What insulation rebates pay in Somerville
We re-read MassCEC's weatherization page on October 3, 2026. Mass Save's own site blocks our checks, so its assessment page comes from a July 3, 2026 snapshot. These are statewide Mass Save offers for Mass Save utility customers.
Home Energy Assessment
In person or virtual. It is the door to every Mass Save insulation offer.
Insulation and air sealing
The standard Mass Save discount on insulation, air sealing and weather stripping.
Income-qualified or whole 1-4 unit building
For households that qualify by income, or a 1-4 unit building where all the owners agree to weatherize together.
Single-pane to triple-pane windows
Listed with the weatherization offers on MassCEC's page.
Mass Save HEAT Loan
Terms up to 7 years, for your share of the cost.
Energy Saver Home Loan
At up to 2% for up to 20 years, for income-qualified households.
Working it out
MassCEC's example for a 2,000 square foot home: $4,000 of insulation and air sealing before incentives, $1,000 after the 75% Mass Save discount. If the household qualifies by income, or the home is in a 1-4 unit building where every owner joins in, the cost can drop to zero. The 0% HEAT Loan can spread the rest over up to 7 years.
Somerville housing
The US Census Bureau's survey (2020 to 2024) counts 37,756 homes in Somerville. About 55% are in buildings with two to four units, and 59% were built before 1940. Both are the highest shares on our list. Only 11% are single-family detached, and 66% of households rent.
Weatherize the whole building
MassCEC says the cost can drop sharply when a 1-4 unit building is weatherized as one project with every owner agreeing. In a Somerville two- or three-family split into condos, start by sharing this with the other owners. One assessment for the building, one contractor and one project usually beats each owner doing their own unit.
Renters can book the free assessment too. The owner approves the work.
How the Mass Save insulation offer works
You don't apply for an insulation rebate on your own. You book a free Home Energy Assessment with Mass Save, by phone at 866-527-7283 or online. An energy specialist looks at your attic, walls and basement, and recommends work. If you go ahead, a Mass Save contractor does it, and the discount comes off the bill. You don't pay full price and wait for a cheque.
Renters and landlords can book an assessment too. A renter can get the visit, but the owner signs off on insulation. Mass Save also has a separate track for buildings with five or more units.
How to get insulation rebates in Somerville
- Book a free Mass Save Home Energy Assessment online or at 866-527-7283.
- If you might qualify by income, say so when you book. It can raise the discount to 100%.
- If you own a unit in a 1-4 unit building, ask the other owners to join. Doing the whole building together can also reach 100%.
- Let the energy specialist recommend the work, then pick a Mass Save contractor.
- Pay your share after the discount, or use the 0% HEAT Loan.
Common questions
How much does Mass Save pay for insulation in Somerville?
75% off insulation, air sealing and weather stripping as standard. Up to 100% for income-qualified households or 1-4 unit buildings where all owners agree to one project.
Do all owners in my Somerville building have to agree?
For the whole-building discount, yes. MassCEC says the lower cost applies when all owners of a 1-4 unit building agree to weatherize as part of the same project.
Is the Mass Save home energy assessment really free?
Yes. Mass Save offers a no-cost assessment in person or by video, plus a no-cost online assessment.
Can renters get Mass Save insulation?
Renters can book the free assessment. The building owner has to agree to any insulation work.
Does Mass Save help with windows?
Only in one case on MassCEC's list: $75 per window for replacing single-pane windows with triple-pane windows. Insulation and air sealing get the larger discount.
What to do next
Book the free assessment first. Then read about Somerville heat pump rebates, since insulation unlocks the whole-home rate, or see the full list of Mass Save rebates.
By Sam Menard. Sources, last read October 3, 2026: MassCEC: Weatherization (Mass Save discounts and loans), Mass Save: Home Energy Assessments (snapshot July 3, 2026), MassCEC: Air-source heat pumps (loan terms), US Census Bureau ACS 5-year 2020-2024, table B25034 (year built). All Somerville rebates → Every Mass Save rebate →