How a Blower Door Test Can Help Improve Your Home Comfort and Indoor Air Quality

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Has your older Maine home been a bit drafty lately, or have you noticed an increase in dust throughout your home? Or maybe you’ve realized that your new home is costing you more than you estimated for utility costs, and your heating and cooling equipment are struggling to keep you comfortable. These are all signs that your Maine home is full of air leaks. 

Regardless of what is causing you to take notice of the air leaks in your home, you probably want to resolve the issue, and residential air leakage testing can be a great help. Blower door tests are the industry standard when it comes to whole-house air leakage tests, and they’re used to resolve home air leakage rates that are too high for optimum comfort and efficiency. Here is what you need to know about how they work and how you can benefit.

What Is a Blower Door Test and How Does it Work?

The blower door test was invented in Sweden in the ’70s and had shown up in American homes by 1979. The goal of a blower door test is to provide a reading of the total air leakage throughout a building, and this is done by attaching a large fan to an exterior door with a special pressure gauge device attached. 

A blower door is temporarily attached to a home using an airtight skirt made of a plastic material, then all other exterior doors and windows must be shut, while interior doors remain open. Once the set-up is complete, your blower door technician will turn the fan on to create a negative pressure inside the home (the fan blows the air out, not in). 

After a few adjustments to complete the pressure gauge readings, the blower door test is complete and your blower door technician will be able to assist you in understanding the findings!

Understanding Blower Door Test Measurements

When a blower door fan creates a negative pressure within your home, outside air is pulled into your living space through whatever pathways it can find. With all of your outside windows and doors shut, this only leaves tiny, hard-to-reach, and often invisible air leaks for outside air to travel through. At this point, the pressure gauge is measuring:

  • If your home is airtight enough to reach 50 pascals

  • How many times the air in your home is replaced with outside air (Air Changes per Hour, or ACH)

  • The resulting air leakage in Cubic Feet per Minute (CFM)

  • How much air infiltrates your home naturally, without the blower door

These measurements are used to understand how air moves freely into and out of your home. So, how can an experienced home performance contractor like Evergreen Home Performance use the results of your blower door test?

What Happens Next?

A blower door test is all a part of a greater home diagnostic service, called an energy audit, and the data is used to select the measures needed to increase the overall comfort and efficiency of your living space. Your Evergreen Home Performance Energy Advisor can utilize infrared thermal imaging during the test to help locate the air leakage locations. Then, when your Evergreen technician crew arrives to air seal, they seal them up until your home is as airtight as possible. This is called air sealing

Air sealing provides you with greater control over your indoor temperatures, and the blower door test data helps determine how much ventilation your home needs to keep it safe and healthy. Usually, existing home ventilation equipment (like range hoods and bathroom fans) can be optimized to do the job.

What’s more, the same infrared imaging can be used to locate areas of poor insulation. Replacing outdated or damaged insulation can increase the overall effectiveness of your home improvement project, and should be completed alongside air sealing. 

With proper air sealing  and insulation, your Maine home will be:

  • More comfortable

  • Healthier to live in

  • Less expensive to heat and cool 

  • Less drafty

Want to keep Maine’s unpredictable outside air away from your comfortable and healthy home? Schedule an energy consult with Evergreen at or get in touch here.

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Evergreen was so helpful in securing us Efficiency Maine funding for a big attic insulation project early this winter. They did all of the paperwork, and totally guided us through a vermiculite removal process that included a payment from a trust for the procedure. I could instantly feel the second floor being so much warmer than before. The boiler does not kick on nearly as frequently since they completed the job. It was worth every penny! Brian Robinson was so thorough throughout the whole process including a full walk through after the job had been completed.

Todd W.

Camden

"Working with Evergreen from start to finish was a great experience." See what our customers have to say about their experience with Evergreen Home Performance. 

Jeff L.

I was very impressed by the professionalism of this company and the workers. Brian R. was very prompt in replying to my questions; the crew was meticulous in all parts of the work and attentive to the safety aspects concerning Covid; and Brian was extremely thorough in the final inspection. My attic is now snug and warm and I've noticed that the second floor is warmer as well.

Julia S.

Rockland

Evergreen completed the work at my home thoroughly and professionally. An inspector from Efficiency Maine came to inspect afterwards and described it as "state of the art" and "outstanding". The crew was very pleasant and considerate during the project. Their cleanup each day was perfect. Communications with the office were easy and reliable. I am very satisfied.

