You are having a professional energy audit done in your home where the auditor will perform a blower door test.

You have a basic understanding of what the test is and how it relates to building science and energy efficiency, but how is a blower door testing in homes done?

RetroFoam of Michigan has been insulating homes with foam insulation since 2002 to help create an air seal. We are BPI certified, which means we have the knowledge and experience to run blower door test equipment and tell you where you could be leaking air in your home.

Now we’ll walk you through how a blower door test for residential customers is done.

Blower Door Testing in Homes

There are a few preliminary things that the person conducting the blower door test will need to do before setting up.

First things first, the person conducting the test will determine which door will be used in setting up the test, which is typically the front door. The test must be set up in an entrance that faces into the living space.

This means the test can’t be used on a door that goes into a garage because the opening needs to go right to the outside.

Once the correct door has been decided, the person conducting the test will walk around all levels of the house to make sure all of the doors and windows to the outside are closed and any inside doors are open. Essentially, all of the exterior doors must be closed and the interior doors open because the fan used in the test needs to pull air throughout the home.

That’s how the air leakage is tested, but more on that shortly.

Next, the person conducting the test will make sure the furnace is turned off. This is done so the furnace doesn’t kick on and throw off the results of the test.

Now it’s time to set up the test.

The blower door unit has a frame that is inserted into the doorframe. This frame can be adjusted to fit any size door. Once it is fitted to the correct size, the unit frame is tightened into place. Now the cover that will go over the frame is put into place. This cover shuts off and seals up the doorway.

There is a hole at the bottom of the cover and this is where the fan for the test is inserted. The fan is set up in the cover and hooked to a handheld device. This device reads the sensors inside the fan.

Once everything is all set up and hooked to the device, the square footage of the house is entered into the device. For an existing house, the person conducting the test will enter 50 pascals. The test is measuring airflow through the home in cubic feet per minute (CFM).

Once all of the data is entered, the fan is turned on. It will run for about 90 seconds to a couple of minutes until it reaches 50 pascals. The technician will then read the results.

A general rule of thumb is you want your CFM reading to be pretty close to the square footage of the house. So, if you have a 1,500-square-foot house, you want your CFM reading to be around 1,500 at 50 pascals.

If the results are above that, you are getting too much air into your home, which can be addressed by creating an air seal. If the CFM is under the ideal reading, that means you aren’t getting as much air exchange, which the fix can be as simple as turning on a bathroom fan or kitchen hood once a day.

The person conducting the test will help you determine where your home is experiencing air leakage and discuss how to fix them to make your home more energy-efficient and comfortable.

Creating an Air Seal in Your Home

Now that you know how a blower door test is done, you probably have a better understanding of how an air seal works in your home and why it’s important.

If you want a home that is more energy-efficient, creating an air seal is part of that equation. If you’d like to learn more about how foam insulation can help you with that aspect, check out the Learning Center on our website.