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.

Is your home drafty and full of air leaks?

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Evergreen is a terrific company to deal with. Polite and efficient crews, meeting deadlines and major reduction in our heat bills. They corrected a lot of issues we suffered from doing work with a shoddy building contractor. We would recommend them to anyone.

Mary Carey

This team of individuals was professional at all times. They set up barriers that kept the dust at a minimum. They conducted an air flow audit and cut the draft circulation from the outside in half by sealing cracks. They hauled out the old insulation and replaced it with blown in insulation with an R - 60 Value. They also did the rebate paperwork so that I could get my $1500.00 rebate from the state of Maine. I highly recommend Evergreen Home Performance!

Daniel B.

Rockland

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

I made the mistake of NOT hiring this company last year when I bought and renovated my home. I have brought them in now and what a difference. This group knows what they are doing. They take a complete look at everything and believe they can make your home more energy efficient. They are very professional in the way they approach problems and solutions. And they find ways to save me money. Don't bother with anyone else. Bring Evergreen in before you do anything. Let them assess your issues and give you the right solutions.

Shaw

Owls Head

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 Home Performance shows its expertise from start to finish. Evergreen did three house projects in winter/spring/summer 2020 for me, attic insulation, crawl space under a porch insulation, and basement foam/vapor barrier. From my initial discussion with Bryan, I understood the reasons for choosing different types of insulation, the associated costs, and time estimates. Evergreen scheduled in advance, came when they said they would, and the crews were highly professional in their work and demeanor.

Iris S.

Portland

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

We had Evergreen Home Performance of Rockland come in to make our home more energy efficient, and what a TOP notch crew. Brian and his crew did an amazing job from start to finish. Very knowledgeable and professional. We would Definitely highly recommend this crew to anyone who is looking for energy efficiency in their home with a company that truly is an expert and knows how to do a quality job and truly cares about their customer.

Melissa S.

Owls Head

We just finished a large project of air sealing and reinsulating our 1890s basement and attic which had been completely renovated 8 years ago but still felt cold and lacked proper energy assessment and corrections. We met with Justin in December and were very impressed with his knowledge, professionalism and communication skills and knew Evergreen was who we wanted to work with. Dave was our on hands project manager and was excellent. The office staff has been quick to respond and helpful as well when needed.

Emily Gallant

Evergreen has a professional and reliable team of people who do excellent work. If you want the best of the best in the area, select Evergreen to accomplish your insulation needs.

Mary E.

St. George

Thorough, smart, informative, integrated, and communicative -- that's how my experience was with Evergreen even with the covid interruption midstream. The team picked up where they left off, insulated basement and air sealed attic and knee wall in 100' temps under the eaves! This business group was a pleasure to work with.

Karen W.

Gray

Evergreen listened and produced a thoughtful evaluation, proposal and comprehensive plan for our attic and basement. They exhibited excellent workmanship, teamwork, and came back as planned after the completion of the job to test the outcomes. Their overall performance as insulation and home improvement contractors is truly outstanding and we highly recommend them.

Susan S.

Saco

Our house still the most efficient home we’ve ever lived in. And we have you folks to thank for that! A special howdy to Brian Robinson please!

Bruce O’Donal and Eva Butler

The Evergreen Team did a fabulous job and was very tuned and responsive to the particular needs we had. The job was done right on budget and we are thrilled with the improved warmth and energy efficiency.

Ira M.

Rockland

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