What is a Blower Door Test and Why Do You Need One?

Before buying a home, you should consider calling a professional energy auditor to conduct a blower door test. It is an excellent way to determine how energy-efficient a building is (or isn’t). Since you likely want to conserve as much energy as possible, conducting a blower door test can help you cash in on your savings.

What is a Blower Door Test?

A blower door test is conducted by an energy auditor. It measures the airtightness of a building by checking for air leaks in the walls, doors, attics, and so on. It reveals issues that may result in higher energy bills as well as inefficient heating and cooling.

Energy auditors use a blower door, a fan-like mechanism that mounts into the doorframe. It depressurizes the home by pulling air out of the house. With the interior pressure lowered, outside air can leak into the home through cracks and openings.

What Does a Blower Door Test Reveal?

It’s important to note that no home is 100% airtight. The blower door test simply reveals how airtight the building is -- if the air leakage is significant, the energy auditor will suggest how you can improve your home’s energy efficiency.

What are the Kinds of Blower Door Tests?

There are two kinds of blower door tests. The first one is called single-point testing. It depressurizes the building to 50 pascals, which is similar to 20mph of wind hitting the structure from all sides.

The second kind of blower test is called multi-point-testing. It is considered a more accurate way of measuring a building’s airtightness, as it involves taking multiple readings at different pressures. It is more realistic considering that buildings are subject to both low and high pressures, depending on the environmental conditions.

How Long Does a Blower Door Test Take?

The actual blower door test takes anywhere between five to fifteen minutes, however, the entire process can take up to two hours. This is because a lot of preparation has to be done before the blower door can be powered up. Here’s what to expect during a blower door test:

1. The energy auditor will conduct a walk-through of the home to identify areas that may be drafty. They may ask you to accompany them around the home.
2. They will close the exterior doors and windows, keeping interior doors (e.g. bedroom doors and office doors) open.
3. They will put out all fires and remove ashes from the fireplace. They will also seal off the chimneys.
4. Combustible appliances will be turned off (e.g. gas heaters, space heaters, coal-burning stoves).
5. The energy auditor will measure the volume of airspace inside the home.
6. They will then engage the blower door and monitor the air pressure through the gauge.
7. Another auditor will conduct a walk-through of the home to check for “penetrations”. This happens when outside air still leaks into the home despite the presence of the blower door.

The blower door test can take several hours depending on the size and complexity of your home. You will usually be able to receive the results at the end of the test.

What Next?

Use the results of your blower door tests, along with your energy auditor’s suggestions, to address any problem areas. Doing this will make your home more energy-efficient, saving you hundreds of dollars on energy bills each year. After completing the upgrades, ask the energy auditor to conduct another blower door test to see if your home’s airtightness has improved. Call Beeson Mechanical Service at (317) 535-9338 to perform your blower door test!