Blower Door Testing

Blower Door Testing

Drafty Rooms. Rising Bills. Freezing Pipes in a Newer Home. What’s Really Going On?

If you’re struggling with comfort issues or high heating costs, the problem might not be what you think. You can’t always see the cracks and gaps letting outdoor air sneak in—or the warm air slip away.

That’s why we use blower door testing: a powerful diagnostic tool that helps us measure your home’s air leakage, pinpoint energy waste, and recommend upgrades that actually solve the problem.

Whether your home is brand new or 100 years old, air leaks could be costing you money and comfort. We’re here to help you find them—and fix them.

Evergreen Team Conducting A Blower Door Test
Setting-up a blower door test in a house

What Is a Blower Door Test?

A blower door test uses a powerful fan installed in an exterior doorway to lower the air pressure inside your home. This forces outside air to rush in through cracks, gaps, and holes—revealing where your home is leaking air.

While the test runs, we use an infrared thermal camera to detect hidden problem areas behind walls, around rim joists, in the attic, and more. Summer’s a great time to conduct this test, as the leaks entering your living spaces from your attic or the outdoors are colored warm or hot, while the colder air leaking up from the basement or crawlspace will show up as cool on our cameras. 

The result? A detailed picture of your home’s energy performance—one that helps us target the right upgrades for maximum comfort and savings.

How Blower Door Testing with Evergreen Works

  1. We prepare your home: closing exterior doors and windows, opening interior doors, covering ashes in wood stoves and fireplaces, and turning off all combustion equipment.
  2. We install the blower door fan in one of your exterior doorways and turn it on, depressurizing your home.
  3. We measure the amount of air coming in to determine how “leaky” your house is.
  4. We then scan with a thermal camera to reveal the exact spots where insulation and air sealing are needed.

This is part of our full energy audit we use to design smart, effective insulation and air sealing upgrades.

Evergreen Blower Door Testing
Blower Door Testing

Why Blower Door Testing Matters for Your Home

A blower door test gives us data, not guesswork. That means smarter upgrades and measurable results.

With the insights from this test, Evergreen can help you:

  • Identify and seal hidden air leaks
  • Improve your home’s comfort and consistency
  • Cut down on heating and cooling bills
  • Reduce strain on your HVAC system, especially recently installed heat pumps and mini-splits
  • Protect indoor air quality by achieving the right balance of airtightness and ventilation

Blower door testing doesn’t just reveal when your home is too leaky—it can also show if it’s too airtight. In homes that have been over-sealed without proper ventilation, indoor air quality can suffer.

We use this information to make sure your home is healthy and recommend ventilation solutions if needed to keep your indoor air fresh, safe, and clean.

Plus, blower door testing is required for Efficiency Maine insulation rebates. We’ll do a pre-project test to establish a baseline and then a final test at the end to confirm the quality of our work and to prepare the final rebate application. 

Trusted Blower Door Testing for Maine Homes

From historic homes to newer builds in Rockland all the way down to Portland, we’ve tested—and improved—thousands of homes across Coastal and Southern Maine.

You don’t have to know whether blower door testing is right for your home—we’ll help you figure that out. Let’s talk about what you’re experiencing and decide on the best next step together.

Exterior view of a Maine Home

Call 207-594-2244 or contact Evergreen online to schedule your free consult.

Uncover the hidden air leaks making your home uncomfortable and expensive to heat.

BOOK YOUR FREE CONSULT

The folks at Evergreen did a great job fixing a rather major insulation problem in my house, which they helped identify with a great audit. When the work began, they were thorough, upbeat, and -- dare I say it -- efficient. I strongly recommend them.

Michael Williams

My husband and I bought a home on the water in Owls Head and decided to make the investment in Evergreen's recommendations for insulation. Brian Robinson spent 3 hours examining every nook and cranny before he made practical suggestions and explained them thoroughly to us.

Marie McNeely

Owls Head

Evergreen did an amazing job insulating our historic home. Their professional staff worked hard to ensure the tough areas in the attic were covered, and clearly communicated their progress. We are seeing the results with our discounted heating bills. Thank you, Evergreen!

Melissa Knoll

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 air sealing and reinsulating our 1890s basement and attic. It 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.

E Gallant

Kennebunk

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

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

Our basement was the eyesore of the house. I wanted to make improvements, but first needed to make structural, insulating and moisture mitigation improvements. Evergreen was professional and competent in taking on a complex project of not only encapsulation and insulation of basement and crawlspace, but completed needed improvements to the structural integrity of the wood floor platform above a crawlspace and brought in a concrete contractor to pour where there was once a rotting, tiered wood platform - replacing that area with a more functional and tight tiered concrete area.

Duane B.

East Boothbay

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

Evergreen has just completed Phase 2 of 2 at my home. They are professional, hard-working and courteous. They communicate well..no surprises. They've gone above and beyond to make my home comfortable and were very respectful of my home.I recommend them unequivocally!!!Many thanks to Brian, Brian, Rick, Eddie, Dawson and the rest of the Evergreen crew!!

David Henry Feldman

Great job installing windows and insulation.

Bob S.

Rockland

In the final stages of selling our home, and with a closing date set, an inspection came across an unanticipated issue in our attic. We quickly called in contractors, but nobody was able to identify the source of the problem. Then we thought of Evergreen. Brian Robinson was on site the next morning and immediately identified the source (a faulty roofing job completed three years earlier which had effectively sealed up portions of the ridge vent and restricted air flow - not easily visible with a quick inspection).

Robin McIntosh

Camden

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

We needed basement encapsulation to stop moisture coming up into the house from our regularly flooding basement. We had mold growing on windowsills and furniture. All the staff were friendly, respectful of our home, and easy to work with. Humidity has gone from 70% down to 40% and mold has not grown back after two months. Very grateful.

Sarah C.

Belfast

From beginning to end – that is from the moment Justin McEdward stepped into our home to assess our energy conservation needs until the crew left – the Evergreen Home Performance process went absolutely smoothly. Justin made a thorough inspection and took pictures with an infrared camera. His proposal described the scope of work in detail, and he explained what we could expect the proposed work to accomplish. Our proposal was forthcoming within a couple of days, and Justin was available to discuss it and answer questions.

Adrienne Harkavy

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