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.

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

The Evergreen Team did a fabulous job, well exceeding our expectations, In just over a week they transformed our very drafty, noisy 213 year old house into a snug, draft-free, quiet haven with warm floors! The team was prompt, did everything they said they'd do and more. We are thrilled!

Trudy M.

Bridgton

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

They were highly recommended. I found them to be very knowledgeable and so helpful, with practical ideas. Despite my not living within their service area, they were generous with their knowledge, describing the usual solutions to correct leaks in my basement, and what the result is likely to be by following path A, B or C, and why. I was discouraged. Talking with Evergreen helped me see that my basement problems are far from insurmountable and really, fairly common in 100-year old homes. There are proven solutions.

Rosalind J

Damariscotta

I would recommend Evergreen wholeheartedly because of their professionalism, their follow through, and thoughtful project planning.

Jennifer A

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

Great company. Very professional and thorough. They take the time to explain everything and offer options to fit your budget. Wonderful experience from start to finish.

Bonnie Eustace

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 cant say enough about this company and the benefits that it created for our family. They are very professional and have effectively re-insulated our home. The heating bill proves the point.

Bob O.

Springvale

The crew members from Evergreen Home Performance each made sure to greet us every day, while maintaining their distance in this time of the pandemic. Their work took a total of nine days, spread over three weeks. Even though they were working in multiple rooms of our house, as well as the basement and attic, they were unobtrusive and always cleaned up after themselves every day. The on-sight manager kept us informed of their daily schedule so we'd know which parts of the house they'd be working on.

Bob & Sue

Whitefield

"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.

The Evergreen crew who installed insulation in my attic were fantastic! They were very professional, worked exceedingly hard, and they did an excellent job. They were very pleasant and friendly to be around. They cleaned up beautifully after each work day, and left my home in great shape on when they walked out the door for the last time. I can't believe they were able to accomplish all that they did with heat soaring into the 80s and 90s. It was pretty unbearable up there! They have my highest praise and my gratitude.

Cynthia F.

South Portland

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 are so pleased with the work the team from Evergreen Home Performance did in our home. The project included encapsulation of our basement with a reinforced vapor barrier, installation of a sump pump, spray foam insulation on the walls and insulation of the heating duct work. Everyone at Evergreen was friendly and professional. The project was completed on time and in budget. Our home is much cozier and warmer since the project was completed.

Linda Metzger

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

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