Air Sealing

Air Sealing

You deserve to feel comfortable all year long in your house. Air sealing and insulation locks in the warmth you’ve already paid for and stops drafts.

Most Maine homes have hidden gaps where indoor air escapes and unwanted outdoor air gets in. That air leakage makes your home harder to heat and cool, more expensive to run, and less comfortable to live in. Similar penetrations can also introduce basement and crawlspace air that’s been contaminated by moisture, radon, and unpleasant smells into your living spaces.

Evergreen Home Performance is a local insulation and air sealing company helping homeowners throughout Portland, Rockland and the surrounding Southern and Coastal Maine areas fix these problems at their source. Air sealing is an essential part of home insulation upgrades and a cost-effective energy efficiency improvement.

  • Eligible for up to $8,000 in Efficiency Maine rebates
  • Reduce drafts, improve home comfort
  • BPI-certified experts using building science-backed solutions
Hands using an air sealing gun to apply caulk to gaps in attic
air sealing attic

Why Air Sealing Matters

  • Stay warmer in winter, cooler in summer
  • Eliminate uncomfortable drafts
  • Lower your energy bills
  • Improve indoor air quality

Combined with insulation, air sealing creates a powerful barrier between the living spaces in your home and the outdoors.

In addition to energy waste, leaky homes often pull in air from crawlspaces, basements, attics, and wall cavities—along with dust, mold spores, radon, and other pollutants. Sealing leaks gives you more control over your indoor air quality and along with proper ventilation can create a healthier, safer environment for your family.

How We Find the Leaks: Blower Door Testing & Thermal Cameras

Many times newer homes, including really nice ones built before Maine building codes adopted a blower door testing standard, are leaky due to confusion about roof venting and side attics. If you have a newer home and the floor over the garage is cold or pipes freeze in the master bathroom, you could have an air sealing problem that can be diagnosed with a blower door test.

Blower door testing and thermal imaging cameras show us exactly where the air is escaping. We use this building science technology during our energy audits so we can seal the right spots for real results. We then run a blower test again after work is completed to confirm the difference your upgrades made!

Evergreen Home Performance Team Air Sealing Attic

Evergreen – The Leading Air Sealing & Insulation Company Near You

  • More than 4,500 Maine homes improved since 2006
  • More BPI-certified professionals than any other Maine contractor
  • Over 15,000 home energy audits completed
  • More Efficiency Maine insulation rebates secured for customers than any other contractor in 2024
Evergreen Home Performance Team Air Sealing In Attic

Attic Air Sealing

Attic air sealing helps slow the stack effect, where warm air escapes out of the top of your home and cold air is pulled in from your basement or crawl space to replace it.

Common areas we air seal in Maine attics include:

  • Attic hatches and access doors
  • Chimney chases
  • Side attics (particularly in Cape Cod-style homes of all ages)
  • Lighting fixtures, fans, and vent penetrations
  • Plumbing and wiring penetrations
  • Wall top plates and framing joints

After air sealing, we blow in cellulose insulation for comprehensive attic protection.

Basement & Crawlspace Air Sealing

Your basement or crawlspace is another major source of air infiltration and leaks in your home. In these areas, we often use some combination of rigid foam board and foam gun insulation, which is both an insulator and an air sealant, giving you maximum protection as well as moisture resistance.

Common areas we air seal in Maine basements include:

  • Rim joists
  • Foundation walls
  • Bulkhead doors and access hatches
  • Chimney chases and other floor penetrations
  • Gaps around pipes, wires, and vents

Air sealing and insulation is just one component of our basement waterproofing services. When combined, these solutions not only stop air leaks but also protect your basement from moisture and mold.

Encapsulated Crawl Space
Evergreen employees in attic

Airtight & Healthy: Why Ventilation Matters

As we reduce leaks and block outdoor pollutants with air sealing, we also make sure your home has enough airflow and proper ventilation. Without it, moisture and everyday pollutants originating inside your home—from cooking, showering, or just breathing—can build up.

This additional step ensures your Maine home is not just efficient—but safe, healthy, and comfortable too.

Save On Air Sealing with Efficiency Maine Rebates & Other Incentives

We helped more Mainers qualify for Efficiency Maine insulation and air sealing rebates than any other contractor in 2024!

  • Up to $8,000 in Efficiency Maine rebates
  • Financing with payments as low as $50/month through Efficiency Maine Green Bank and NEIF

During your free consult, we’ll tell you all about available Maine energy efficiency loans and rebates, helping you maximize your savings.

Evergreen Team Reviewing Tax Credits and Incentives With Homeowner

Ready to make your home feel as comfortable as you want? We’re here to guide you every step of the way. Call 207-594-2244 or contact us today to book your free consult.

Take charge of indoor drafts and expensive energy bills

Evergreen is your guide on the path to a better home.

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

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

Nothing but good things to say. The guys that came and did the actual work were extremely nice and did a great job. The energy audit was thorough and I was presented with multiple improvement options, I was even given ideas for improvement that Evergreen didn't offer. I never felt like I was being "sold".

Ryan Adams

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

Very Satisfied with the work performed by Evergreen. Professional employees, high quality work done in a timely manner. My sales rep was Justin, and he was phenomenal During the initial walk around my house, he gave me great ideas for how to improve the efficiency of our home. We will consult with Evergreen for our future home projects.

Adam G.

Westbrook

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

Evergreen came back this year to finish insulating our house. We have been remodeling and renovating an 1850s cape for several years. Their employees are very professional and pleasant to deal with. Over several years Brian Robinson has been able to schedule us in for several small areas that needed addressing and finally turning a room we used to close off in the winter into a comfortable usable space. We primarily heat with wood and since Evergreens great work our furnace has only come on ONCE this winter. Fantastic. Really satisfied customer in Thomaston.

Chris F.

Thomaston

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

I used to spend winters in the bathtub because my house was so cold. This was my first winter roaming around my whole house comfortably. This even led me to decorate a little. My heating oil usage has been reduced by over a quarter: I rarely have to boost the thermostat because the temp stays at a constant. The Efficiency Maine rebates, together with the energy savings, make it affordable for me to pay for the loan I took out to finance the project. I do not worry about my pipes freezing.

Claire Helene Bevan

Camden

I cannot say enough great things about working with Evergreen Home Performance. Everything including the initial consultation, the fabulous work crew, the office support and the final resolution was handled in a caring and professional manner. My only regret is that I did not know about them earlier. I enthusiastically recommend Evergreen to anyone with concerns about home energy use.

Darlene R

Bath

The team members were very professional, worked very hard, paid very close attention to detail and cleaned up meticulously every day. I really appreciated the care they took knowing the smallest details were going to make a big difference to our heating bills. Thank you!

Pam B.

Brunswick

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

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

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

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

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