Mass Save Insulation Rebate in Massachusetts: 75–100% Covered (2026)

The Mass Save insulation rebate in Massachusetts covers 75 to 100 percent of the cost of approved insulation and air sealing, with income-eligible households paying nothing at all. That is the headline, and it is real, but two things decide whether it applies to you: whether your home is served by one of the six Mass Save sponsors (around 40 municipal-light-plant towns are not), and whether you go through the program's free Home Energy Assessment or an approved Direct Install contractor. This guide is the money-and-eligibility explainer. We cover what gets paid, who qualifies, and the catches that the contractor blogs ranking for this query leave out.

One correction up front, because it matters for 2026 work: the federal 25C tax credit that used to stack on top of this expired December 31, 2025. Do not budget around it. More on that below.

Does Mass Save pay for insulation? Yes, 75 to 100 percent

Mass Save pays for 75 to 100 percent of approved insulation and air sealing improvements on eligible Massachusetts homes. Targeted air sealing is included at no cost as part of the Home Energy Assessment. The exact percentage depends on your household income tier, but every qualifying customer gets at least 75 percent off, and income-eligible residents get the work done at no cost.

A few definitions, because "Mass Save" gets used loosely:

• Mass Save is the brand for the energy-efficiency programs run by Massachusetts's utility sponsors, overseen at the state level by the Department of Energy Resources (DOER). It is not a government agency and not a single company, it is six sponsors operating a shared program.
• The six Mass Save sponsors are Berkshire Gas, Cape Light Compact, Eversource, Liberty, National Grid, and Unitil. If your electric or gas bill comes from one of these, you are a Mass Save customer.
• Insulation and air sealing here means the standard residential weatherization measures: attic, wall, and basement/crawlspace insulation, plus sealing the air leaks that make an old Massachusetts house drafty.

So when a contractor's site shouts "Mass Save covers 100% of insulation," that is true for some households and overstated for others. The honest version is 75 to 100 percent, and the percentage is set by your income, not by the contractor.

How the 75–100% coverage actually works

The percentage you get is tiered by household income. Mass Save runs a standard tier and income-based enhanced tiers, with the lowest-income households reaching no-cost work.

Tier	Who it's for	What you pay for insulation/air sealing
Standard	Most homeowners and renters	25% of approved cost (Mass Save covers 75%)
Income-eligible / enhanced	Households under the program's income thresholds	$0, no-cost insulation and air sealing

There is no published flat dollar cap on the standard insulation incentive on the Mass Save insulation page, it is a percentage, not a fixed "$2,000" number, despite what several contractor blogs claim. Your installer prices the job, and you pay your 25 percent share of the approved scope. For what that 25 percent realistically comes to on a typical attic job, see attic insulation cost in Massachusetts, we don't re-derive cost-per-square-foot here.

The income thresholds for the enhanced and income-eligible tiers move with household size and the program year, and the exact Area Median Income cutoffs are best read off the live income-eligible page rather than memorized, figures floated by third-party sites for a household of four have ranged widely. Treat "around 60 percent of Area Median Income" as the rough line for the income-eligible (no-cost) tier and confirm your number on masssave.com when you book.

The free Home Energy Assessment is the gateway

The Mass Save Home Energy Assessment is the free, no-obligation home visit that opens the door to the insulation rebate, and it is the recommended path to the 75–100% incentive. An Energy Specialist walks the house, models the heat loss, does the no-cost air sealing on the spot where possible, and writes up the insulation scope that the rebate then applies to.

You do not always have to take the assessment route, Mass Save also lets you work through a Direct Weatherization Independent Installation Contractor, which can skip the standalone assessment. But for most homeowners the assessment is the cleaner gateway, and it is genuinely free.

We keep the step-by-step of the visit itself, what the specialist does, the combustion-safety check that can stall things, how to book, in the dedicated Mass Save Home Energy Assessment guide. Start there for the process; come back here for the dollars.

