Insulation in Hollis, Maine

Insulation and air sealing in Hollis

Hollis runs to about 32 square miles and roughly 4,872 people. It sits about 18 miles west of downtown Portland. There are around 1,944 housing units here. The community dates back to 1798. We cover ZIP code 04042.

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

The housing stock in Hollis

The typical home in Hollis dates to around the late-1970s. Postwar building here often meant three or four inches of fiberglass and no attempt at air sealing. If nobody has touched it since, that is what is still up there.

We work across Hollis rather than one corner of it — Hollis Center, Bar Mills, North Hollis, West Hollis, South Hollis, Bonny Eagle, Clarks Mills, Salmon Falls and Tylers Corner 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.

Hollis is a rural bedroom community of Portland along the Saco River, where water-powered mills once ran at Hollis village, Bar Mills, Moderation Falls, North Hollis and Bonny Eagle Falls. It was incorporated in 1798 as Phillipsburg and later renamed Hollis.

Hollis homes in the Census numbers

The Census Bureau estimates 1,944 homes in Hollis. 391 of them (20%) went up before 1940 — 24th of 64 places on this site for pre-1940 housing. The 1970s were the busiest decade, adding 453 of today's homes (23%); 58% predate 1980 and 21% were built in 2000 or later. For York County as a whole the pre-1940 share is 20%, so Hollis sits level with it.

Of 1,789 occupied homes, 1% heat with utility gas and 7% with electricity; another 15% burn propane or other tank gas. Electric heat here is less common than across the county (10%), and ranks 44th of 64 on this site. Efficiency Maine's insulation rebates do not depend on the fuel or the utility, but the fuel decides what the work saves, so the assessment asks how the house is heated.

88% of occupied homes are owner-occupied and 83% of all homes are single-family detached houses, with 190 mobile homes in the count. On a housing mix like this, the likely starting points are an attic top-up over postwar fiberglass.

1,944 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 1,789 occupied.

Sealing comes first in Hollis

411 of Hollis' 1,944 homes (21%) 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 Hollis

Hollis enforces the Maine Uniform Building and Energy Code (2021 IECC with Maine amendments). Hollis's building code is its Ordinance Enforcing the Maine Uniform Building and Energy Code, and the Code Enforcement page lists the 2021 International Energy Conservation Code.

Under that edition the required attic value for new work here is R-60, and walls R-30, or R-20 + R-10 continuous, or R-13 + R-15 continuous, or R-20 continuous. For comparison, the Department of Energy recommends R60 for an uninsulated attic in climate zone 6A, where Hollis sits, and R49 where there are already a few inches up there.

The 2021 IECC insulation table (R402.1.3), climate zone 6; Maine's energy chapter changed the wood-frame wall entry and left the attic at R-60.

Do you need a permit to insulate here?

Hollis publishes no answer either way. Insulation and air sealing appear on neither the permit-required list nor the exempt list. Section 7.A.1 of the Hollis Building Code lets normal maintenance go ahead without a permit unless plywood, sheetrock or framing is replaced, added or removed, in which case a permit is needed; insulation itself is not named. 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 Hollis

The published number is 207-929-2251. The department page is here.

Permitting is on us, not on you.

Rebates a Hollis homeowner can actually use

65% of the occupied homes in Hollis burn fuel oil or kerosene for heat, 7% use electricity and 15% propane or other tank gas (Census ACS 2020–2024). For Hollis 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. Every condition is in the rebate guide. The York County page compares the towns.

Nearby

Hollis borders Limington, Standish, Buxton, Dayton, Lyman and Waterboro. These are the ones we also cover, each with its own energy code and permit rule:

Elsewhere in York County we also cover:

How Hollis 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 Hollis

Code and permit facts checked October 24, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: hollismaine.org (2, 3, 4) · maine.gov (2) · en.wikipedia.org (2) · www2.census.gov (2) · prd-tnm.s3.amazonaws.com · efficiencymaine.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department at 207-929-2251 or Efficiency Maine at 866-376-2463 first.