Mass Save Heat Pump Rebates, Read Slowly

The form runs to two pages, and it tends to sit on the kitchen table longer than anyone plans. In an older house it usually turns up in the same season as everything else: the boiler has started to complain, the oil bill has landed, and an estimate has come in with a line near the bottom showing a rebate already subtracted. That line looks settled. It isn’t settled until the paperwork has been accepted, and the paperwork assumes a tidier house than most of the ones in Worcester County.

A house from the 1920s fails the first weatherization test by birth date. It may keep radiators in the back bedrooms because nobody can find a good place for an indoor unit. It may have two apartments on one meter, a boiler that also makes the hot water, or a chimney that complicates what happens when that boiler leaves. None of this rules out a rebate, but each of those facts pushes the house toward one rebate and away from another.

So here is the 2026 Mass Save rebate form, taken one clause at a time. Everything below is as published for 2026, and the form itself warns that the program can change without notice. Our advice is simple. Work out which rebate your house can honestly meet, then look at the calendar, in that order.

How much is the Mass Save heat pump rebate in 2026?

For a house that meets the conditions, the whole-home rebate is $2,650 a ton, capped at $8,500, and the partial-home rebate is $1,125 a ton, capped at $8,500. Those two figures come straight from the form. A third offer, the basic rebate, was reported by Green Newton in January 2026 at $250 per ton up to $2,500. It has its own separate form, and the main form sends you there if you aren’t displacing fossil fuel or electric resistance heat.

A ton here is a unit of capacity, not weight: 12,000 BTU. One small detail is easy to miss. The form’s equipment table asks for the AHRI-certified cooling capacity in BTUs next to the number of tons, so the rebate arithmetic starts from the certified rating of the machine and not from a round number on an estimate. Ask the installer to show you that figure before you trust a rebate line.

The sums below use example sizes to show how the per-ton rate and the cap interact. They aren’t sizing advice, and they aren’t what your house needs. A proper load calculation decides that.

Divide the cap by the rate and you find where the ceiling sits: about 3.2 tons on a whole-home job in either year. Past that point, more capacity brings in no more money. On partial-home the cap is far away, at roughly 7.5 tons. The rebate also can’t exceed the installed cost of the job.

Income-based customers have a different ladder. Enhanced rebates reach up to $16,000 for air source equipment. Weatherization recommended by the assessment has to come first, and it’s free for income-verified customers. An Installer Network contractor is still required, and electric panel or health and safety work that has to precede weatherization can be paid for at up to 100 percent. We couldn’t confirm the income thresholds, so check them with the program before ruling yourself in or out.

Two neighbors of this rebate are worth a look if your plans differ. Air-to-water systems carry the same $2,650 a ton, capped at $8,500, the same enhanced ceiling and the same 2027 drop. A heat pump water heater has its own $750 per unit offer for 1-4 unit buildings, with an ENERGY STAR unit at UEF 3.30 or higher, installed in calendar 2026 and with the form in by Feb. 28, 2027.

Whole-home or partial-home: which rebate can an older house meet?

Most older houses that keep any fuel in use belong on partial-home, and those ready to give up fuel entirely can reach for whole-home. The whole-home offer asks for the heat pump to handle all heating and cooling on its own, a house that counts as sufficiently weatherized, and a signed verification form.

Partial-home is built around the boiler you keep. Where a fuel system stays on for some zones, the job needs an integrated control from Mass Save’s own qualified list, a device that decides when the heat pump runs and when the old system takes over. It must be set at or below the program’s maximum switchover temperature. The form has a blank for that setting, and we couldn’t confirm the number, so ask to see it. Skip the control and the old heating must come out, or be disabled, wherever the heat pumps now serve, with that disconnection shown on the invoice. Read the invoice for that line before you pay it, since it’s far easier to add then than after the claim goes in.

Partial-home also has two bonuses. A $500 weatherization bonus goes to customers who weatherized through Mass Save before the install or up to six months after it. A $500 sizing bonus goes to equipment sized to 90-120 percent of the total heating load at the outdoor design temperature, per ACCA Manual J, throughout 100 percent of the conditioned space, with Manual J, S or D paperwork attached. Notice what that second one means. You’d size the system as though it could carry the whole house, and still get paid at the partial rate. The form also says rebates may not exceed $8,500, so a job near the top should ask how the bonuses count.

