Air Sealing | Greater Portland, Maine
Most Maine homes lose 30–40% of their conditioned air through hundreds of tiny, invisible leaks. We find every one of them and seal them permanently. Often the fastest-payback home improvement available.
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Caulking a window frame is a weekend project. True air sealing is not. The leaks that account for 30-40% of your heat loss are hidden in attic floor penetrations, rim joists, and wall-to-floor junctions. Finding them requires a blower door to depressurize the house and reveal exactly where conditioned air is escaping.
A professional air sealing contractor uses calibrated diagnostic equipment to measure your home's baseline leakage, systematically seal every penetration, and verify the improvement with a post-work blower door test. Without the testing, there is no way to know whether the work addressed the right areas or achieved the target air change rate.
Horizon Homes is BPI-certified and has been an Efficiency Maine Top-Rated Vendor for 10+ years. Our crews are trained in building science, not just caulk application. We understand how air, heat, and moisture interact in Maine's cold climate, and we seal homes in a way that improves comfort without creating moisture or ventilation problems.
We also handle all Efficiency Maine rebate paperwork and deduct rebates directly from your invoice. No waiting for reimbursement.
We use diagnostic testing to find every leak, not just the obvious ones.
We depressurize your home with a calibrated fan to measure air leakage and identify exactly where conditioned air is escaping. Learn how blower door tests work as part of air sealing.
Our crew works through every penetration, bypass, and gap, using foam, caulk, and weatherstripping as appropriate for each location.
We run a second blower door test after sealing to measure the improvement and verify we've met the target air change rate.
"I had a cold corner in my living room for 10 years. After Horizon sealed the rim joists and attic bypasses, it was gone. The house feels completely different: no more drafts, no more cold spots. Wish I'd done this sooner."
"Working with Horizon Homes was a great experience. They were very detail oriented, extremely knowledgeable, and easy to work with. Was very impressed with their professionalism and communication skills."
"The blower door test was eye-opening. I had no idea how leaky my house was. After the sealing work, the difference was immediate. The house holds temperature so much better and the heating system runs less often."
Air sealing is almost always performed alongside insulation, so costs are usually bundled. Typical ranges before Efficiency Maine rebates:
Efficiency Maine rebates cover air sealing alongside insulation, up to $8,000 total depending on household income. We deduct rebates directly from your invoice. See the Efficiency Maine rebates guide for current amounts and income tiers.
Financing is available through Efficiency Maine's Green Bank starting at 0% APR. We walk through your options at the free assessment.
Detailed local pages for towns with specific housing types and common air sealing challenges:
Horizon Homes provides professional air sealing across Greater Portland and Southern Maine, including:
