How much insulation the law actually asks for on your street, who pays you to put it in, and the two things in an old Portland attic that stop a job before it starts. Of the 64 jurisdictions on this site, 50 publish an energy code edition and 50 a required attic R-value. Every claim below names its source.
The state's code office says that as of April 7, 2025 the code moved from the 2015 editions to the 2021 editions of the International Codes, the 2021 International Energy Conservation Code among them, and that it applies to all new construction and renovations of houses and commercial buildings in Maine. Its residential chapter adopts chapters 1 through 11 of the 2021 International Residential Code, so the IRC's energy chapter is in force with it. A town of more than 4,000 people must enforce the code; a smaller town may choose to, but may not use any other building code.
The state's code office says the code applies to all buildings constructed or renovated in Maine regardless of the town's population, and its FAQ lists renovations of homes alongside new construction. Meeting it is the building owner's responsibility even where the town does not enforce it. Efficiency Maine adds the history: no Maine house built before June 2010 was held to any state energy code, so the age of a house says little about what is in its walls.
| Part of the house | Maine code, climate zone 6 |
|---|---|
| Ceiling or attic | R-60 |
| Wood-frame walls | R-30, or R-20 plus R-10 continuous, or R-13 plus R-15 continuous, or R-20 continuous |
| Floor over unheated space | R-30 |
| Basement walls | R-15 continuous, or R-19 in the cavity, or R-13 plus R-5 continuous |
| Crawl space walls | R-15 continuous, or R-19 in the cavity, or R-13 plus R-5 continuous |
| Slab edge | R-10 continuous, 4 feet deep |
Those are the 2021 IECC's figures for zone 6, except the wall row, which Maine rewrote for zones 6 to 8 (08-003 C.M.R. chapter 7). Maine's chapter also tightens the air-leakage test a new house must pass, from the IECC's 5.0 to 3.0 air changes an hour at the test pressure (and from 0.28 to 0.20 cubic feet per minute per square foot of the enclosure), adds a dew-point check where exterior wall insulation is thinner than R-10, and asks for an air-sealed wall and door where a basement bulkhead comes in.
Every Maine jurisdiction on this site answers to the Maine Uniform Building and Energy Code (2021 IECC with Maine amendments): R-60 for the attic and R-30, or R-20 plus R-10 continuous, or R-13 plus R-15 continuous, or R-20 continuous for walls in new work, climate zone 6.
Code minimums are written for new construction. In climate zone 6 the 2021 IECC's attic figure, R-60, is the same number ENERGY STAR recommends for an attic with nothing in it, so a new house here starts where that recommendation ends. What the table below adds is the house already standing: what to aim for when something is up there already, under the floor, and in walls that only open up when the siding comes off.
| Where | DOE recommendation, zone 6 | Note |
|---|---|---|
| Attic, uninsulated | R60 | The depth that reaches it depends on the material, which is why we mark it on a ruler rather than quote inches |
| Attic with 3–4 inches already there | R49 | The common case in an older house here: something is up there, just not enough |
| Floor over a crawl space | R30 | Only if the crawl space is vented and stays that way |
| Wood frame wall, uninsulated | Blow the empty cavity, plus R5 to R10 sheathing when the siding comes off | New construction figures; a dense-pack retrofit is judged on what fits the cavity |
| Wall already insulated, 2x4 | Add R10 sheathing when the siding comes off | Continuous exterior board, which is a siding job, not an insulation-only one |
These are ENERGY STAR's recommendations for retrofitting existing wood-framed houses in zone 6, which it bases on the 2021 IECC table. All three counties on this site are in IECC climate zone 6A, cold.
The code sets the number. These are the layers that deliver it, numbered from the top.
| Figure | Number | What it drives |
|---|---|---|
| Climate zone | Zone 6A, cold | Every R-value in the state code's table, in all three counties |
| Heating degree days | 6,795 | How hard the furnace works. Base 65°F, 1991–2020 normals at Portland International Jetport |
| Cooling degree days | 447 | Why an under-insulated attic costs you in July as well as January |
| Nights at or below freezing | 144.1 | Condensation on the cold side of the insulation |
| Days that never rise above freezing | 40.7 | Snow stays put on the roof; heat leaking into the attic melts it from below (Efficiency Maine) |
Those are NOAA's figures, printed as published. The heating degree days say how long the furnace, boiler or heat pump runs; the freezing nights say how often snow sits on a roof over an attic that may be leaking heat into it. Efficiency Maine's answer to the ice dams that follow is not a roofer but the attic: seal its air leaks and add insulation.
Every Maine home has the same program to ask about, because Efficiency Maine pays the insulation and air sealing rebates statewide rather than through the electric company. Its table applies to upgrades completed on or after October 1, 2026, and it says its incentives are subject to change or termination, so the amounts below are its published figures, not a promise.
| Insulation, per zone | Low income | Moderate income | Any income |
|---|---|---|---|
| Attic, wall or basement zone, 250–499 sq ft insulated | $2,000 | $1,500 | $1,000 |
| Attic, wall or basement zone, 500 sq ft or more | $4,000 | $3,000 | $2,000 |
| Mobile home underbelly, 500 sq ft or more | $5,000 | $4,000 | $3,000 |
| Air sealing, per zone | Low income | Moderate income | Any income |
|---|---|---|---|
| All accessible attic air leaks sealed | $300 | $225 | $150 |
| All accessible basement or underbelly air leaks sealed | $200 | $150 | $100 |
| Air sealing in the living space, doors and windows included | $100 | $75 | $50 |
Efficiency Maine also offers home energy loans for insulation and air sealing, installed by the same registered vendors; a project does not need a rebate to qualify, and the current terms are on its loan page.
If the plan is to heat the house with heat pumps afterward, that is a separate Efficiency Maine program: for a home that will use heat pumps as its main heat, $9,000, $6,000 or $3,000 for a ducted whole-home system by income tier, or $3,000, $2,000 or $1,000 per eligible outdoor unit for other whole-home systems, plus a $500 bonus per home on eligible upgrades completed and claimed from March 1 through December 31, 2026. We insulate and air seal; we do not install heat pumps.
If the household income qualifies, the work can be free rather than discounted, through the Weatherization Assistance Program that MaineHousing funds. It is run county by county:
That is a different queue from a paid job, and worth checking before anyone quotes you.
EPA describes vermiculite insulation as "a pebble-like, pour-in product" that is "usually gray-brown or silver-gold in color." EPA says a mine near Libby, Montana "was the source of over 70 percent of all vermiculite sold in the United States from 1919 to 1990" and that "the vermiculite from Libby was contaminated with asbestos."
Maine's own rule is stricter than the federal one. The federal asbestos rule leaves out houses of four or fewer units, but the Maine Department of Environmental Protection says that once asbestos-containing material of more than 3 square or linear feet is going to be disturbed, it has to be removed or repaired by professionals unless its regulations specifically exempt it. The homeowner exemption its asbestos page names is an owner-occupied single-family home's own asbestos siding, not attic insulation. So ask the DEP's asbestos program before anyone touches vermiculite. Nothing new gets blown on top of it, and taking it out is a job for an abatement contractor, not for us.
It reads like an insulation rule and is an electrical one, which is why an electrician settles it before the insulation crew is booked. In a house built before the war it is worth checking before you take any quote seriously.
Of the 64 towns and cities on this site, only six publish a rule that reaches an insulation job. New Gloucester lists insulation as maintenance with no permit fee, Bridgton lets it go ahead without a permit inside a building's existing footprint, and Baldwin needs no permit for improvements with no structural change under $25,000. Wells goes the other way: its permit guide names insulation among the work that needs one. Phippsburg and Kittery set dollar lines instead, a permit for most work over $1,000 and $2,000.
Everywhere else, the honest answer is that the city publishes no answer. We confirm it with the department before starting and pull whatever is required. Your city's page says exactly what that city publishes and nothing more.
Maine does not license insulation contractors, or home contractors of any kind. The Attorney General's office says general contractors and the building trades are not licensed or regulated in Maine, and the notice it requires on every home construction contract over $3,000 is headed “Contractors Are Not Licensed.” What the law gives you instead is the contract: insulation or air sealing worth more than $3,000 is home construction work, so it needs a written contract signed by both sides, with start and completion dates, the total price, no more than one-third down, the statutory warranty and a written change-order rule (10 M.R.S. §§ 1486–1490). If you sign at home after a visit or call you did not ask for, you can cancel in writing within three business days, and work that becomes part of the house may not start until that time has passed (32 M.R.S. §§ 4663–4664-A). The Attorney General's Consumer Protection Division (1-800-436-2131) can tell you whether a contractor has drawn consumer complaints.
What matters more for the rebate is Efficiency Maine's own list. It pays only on work by a Residential Registered Vendor, and it says its registered vendors are certified by the Building Performance Institute. Its vendor locator shows who is on the list.
The code and the rebates decide the target; how the work is done is on each service page: attic insulation, spray foam insulation, crawl space insulation, basement insulation, garage insulation, insulation removal, home energy assessment, wall insulation and air sealing.
Municipal research 2026-10-24; energy code, rebate and climate research 2026-10-24. Rebate amounts carry the program year they were published under. Sources: maine.gov (2) · efficiencymaine.com (2, 3, 4) · irs.gov (2) · energystar.gov · ncei.noaa.gov · epa.gov · berkeleyca.gov. These change; confirm with the office or the utility first.
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