The 0% HEAT Loan finances the part rebates don't cover

The Mass Save HEAT Loan is a 0% interest loan of up to $25,000 that finances the homeowner's share of weatherization and other approved energy work. The sponsors buy down the rate, so you genuinely pay no interest, the loan covers the 25 percent of insulation you owe, plus a long list of other measures.

Eligible measures under the HEAT Loan include:

• Weatherization (insulation and air sealing)
• Pre-weatherization barrier remediation (knob-and-tube, vermiculite, see below)
• ENERGY STAR windows
• Heat-pump projects and heat pump water heaters
• Residential batteries (ConnectedSolutions)

To qualify for the HEAT Loan you need a current residential electric or gas account with one of the six sponsors, Berkshire Gas, Cape Light Compact, Eversource, Liberty, National Grid, or Unitil. There is a useful carve-in for municipal-electric customers: if your town runs its own electric utility but your home heats with natural gas from a Mass Save sponsor, you qualify on the gas side.

The loan term and the participating lenders aren't fixed on the financing page, so ask your participating lender for the current term when you apply rather than trusting a number off a contractor's blog. Heat pumps are HEAT-Loan-eligible too, but the rebate amounts for those are a separate topic, see heat pump rebates in Massachusetts for 2026.

Who qualifies, homeowners, renters, landlords, condos

Eligibility for the Mass Save insulation rebate comes down to two questions: is your home served by a Mass Save sponsor, and which income tier are you in. The program is broader than most people assume, it is not homeowners-only.

• Homeowners in 1–4-unit buildings get the standard 75 percent (or no-cost if income-eligible).
• Renters can book a Home Energy Assessment and access weatherization without going through the landlord first. You do not need to own the home to start the process.
• Landlords of 1–4-unit properties can reach up to 100 percent off insulation, which is the part most owners of small rental buildings never hear about.
• Condos are eligible; the path depends on whether the work is inside your unit or in common areas governed by the association.
• Income-eligible households (roughly under 60 percent of Area Median Income, confirmed by household size) get no-cost insulation and air sealing.

The single biggest disqualifier is not income. It is your town.

Why ~40 towns are excluded: the Municipal Light Plant problem

Around 40 Massachusetts towns are not eligible for Mass Save because they are served by a Municipal Light Plant (MLP), a town-owned electric utility, rather than by one of the six Mass Save sponsors. Mass Save is funded through a charge on the bills of its sponsors' customers, so if you don't pay one of those sponsors, you are not in the program. MLP towns run their own, usually thinner, weatherization rebates instead.

	Mass Save sponsors	Municipal Light Plant (MLP) towns
Examples	Eversource, National Grid, Unitil, Berkshire Gas, Liberty, Cape Light Compact	~40 towns including Concord, Wellesley, Belmont, Reading, Norwood, Holyoke
Insulation incentive	75–100% off via Mass Save	Town program, typically smaller (e.g., Concord/CMLP: 50% up to $1,000 / 75% up to $1,500 / 100% up to $2,000, by income)
Who runs it	Six utility sponsors + DOER oversight	Your town's light department

There is one important nuance the competitors miss. If you live in an MLP town but heat with natural gas supplied by a Mass Save sponsor, you are routed back to Mass Save for the gas side of your home. So a Concord home on Eversource gas, for example, contacts Mass Save for gas-heating weatherization even though its electricity comes from the municipal light plant.

If your town is on the MLP list, start with your municipal light department's program, and read our MLP towns and Mass Save breakdown for the full routing and the gas carve-in.

Pre-weatherization barriers that can stall the job

Two old-house conditions common in Massachusetts can block insulation until they're fixed: knob-and-tube wiring and vermiculite or asbestos. Mass Save calls these pre-weatherization barriers, and they have their own incentives and caps.

