Mass Save insulation rebates in 2026: 75% off, no-cost options and the steps for Somerville, Cambridge and Greater Boston
Mass Save insulation in 2026: how the 75% rebate and no-cost income-eligible offer work, what's covered, the federal credit that ended, and the steps to get started.
Mateus MagnoLicensed Construction Supervisor · October 22, 2026 · 3 min read
In 2026 most Massachusetts homeowners can get 75% off approved insulation and air sealing through Mass Save, and income-eligible households can get it at no cost. Everything starts with a no-cost Home Energy Assessment. The federal 25C tax credit for insulation ended for work placed in service after December 31, 2025, so Mass Save is now the main way to cut the cost.
If you live in Somerville, Cambridge or anywhere in Greater Boston and you're thinking about insulation, check Mass Save before you do anything else. It is the energy-efficiency program funded through your electric and gas bills, run by the utilities (Eversource, National Grid, Unitil and Cape Light Compact). For insulation, it's the biggest discount available in 2026.
What Mass Save offers for insulation in 2026
- 75% off approved insulation and air sealing for most residential customers. The discount is usually taken right off the contractor's invoice.
- No-cost insulation for income-eligible households. Thresholds depend on household size and change over time, so check the Mass Save income-based offers page.
- Air sealing is part of the package and is often the most valuable piece.
- 0% HEAT Loan financing for qualifying energy upgrades, to spread out what's left.
Rebate details can change during the year. Always confirm current numbers on masssave.com before you sign anything.
The federal insulation tax credit ended
For several years you could also claim the federal Energy Efficient Home Improvement Credit (25C), worth up to $1,200 a year for insulation and air sealing. That credit is not available for work placed in service after December 31, 2025, according to the IRS. If your insulation was finished in 2025, you may still claim it on your 2025 return. For 2026 projects, Mass Save is the main help.
Step by step: how to get Mass Save insulation
- Book a no-cost Home Energy Assessment on the Mass Save website or by phone. An energy specialist visits (or does a virtual visit), looks at your attic, walls and basement, and often runs a blower-door test to measure air leaks.
- Get your recommendations. The specialist lists approved insulation and air sealing and what the program will pay.
- Clear any "barriers." If they find knob-and-tube wiring, vermiculite, mold or a bath fan venting into the attic, it must be fixed before insulation. Read my guide to these attic barriers.
- Schedule the install with a program-approved insulation contractor. Your share (usually 25%) is billed after the discount.
- Final check. The work may be inspected to make sure it meets program standards.
What Mass Save usually covers, and what it doesn't
| Usually covered | Usually not covered (or limited) |
|---|---|
| Attic floor insulation and air sealing | Insulation that is purely part of a remodel you're already doing |
| Dense-pack wall insulation in existing homes | Fixing roof leaks, rot or structural problems |
| Basement and rim joist insulation (when recommended) | Removing and replacing finished walls or ceilings |
| Weatherstripping and sealing attic hatches | Cosmetic patching beyond basic hole repair |
This is where a general contractor helps. I can handle the work around the insulation: opening and closing walls, rebuilding an attic hatch, fixing rot, or coordinating the electrician before the insulation crew arrives.
Should you skip Mass Save and pay full price?
Sometimes it makes sense, for example in a full gut renovation, an addition, or new construction where the code sets the insulation. Then the insulation is part of the building permit and gets inspected with the job. Somerville and Cambridge, like most of Greater Boston, follow the state's stretch energy code (or the stricter specialized code), which sets high insulation levels for new work. See how much attic insulation you need.
For an existing house that just needs more insulation, start with Mass Save. Then compare. For context, see what 2,089 real insulation jobs cost in Greater Boston, and for other local programs see Somerville home rebates and loans.
Need help around your insulation project?
Magno & Co installs insulation in Somerville, Cambridge and across Greater Boston. We also handle the carpentry, wall openings and repairs that come with it. Book a free walkthrough and I'll tell you honestly whether Mass Save is your best first step.
Frequently asked questions
How much does Mass Save pay for insulation in 2026?
Most Massachusetts homeowners can get 75% off approved insulation and air sealing through Mass Save in 2026. Income-eligible households can get recommended insulation at no cost. Confirm current amounts on masssave.com.
Is there still a federal tax credit for insulation in 2026?
No. The federal 25C Energy Efficient Home Improvement Credit does not apply to work placed in service after December 31, 2025. Work finished in 2025 may still be claimed on a 2025 return.
Do I need a Home Energy Assessment to get Mass Save insulation?
Yes. Mass Save insulation incentives start with a no-cost Home Energy Assessment. An energy specialist checks your home and lists the approved insulation and air sealing.
Can Mass Save insulate over knob-and-tube wiring?
Not until it's dealt with. Knob-and-tube wiring, vermiculite, mold and bath fans venting into the attic are treated as barriers that must be fixed before insulation is installed.
Mateus Magno is the founder of Magno & Co — a licensed Massachusetts Construction Supervisor (CS-123658), registered Home Improvement Contractor (HIC #220484) and certified Lead-Safe Renovator Supervisor who has renovated and managed over $3 million in projects across Greater Boston.
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