Insulation in Brunswick, Maine

Insulation and air sealing in Brunswick

Brunswick runs to about 47 square miles and roughly 22,336 people. It sits about 22 miles northeast of downtown Portland. There are around 9,523 housing units here. The community dates back to 1739. We cover ZIP code 04011.

We have not logged a completed job in Brunswick yet. We would rather say so than put a number on this page that is not real.

The housing stock in Brunswick

The typical home in Brunswick dates to around the early-1980s. Houses of this vintage usually got batts or blown fiber at whatever the standard of the day was, which is well short of what is recommended now. Most are one top-up away from being right.

We work across Brunswick rather than one corner of it — Cooks Corner, Brunswick Landing, Merepoint, Bunganuc Landing, Pennellville, Dyer Corner, Growstown and Harding included. Construction and vintage change between them, sometimes by thirty years and a whole different framing method, which decides whether a wall can be dense-packed at all.

Brunswick sits at the north end of Casco Bay and at the head of tide on the Androscoggin River, whose falls powered up to 25 sawmills and Maine's first cotton mill in 1809. Bowdoin College and the Harriet Beecher Stowe House are here, and the town has four National Register historic districts.

Brunswick homes in the Census numbers

The Census Bureau estimates 9,523 homes in Brunswick. 1,860 of them (20%) went up before 1940 — 20th of 64 places on this site for pre-1940 housing. More of today's homes date from before 1940 than from any single decade since, and 48% predate 1980. For Cumberland County as a whole the pre-1940 share is 23%, so Brunswick sits below it.

Of 8,913 occupied homes, 21% heat with utility gas and 13% with electricity; another 15% burn propane or other tank gas. Electric heat here is less common than across the county (15%), and ranks 15th of 64 on this site. Whoever comes out will ask what heats the house first: the rebate is the same on any fuel, but the saving is not.

71% of occupied homes are owner-occupied and 52% of all homes are single-family detached houses, with 1,197 mobile homes in the count. With houses like these, the conversations we expect most are about the attic, which is where most houses here start.

9,523 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 8,913 occupied.

Sealing comes first in Brunswick

2,408 of Brunswick's 9,523 homes (25%) were built in the 1980s and 1990s. The gaps in houses of that age are the parts nobody sealed: batts stuffed into the rim joist, bare spots over cathedral and tray ceilings, soffit vents buried with no baffles, can lights punched through the ceiling plane. A top-up plus a day of sealing usually covers it.

What the energy code requires in Brunswick

Brunswick enforces the Maine Uniform Building and Energy Code (2021 IECC with Maine amendments). Brunswick's permit page says the 2021 codes, the International Energy Conservation Code among them, apply to permits applied for after April 7, 2025, while permits issued earlier follow the codes in effect when they were issued.

For new work, the attic number under that edition is R-60, with walls at R-30, or R-20 + R-10 continuous, or R-13 + R-15 continuous, or R-20 continuous. Set that against the Department of Energy, which recommends R60 for an uninsulated attic in this climate zone and R49 for one that already has a few inches.

Table R402.1.3 of the 2021 IECC for climate zone 6, with the wall row as Maine rewrote it (08-003 C.M.R.

Do you need a permit to insulate here?

Brunswick publishes no answer either way. Insulation and air sealing appear on neither the permit-required list nor the exempt list. The town's Planning and Development FAQ lets siding work go ahead without a permit when nothing structural changes, and says to check with the Codes Office first. We confirm it with the department before we start and pull whatever is needed. We would rather write that here than guess on your behalf.

Permits and inspections in Brunswick

The published number is 207-725-6660. The department page is here.

Permitting is on us, not on you.

Rebates a Brunswick homeowner can actually use

In Brunswick, 45% of occupied homes heat with fuel oil or kerosene, 15% with propane or other tank gas and 13% with electricity, and 21% utility gas (Census ACS 2020–2024). For Brunswick homeowners the rebate is Efficiency Maine's: $2,000 for each attic, wall or basement zone of 500 square feet or more at any income ($3,000 moderate, $4,000 low income), with $150 to $300 for attic air sealing on top. Only a Residential Registered Vendor can do rebated work, the claim goes in within six months, and a lifetime limit of $8,600 per home applies. Income-qualified households in Cumberland County can apply to Community Concepts Inc (207-795-4065) for free weatherization through MaineHousing instead. The Cumberland County page and the rebate guide carry the full rules.

Nearby

Brunswick borders Topsham, Freeport, Harpswell, West Bath, Bath and Durham. These are the ones we also cover, each with its own energy code and permit rule:

Elsewhere in Cumberland County we also cover:

How Brunswick compares with its neighbors

Maine sets the residential energy code statewide, so the attic figure is R-60 wherever it is published here; what changes is the permit desk, and 1 of the 7 publishes a permit rule for insulation.

All 25 Cumberland County jurisdictions side by side →

Common questions about insulation in Brunswick

Code and permit facts checked October 24, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: brunswickme.gov (2, 3, 4, 5, 6, 7, 8) · maine.gov (2) · en.wikipedia.org (2, 3, 4, 5) · zip-codes.com · tigerweb.geo.census.gov · efficiencymaine.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department at 207-725-6660 or Efficiency Maine at 866-376-2463 first.