Barrier	Why it blocks insulation	Mass Save incentive	Cap
Knob-and-tube wiring	Old wiring can overheat under insulation; must be remediated first	$3/sq ft	Up to 50% of rewiring cost
Vermiculite / asbestos	Must be safely abated before insulating	$1/sq ft	$4,000 per measure (building under 8,000 sq ft)

The overall barrier-mitigation project incentive caps at $16,000 for a building under 8,000 square feet. Both barriers are common in the older housing stock around Greater Boston and the Pioneer Valley, and finding one mid-project is the most frequent reason an insulation job stalls in Massachusetts.

We keep the remediation specifics elsewhere: see insulating around knob-and-tube wiring and vermiculite and asbestos attic insulation. The rule to remember here is that the barrier has to clear before the insulation incentive applies, and the HEAT Loan can finance the remediation.

The federal 25C credit, what changed for 2026

The federal Energy Efficient Home Improvement Credit (IRS 25C), the 30 percent, up-to-$1,200-a-year credit homeowners used to stack on insulation, expired for property placed in service after December 31, 2025. For insulation work done in 2026, there is no federal 25C credit to claim.

This is the single most out-of-date thing on the pages currently ranking for this query. The 25C credit applied to qualifying insulation and air sealing placed in service on or after January 1, 2023 and before December 31, 2025. If your insulation was installed and completed in 2025, talk to your tax preparer about claiming it on your 2025 return. If the work happens in 2026, plan around the Mass Save incentive and the HEAT Loan alone, the federal piece is gone.

That makes the Mass Save 75–100% coverage more important than ever, since it is now the main money on the table for Massachusetts insulation rather than one of two stacked programs.

What to actually do

1. Check whether you're a Mass Save sponsor customer or in an MLP town, look at who bills you for electricity, and check your gas supplier separately.
2. If you're a sponsor customer, book the free Home Energy Assessment, it's the gateway to the 75–100% insulation incentive.
3. If you're in an MLP town, start with your town's light department program, unless you heat with sponsor-supplied gas, in which case contact Mass Save for the gas side.
4. Plan the project around the Mass Save incentive and the 0% HEAT Loan for your share, not the expired federal credit.
5. Browse all insulation guides and contractors to line up the work.

FAQ

Does Mass Save really pay 75 to 100 percent for insulation? Yes. Approved insulation and air sealing is 75–100 percent covered for eligible Massachusetts homes, and income-eligible households pay nothing. The percentage is set by your income tier, not negotiated with the contractor.

Is there a dollar cap on the Mass Save insulation rebate? The standard insulation incentive is a percentage (75 percent covered, you pay 25 percent), with no published flat dollar cap on the Mass Save insulation page. Pre-weatherization barriers like knob-and-tube and vermiculite have their own caps, and the barrier-mitigation project total caps at $16,000 for buildings under 8,000 square feet.

Do I have to get the free Home Energy Assessment first? It's the recommended gateway and the cleanest route to the incentive, but not strictly required, Mass Save also lets you work through a Direct Weatherization Independent Installation Contractor and skip the standalone assessment.

What is the 0% HEAT Loan and how much can I borrow? The HEAT Loan is a 0 percent interest Mass Save loan of up to $25,000 that finances your share of insulation plus other approved measures like windows, heat pumps, and barrier remediation. The sponsors buy down the interest. Ask the participating lender for the current term.

Why isn't my town eligible for Mass Save? Around 40 Massachusetts towns are served by a Municipal Light Plant rather than a Mass Save sponsor, so they aren't in the program and run their own town weatherization rebates. If you heat with natural gas from a Mass Save sponsor, you're still routed to Mass Save for the gas side.

Can I still claim the federal tax credit for insulation in 2026? No. The federal 25C Energy Efficient Home Improvement Credit expired for property placed in service after December 31, 2025. For 2026 insulation work, the Mass Save incentive and HEAT Loan are the available programs.

Can renters and landlords get the insulation rebate? Yes. Renters can book a Home Energy Assessment without the landlord, and landlords of 1–4-unit properties can reach up to 100 percent off insulation.