Catherine H.

South Portland

First we have Evergreen do a BIG project worth about $20K (windows, basement, insulate & rebuild an entire wall, a door, attics, and air sealing). They were so great we had them come back later when we decided we did want to do our other door. They are professional and do great work. They take care of your home and are trustworthy, and on top of all that friendly! I highly recommend you call them!

Garreth C Debiegun

Led by Brian Robinson, the Evergreen Home Performance team just completed an insulation refit at my home. It was truly a great experience from start to finish, a period of time that was a fraction of the time that I originally anticipated due to the team's unbelievable work habits and professional knowledge of their tasks. As impressive were the communication skills and friendliness of each and every member of the team.

Anne W.

Rockport

I never leave reviews, but had a great experience with Evergreen and wanted to spread the word! In short, we worked with them to insulate our roof this winter and have noticed surprising immediate results. The constant ice dams I have wrestled with are completely gone, and the home is noticeably more comfortable. It's a little too early to tell if our oil bill is going to reduce, but I imagine we will see an impact there as well.

Joel W.

Portland

We absolutely loved our experience with Evergreen. The team was incredibly kind, professional and great to work with. We're very impressed with the quality of work of the Evergreen team and how easy they made everything! Our house had barely any insulation ahead of this project and the results are amazing. Insulating the attic, walls and basement with Evergreen allowed us to tear a 50-year-old furnace, ductwork and oil tank out of the basement and now heat the home with new heat pumps. Evergreen also added 100 sq ft of clean, new storage space to the attic!

Nick S.

South Portland

Update 12/2018: Evergreen has completed Phase II of my house (insulating and installing air/moisture barrier on exterior walls, replacing old windows) and now that heating season is upon us, the difference is astonishing. The house is tight as a drum and so easy to keep warm. Worth every penny. Thank you all! Working with Evergreen was a positive experience from start (no charge energy audit) to finish (a MUCH more comfortable home). Brian Robinson spent a lot of time with me on the audit, explaining clearly what he was finding in my ca.

Rebekah W.

Rockport

Awesome company. It was a few years ago that they did the audit and then we commissioned them to do the work. We subsequently sold our house and moved to South Africa, but their level of service and expertise will live on.

Odette Brown

Evergreen has insulated two homes that we've owned now and both times we experienced exceptional service and craftsmanship. Our rep, Justin, went above and beyond answering questions and the installation team was attentive to every detail, including pulling out old poorly installed insulation and redoing a bathroom fan that wasn't up to current code. They also left the place spotless every day! Our home is already so much warmer this fall and we are looking forward to using less oil this winter.

Eva G.

Falmouth

We initially contacted Evergreen through Efficiency Maine for an energy audit, which was conducted promptly and professionally by Justin McEdward, one of their Energy Advisors who is BPI-certified. After a thorough inspection of our newly purchased home, Justin explained in great detail what we needed and did not need. It was agreed that Evergreen would remove all of the existing attic insulation, which was not adequate, and replace it with blown in cellulose, to a rating of R-60.

Thomas W.

Scarborough

Very easy process, start to finish.  Friendly, professional, and really know their stuff.  They made some improvements to our condo and we were very happy with how it played out.  Would definitely recommend them.

Clayton Eames

I highly recommend Evergreen! 1st, I had a home efficiency inspection (that was free) & Bryan P. was great! He took the time needed, asked & listened to what I thought were priorities, explained clearly what he thought were priorities & why, then gave me numerous options. No pressure whatsoever. Then I had my attic sealed & insulated as the 1st step & Bryan came along on day 1 to introduce everyone & make sure we were all on the same page. Bruce's team (inc. Kelsey & Roland) did the work - they were exceptional!!

Melissa M.

Kennebunk

Thanks Evergreen Home Performance for helping to make our home more efficient. Many thanks as well to Bryan for the initial walk through and recommendations to make our home more efficient and to Dave, Roland, and Jacob for a job that was done professionally and courteous.  We were amazed at the level of efficiency and everyday they made sure to protect our floors, carpets, and furniture. We had daily discussions with Dave about progress and what was being done and where they were at in the project.

Carol Fink

Portland Buy Local
Efficiency Maine
EPA Lead-Safe Certified
Building Performance Association
BPI Certified