Insulation in Berwick, Maine

Insulation and air sealing in Berwick

Berwick runs to about 38 square miles and roughly 8,175 people. It sits about 38 miles southwest of downtown Portland. That is roughly 3,413 housing units. The community dates back to 1713. We cover ZIP code 03901.

Our job history shows nothing in Berwick so far. Plenty of sites will show you a number here anyway.

The housing stock in Berwick

The typical home in Berwick dates to around the late-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 Berwick rather than one corner of it — Berwick Village, Cummings and Diamond Hill 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.

Berwick, incorporated in 1713 as the ninth town in what is now Maine, sits on the Salmon Falls River and is joined by bridge to the mill city of Somersworth, New Hampshire, with which it has shared an economy since the 1800s. Diamond Hill, at 490 feet, is its highest point, and the former Prime Tanning property is the site of a mixed-use development announced in 2021.

Berwick homes in the Census numbers

The Census Bureau estimates 3,413 homes in Berwick. 545 of them (16%) went up before 1940 — 35th of 64 places on this site for pre-1940 housing. The 2000s were the busiest decade, adding 913 of today's homes (27%); 31% predate 1980 and 37% were built in 2000 or later. For York County as a whole the pre-1940 share is 20%, so Berwick sits below it.

Of 3,367 occupied homes, 2% heat with utility gas and 7% with electricity; another 17% burn propane or other tank gas. Electric heat here is less common than across the county (10%), and ranks 42nd 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.

87% of occupied homes are owner-occupied and 74% of all homes are single-family detached houses, with 430 mobile homes in the count. Read together, those numbers point toward air sealing on newer houses that already have depth.

3,413 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 3,367 occupied.

Sealing comes first in Berwick

1,104 of Berwick's 3,413 homes (32%) 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 Berwick

Berwick enforces the Maine Uniform Building and Energy Code (2021 IECC with Maine amendments). Berwick's Code Enforcement page names the state code as the town's building code without giving an edition; the state's 2021 editions have applied since April 7, 2025.

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.

The 2021 IECC, Table R402.1.3, zone 6, as amended by Maine's energy rule, 08-003 C.M.R.

Do you need a permit to insulate here?

There is no published answer for Berwick. Neither the permit-required list nor the exemption list mentions insulation or air sealing at all. That silence is not permission and it is not a prohibition. We settle it with a phone call before the crew is scheduled.

Permits and inspections in Berwick

The published number is 207-698-1101. The department page is here.

Permitting is on us, not on you.

Rebates a Berwick homeowner can actually use

59% of the occupied homes in Berwick burn fuel oil or kerosene for heat, 7% use electricity and 17% propane or other tank gas, and 2% utility gas (Census ACS 2020–2024). For Berwick 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. It applies to work completed on or after October 1, 2026 by one of its Residential Registered Vendors, and an attic qualifies only if it starts at R-21 or less. Income-qualified households in York County can apply to York County Community Action Corp (207-324-5762) for free weatherization through MaineHousing instead. See the rebate guide for the tiers and the checklist, and the York County page for the county.

Nearby

Berwick borders North Berwick, South Berwick, Lebanon, Somersworth, New Hampshire, Rollinsford, New Hampshire and Rochester, New Hampshire. These are the ones we also cover, each with its own energy code and permit rule:

Elsewhere in York County we also cover:

How Berwick 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 none of the 7 publishes a permit rule for insulation.

All 29 York County jurisdictions side by side →

Common questions about insulation in Berwick

Code and permit facts checked October 24, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: berwickmaine.gov (2, 3, 4, 5, 6, 7) · maine.gov (2) · en.wikipedia.org · www2.census.gov (2, 3) · prd-tnm.s3.amazonaws.com · efficiencymaine.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department at 207-698-1101 or Efficiency Maine at 866-376-2463 first.