Now the honest comparison, again on an example size. At 3 tons, the whole-home sum is $7,950, against $3,375 on the partial-home rate, or $4,375 if both bonuses land. So whole-home pays $3,575 to $4,575 more on that example, and that gap is what you are weighing against giving up your last fuel-burning backup. It’s a real sum, though it shouldn’t decide alone. A house on steam, or one whose back rooms can’t get an indoor unit, may not be able to take it. We’ve set out the backup question in our story on keeping the oil boiler, and the plumbing side in the piece on radiators.

If you heat with gas, check the form for your fuel. Published program descriptions don’t all agree on how gas fits the whole-home offer, while the form plainly has a line for natural gas customers and routes those conversions through the gas sponsor.

What does "sufficiently weatherized" mean for the whole-home rebate?

It means meeting at least one of three tests, and for an older house only two remain open. The form lists them in a footnote: the home was built during or after 2000; a Home Energy Assessment report shows less than $1,000 of weatherization recommended; or weatherization recommendations made during or after 2013 have been completed.

That sends nearly every reader of this magazine to the same place, which is an assessment. If you had one in 2013 or later and did what it said, you may already pass, provided you can show it. Otherwise the assessment comes first and the work it recommends comes next. The form has a field for the Assessment Site ID, which is a good sign of how central this step is. We lay out the order of those steps, and how the 0 percent loan fits around them, in the story on the assessment and the HEAT Loan.

Why does the installation date matter so much?

Because two sets of rates are in play, and the install date picks between them. The form covers equipment purchased and installed between Jan. 1, 2026 and Dec. 31, 2026. For installs on or after Jan. 1, 2027, the whole-home rate becomes $2,350 a ton with a $7,500 ceiling, and the partial-home rate becomes $1,000 a ton with the same ceiling. As this issue goes up in November 2026, about eight weeks of the year remain.

Then the paper deadline runs on. Your form and documents must be received by Feb. 28, 2027. The terms on the second page say postmarked by that date, while the front says received. Plan to the tighter word. Allow 6-8 weeks for payment once the form is processed and approved, and longer if something is missing. Since Oct. 1, 2026, serial numbers are also required on heat pump rebate applications, so have the installer record them on the day, before the outdoor unit is under a snowbank.

How hard should the date push you? Look back at the table. On a 3-ton whole-home example, slipping into January costs $900. We’d take that hit before we’d accept a skipped load calculation or a boiler removal in a cold snap with no plan. A rebate is a one-time payment, while a badly designed system is what you live with every winter afterward.

A rebate is a one-time payment, while a badly designed system is what you live with every winter afterward.

What can quietly disqualify a heat pump rebate claim?

Usually a small condition nobody checked before signing. The ones that matter most in an older house are these. The installer must belong to the Mass Save Heat Pump Installer Network, and the equipment must be on the Qualified Product List, so check both by name and model number. The offer is not for new construction or major renovation, which matters if the heat pump is one line in a gut job; our stretch code story covers how that kind of project is treated by the building department, and you should ask the program how it would treat yours. The home has to be occupied full time during the winter heating season, so a summer place with a cold January doesn’t qualify.

There’s one whole-home rebate per customer account. The offer may not be combined with another utility or efficiency provider’s offer on the same equipment, except the HEAT Loan. And the invoice has its own checklist: installer name and address, outdoor and indoor model numbers, any integrated control models, install date and address, total install cost for each system, and proof of payment. Projects are chosen at random for inspection, and refusing one can forfeit the money.

How do Mass Save rebates work in a two-family or a triple-decker?

They follow the meters. In buildings of 1-4 units, if each unit has its own gas account (for gas conversions) or electric account (for oil, propane or resistance conversions), each unit is eligible. If one meter serves every unit, the building gets one rebate. So a three-decker on three electric meters and a three-decker on one are different propositions, whatever the buildings look like from the street.

The form also asks whether the property is owner or renter occupied and how many units the system serves. An owner footing the bill can take the rebate directly on individually metered rentals whose account sits in the tenant’s name, as long as the tenant gives permission. Customers in buildings of five or more units can get the whole-home rebate if the verification requirements are met, with weatherization encouraged but not required. Who gets to make these choices is often the owner or the condo association and not the person who lives on that floor; our triple-decker story on who decides starts there, and the one on converting floor by floor takes up the sequence.

Most older houses should start with the assessment, then choose between whole-home and partial-home on how the house actually heats. The money follows that choice, and the date only sets the rate.