Heat Pump Adoption by Town: Massachusetts Permit Data
By the permits.llc team · Last reviewed September 25, 2026 · Optimal window: Weeks 1–4 after a heat-pump record files; before November 1 for the seasonal-rate conversation
TL;DR
- Across 25 Massachusetts towns, heat pumps were 36% of heating permit records, with boilers and furnaces the rest.
- Otis, Mattapoisett and Somerville led at about one heat pump per boiler; Taunton trailed at one per five.
- In 2026 Somerville's share fell from 56% to 45% while Easthampton rose from 28% to 60%.
- The seasonal heat pump electric rate restarts November 1; households that installed without a rebate must self-enroll.
Heat pump adoption in Massachusetts is a town-by-town story, and permit records show it more directly than any rebate total. In our Massachusetts permit file from January 2025 through July 2026, 25 towns carried at least 50 heating records each, and the number of heat-pump records per furnace or boiler record ranged from 1.12 in Otis to 0.19 in Taunton.
The ranking is also moving. Comparing January to July 2025 with January to July 2026, the heat-pump share of heating records rose in 15 of the 25 towns and fell in 10. Somerville, the town most people would name as the electrification leader, fell from 56% to 45%. Easthampton went from 28% to 60%.
A permit is a signal about the homeowner, not the contractor. A heat-pump record says a household chose electric heat this year; a boiler record says it chose to stay with combustion for another 20. The ratio of the two, by town, tells a contractor which conversation to open in which market, and that is what this piece gives you.
What does the heat-pump-to-boiler ratio measure?
It measures, for one town, how many permit records naming a heat pump were filed for every record naming a furnace or boiler over the same months. A ratio of 1.0 means the two ran level. A ratio of 0.25 means four boiler or furnace records for every heat-pump record.
The counting rules are the same ones behind our Massachusetts heating-season boiler permit clock. A heat-pump record is any record whose work description names a heat pump, a mini-split or a ductless unit. A furnace or boiler record is any record whose description names either. Duplicates are out. A record that names both, such as a boiler coming out and a heat pump going in, counts in both columns. The month is the application date where the town publishes one and the decision date where it does not.
We use a ratio rather than raw counts for a simple reason. Falmouth filed 386 heat-pump records in 19 months, more than Melrose's 276, but Falmouth also filed 819 boiler and furnace records against Melrose's 322. Falmouth is the bigger heating market. Melrose is the one converting faster.
Why these 25 towns? They are the Massachusetts towns in our file with at least 50 matched heating records over the 19 months and a full set of trade streams (gas, plumbing, electrical and building permits all publishing). Two towns that passed the threshold, Ashland and Medfield, are left out: their descriptions stopped matching in 2026 (Ashland went from 144 heating matches in January to July 2025 to one in the same months of 2026, Medfield from 143 to zero), which is a change in how the portal publishes, not in what homeowners bought.
The town table: 25 Massachusetts towns ranked
Counts are Massachusetts permit records dated January 1, 2025 through July 31, 2026. "Share" is heat-pump records as a percentage of all heating records. The last column compares January to July 2025 with January to July 2026.
| Town | County | Furnace / boiler | Heat pump | Heat pumps per boiler | Heat-pump share | Share, Jan–Jul 2025 → 2026 |
|---|---|---|---|---|---|---|
| Otis | Berkshire | 25 | 28 | 1.12 | 53% | 62% → 67% |
| Mattapoisett | Plymouth | 74 | 82 | 1.11 | 53% | 53% → 63% |
| Somerville | Middlesex | 593 | 574 | 0.97 | 49% | 56% → 45% |
| Melrose | Middlesex | 322 | 276 | 0.86 | 46% | 50% → 45% |
| Easthampton | Hampshire | 140 | 113 | 0.81 | 45% | 28% → 60% |
| Holliston | Middlesex | 325 | 248 | 0.76 | 43% | 43% → 46% |
| Sherborn | Middlesex | 73 | 55 | 0.75 | 43% | 41% → 52% |
| Holden | Worcester | 255 | 173 | 0.68 | 40% | 39% → 47% |
| Milton | Norfolk | 226 | 151 | 0.67 | 40% | 44% → 43% |
| Belmont | Middlesex | 323 | 198 | 0.61 | 38% | 39% → 38% |
| Hanson | Plymouth | 58 | 34 | 0.59 | 37% | 52% → 38% |
| Concord | Middlesex | 278 | 161 | 0.58 | 37% | 42% → 36% |
| Acushnet | Bristol | 64 | 36 | 0.56 | 36% | 33% → 26% |
| Bellingham | Norfolk | 307 | 151 | 0.49 | 33% | 30% → 47% |
| Falmouth | Barnstable | 819 | 386 | 0.47 | 32% | 32% → 35% |
| Weston | Middlesex | 271 | 123 | 0.45 | 31% | 28% → 39% |
| Randolph | Norfolk | 219 | 96 | 0.44 | 30% | 29% → 42% |
| Lynnfield | Essex | 182 | 78 | 0.43 | 30% | 38% → 26% |
| Billerica | Middlesex | 568 | 227 | 0.40 | 29% | 26% → 32% |
| Braintree | Norfolk | 269 | 100 | 0.37 | 27% | 24% → 27% |
| West Bridgewater | Plymouth | 51 | 16 | 0.31 | 24% | 40% → 16% |
| Hingham | Plymouth | 193 | 56 | 0.29 | 22% | 18% → 43% |
| Rockland | Plymouth | 157 | 45 | 0.29 | 22% | 33% → 17% |
| Pembroke | Plymouth | 142 | 40 | 0.28 | 22% | 21% → 23% |
| Taunton | Bristol | 395 | 75 | 0.19 | 16% | 13% → 21% |
| All 25 | 6,329 | 3,522 | 0.56 | 36% | 36% → 39% |
Two patterns stand out before any caveat. Middlesex County towns cluster in the top half: six of the top 12. Plymouth County splits, with Mattapoisett at the top and Hingham, Rockland and Pembroke near the bottom. County is not the unit that explains this. The town is.
Where did the ratio move in 2026?
Up, on balance, and in places nobody would have predicted from the 2025 numbers. Across the 25 towns the heat-pump share of heating records went from 36% in January to July 2025 to 39% in January to July 2026. That rise happened in the first year the Mass Save whole-home air-source rebate dropped to $2,650 a ton with an $8,500 cap, and the first year units on R-410A refrigerant no longer qualified. We covered those changes in the Mass Save 2026 rebate changes piece. A smaller rebate did not shrink the heat-pump share in this set of towns. It did not grow it fast either.
The towns that moved most:
- Easthampton: 28% to 60%. Heat-pump records went from 19 to 70 while boiler records held at about 50.
- Hingham: 18% to 43%. Boiler records halved (80 to 40) and heat-pump records nearly doubled (17 to 30).
- Bellingham: 30% to 47%, with heat-pump records up from 48 to 69.
- Randolph: 29% to 42%. Weston: 28% to 39%.
- Somerville: 56% to 45%. Heat-pump records fell from 233 to 209 and boiler records rose from 180 to 259.
Somerville is the useful surprise. It still has more heat-pump records than any town in the table, and over the full 19 months it is level with boilers. But its 2026 movement ran the other way from the aggregate. Territory set by reputation would keep pouring heat-pump marketing into Somerville and miss Hingham and Easthampton, where the share is climbing.
Treat the small towns with care. Otis, Hanson, West Bridgewater, Acushnet and Sherborn have 50 or fewer heating records in each seven-month window, so a swing of ten records moves their share by double digits. Their year-over-year column is noise until it repeats.
What the ratio does not tell you
It does not tell you why a town converts. Our file does not carry heating fuel, gas-main availability or household income, and we have not joined a town-level fuel source to it, so we do not claim that Otis leads because it lacks gas or that Taunton trails because it has it. Those may be true. We have not shown them.
Four more limits, stated plainly:
- Description coverage decides who appears. These 25 towns carry about 96% of all the Massachusetts heating matches in our file for the period (3,522 of the 3,641 heat-pump records and 6,329 of the 6,562 furnace or boiler records). Most towns publish work descriptions too terse to match. A missing town is usually a quiet portal, not a quiet market.
- Oil replacements are undercounted. Oil burners are permitted by the local fire department under 527 CMR 1.00, not by the building department, so an oil boiler swap often reaches a building feed only through its electrical or plumbing permit. In an oil-heavy town the boiler column is a floor, which makes the heat-pump ratio look higher than it is.
- Some mini-splits are bought for cooling. A homeowner who adds one for a hot bedroom has not left the boiler. The heat-pump column counts installs, not fuel switches.
- It is one heating cycle. Nineteen months is enough to rank towns and not enough to call a trend. The year-over-year column compares two seven-month windows.
That makes the ratio a targeting signal, not a finding about the energy transition. For an operator, that is enough.
Why November 1 matters for heat-pump households
Because November 1 is the day the Massachusetts seasonal heat pump electric rate turns back on, and not every heat-pump household is on it. Starting November 1, 2025, Eversource, National Grid and Unitil began charging residential customers who heat with a heat pump a lower base distribution rate from November 1 through April 30 each year. The Department of Public Utilities lists Eversource's heat pump base distribution rate at $0.02052 per kWh against $0.06264 on the standard R-1 rate, and National Grid's at $0.02440 against $0.06677. Heat pump water heaters alone do not qualify.
Enrollment is where the lead sits. The utilities automatically enroll customers at an address that received a qualifying Mass Save heat pump rebate, or had a heat pump installed through Mass Save, since January 1, 2019. Everyone else has to self-enroll through their electric company. By April 2026, the utilities told WBUR, about 140,000 households had enrolled.
So a heat-pump record in your permit feed describes one of two households. One installed through Mass Save and was enrolled automatically. The other installed without a rebate, perhaps with a non-qualifying unit after the 2026 refrigerant change, and may be paying the full winter distribution rate on a house now heated by electricity. The permit does not tell you which. A one-line note does: "If your heat pump went in without a Mass Save rebate, check that you are on the seasonal heat pump rate before November 1." It costs nothing and opens the service-contract, backup-heat and panel conversations. Point them to their electric company; the utility runs the enrollment.
How should each trade use the ratio?
Match the offer to the town's band. The table below is the working version.
| Band (heat pumps per boiler) | Towns in this set | Who should prioritize it | Lead to open with |
|---|---|---|---|
| 0.75 and above | Otis, Mattapoisett, Somerville, Melrose, Easthampton, Holliston, Sherborn | Heat-pump service companies, electricians, generator installers, smart-thermostat and AV integrators | Annual heat-pump maintenance, backup heat, panel capacity, the seasonal-rate check before November 1 |
| 0.45 to 0.74 | Holden, Milton, Belmont, Hanson, Concord, Acushnet, Bellingham, Falmouth, Weston | Full-line HVAC contractors | Both offers, split by record: fuel-switch follow-up on heat-pump records, adjacent work on boiler records |
| Under 0.45 | Randolph, Lynnfield, Billerica, Braintree, West Bridgewater, Hingham, Rockland, Pembroke, Taunton | Boiler and furnace shops, chimney liner crews, oil and propane dealers, tank removal | Chimney liner after a new gas boiler, tank removal, the spring heat-pump conversation for next year |
Then overlay the direction column. A low-band town whose share jumped (Hingham, Randolph, Weston in 2026) is a market where a heat-pump installer is early rather than late, and where the boiler shops are about to lose share. A high-band town whose share fell (Somerville, Melrose) is still a large heat-pump market, but the growth argument for putting more money there is gone for now.
For the heat-pump records themselves, the electrical stream is the one to watch. In the permit-stream cut from our heating-season piece, 43% of heat-pump records were electrical permits and 37% were sheet metal. An electrical record that names a heat pump is often the service upgrade that a heat pump forces, and it names the electrician who can refer you. The HVAC contractor playbook covers how to turn those records into a route.
One timing rule holds across all three bands. Heat-pump records peak in June and boiler records peak October through January, so the ratio you see in any single month is mostly season. Rank towns on full-year or same-month comparisons only.
How permits.llc fits in
permits.llc carries 410,000+ Massachusetts permit records across 13 counties, with the work description kept where the town publishes one. Every count in this piece comes from that file.
Pull the free Massachusetts permit download, filter the description field for heat pump, mini-split, ductless, furnace and boiler, and run the ratio for the towns you actually serve. Then set up daily alerts for electrical and gas permits in those towns so the records that land in October, when boiler filings roughly double, reach you in the week they file.
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