests Are Used For

Blower door tests are used to quantify air changes per hour (ACH) in buildings. Most commonly, these tests are used in new construction homes. The IECC mandates blower door testing for new build houses. However, blower door tests can also be administered in existing homes to identify and quantify air leakage.

Now that you understand what blower door tests are used for, your next step is to:

Disclaimer: While we strive to publish information accurate to building science, local building codes and standards supersede our recommendations.

Kilian Agha

Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends.