Blower Door Testing

What Is A Blower Door Test?

A blower door test is used to measure air changes per hour in a home or building. Air changes in a home are normal and beneficial as old air is replaced with new fresh air. Too many air changes however, can be detrimental as each time the air changes over it needs to be reheated or recooled resulting in increased energy consumption issues. Excessive air changes can cause drafts and uncomfort resulting from air leaks and even mold, moisture and condensations issues in a home.

How Is A Blower Door Test Conducted?

To conduct a blower door test we first close all exterior doors and windows to the home and open all the interior ones. We find one central exterior door, open it and place an adjustable frame onto that door. Next we place a fan onto the frame which is used to depressurize the home to a Pascal of 50. A home depressurized to a Pascal of 50 is equivalent to having 20 mile an hour winds running inside of the home. Once the fan pulls air out of the house air begins to infiltrate the home more aggressively. We use an instrument called a nanometer to compare the fan pressure to the pressure inside the home and finally convert it to the amount of air changes per hour.

What Is A Passing Blower Door Test Score?

Southeastern Pennsylvania sites in climate zone 4 according to the 2015 IECC, (International Energy Conservation Code). In climate zone 4, a blower door test resulting in 3 air changes per hour or less is the acceptable amount of times air should be changed in the home. The state of Pennsylvania however, amended that number to allow up to 5 air changes per hour

Why Do I Need A Blower Door Test?

Both the States of New Jersey and Pennsylvania have now adopted the 2015 IECC, International Energy Conservation Code which requires blower door testing on all newly constructed residential units. We often work with home builders and contractors who require a blower door test in order to close out their final building permit. A duct leakage test may also be required if any of the units or ducts are located outside the buildings’ thermal envelope. Learn more about energy code compliance.

Homeowners will reap the most benefits from blower door testing. When the fan is used to depressurize a home the air that leaks into the home enters more forcefully making air leakage easier to identify and uncovering potential energy saving and home comfort opportunities. A blower door test takes only a couple hours to perform but can have a lifetime effect on the efficiency and comfort of the home. 

How To Pass A Blower Door Test:

  • Anticipate potential air leaks ahead of time.
  • Use the correct outside air barrier such as Tyvek or Zip Sheathing and making sure to tape the joints.
  • Insulate the home using the correct R Value and properly install the insulation material.
  • Ensure any penetration in the exterior of the home are caulked or use spray foam.
  • Doors and windows are property installed, caulked and weather sealed.
  • Penetration between conditioned and unconditioned areas such as basements, attics and crawl spaces are sealed.
  • Philadelphia provides a step by step checklist you can follow to make sure everything is done correctly. The sheet is below or you ou can download and print it by clicking here.
  • Local Energy Audits always has a thermal imager, weatherstriping, caulk and spray foam on our service vehicle. We scan the building with a thermal imager find the air leakage and seal them us.
  • Over 90% of the time we can achieve a passing score within two hours and will issue the necessary paperwork to close out the building permit.

How Much Does A Blower Door Test Cost?

For residential customers we price the blower door test at $390 which includes a walkthrough of the home with a thermal imager, finding issues and making recommendations on how to correct those issues.

For contractors we price the blower door test at $300 for one single home. That includes the test and the certificate you’ll need to present to the building inspector to close out your permit. For a duplex the price is $500. 

If you are outside our local service area we can still help you but there is additional cost for travel time which can be qouted over the phone.

If you are looking for multi unit testing for large project 4 tests to 300 we will bid the project to achieve a price which is comfortable for you.

To prepare for the blower door test we begin by turning off the heating and air conditioning system, bathroom fans and kitchen exhaust fans. Next we walk around making sure all exterior doors and windows are shut tight including ones to an unfinished basement or garage, any place outside the buildings’ thermal envelope. Once the house is ready we choose one centrally located exterior door and install the blower door frame and fan. We use the blower door fan to depressurize the house to a Pascals of 50.

Once the house is depressurized outside air will begin to infiltrate the home more aggressively making leaks easier to identify. We can use a thermal imager to easily identify problem areas by measuring temperature differences in any wall or ceiling which leads to unconditioned spaces.

We carry chalk, spray foam and weatherstriping and can work with the homeowner or contractor to correct obvious air leakage issues right there on site and retest to see if a desired score can be achieved. 

For contractors looking for a blower door test In most cases if a house has been insulated professionally those issues can easily be resolved with chalk and spray foam on site during the testing process. Over 90% of the time we can achieve a passing score within two hours and will issue the necessary paperwork to close out the building permit.

Interested In Our Services?

Call us at 215-857-9452 or email us at or send us a message on contact page.