Boston / Dorchester
The figures on this page cover ZIP codes 02121, 02122, 02124, 02125, the codes a state office list files under Dorchester (BOSTON OFFICES BY ZIP CODE (Massachusetts Department of Children and Families), https://www.mass.gov/doc/boston-dcf-coverage-by-zip-code/download, checked 2026-10-19).
Dorchester has 142,397 residents (give or take 4,582) (ACS 2020-2024 5-year, table B01003, https://data.census.gov/table/ACSDT5Y2024.B01003?g=860Z200US02121, checked 2026-10-19), about 16,330 people per square mile.
Dorchester is about 4 miles from the Census center point for Boston in a straight line and covers 8.72 square miles of land (Census 2024 Gazetteer internal points and land area, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/, checked 2026-10-19).
At 16,330 people per square mile, Dorchester is dense enough that noise setback rules and outdoor-unit placement on a small lot are the first questions the installer works through.
Of the 54,592 occupied homes in Dorchester, 65% heat with natural gas, 7% with heating oil, 23% with electricity and 3% with propane (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=860Z200US02121, checked 2026-10-19).
Gas heats 65% of Dorchester against electricity at 23%, so most quotes here are a partial-home system that carries the shoulder seasons and the summer while the gas furnace handles the coldest nights, or a whole-home system when the house is ready for it.
Dorchester has about the Suffolk County oil share of 7% and 8 points less electric heat than the county's 31% (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=050XX00US25025, checked 2026-10-19).
12% of Dorchester homes are single-family detached, 56% are in two- to four-unit buildings and 25% are in buildings of five or more units (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=860Z200US02121, checked 2026-10-19).
A two- or three-family building is the common Dorchester case at 56% of the stock against 12% detached houses, and each unit usually gets its own small outdoor unit and its own rebate account rather than one big system for the building. With 63% of Dorchester homes rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=860Z200US02121, checked 2026-10-19), the landlord signs the quote in many of them.
Dorchester has 20 points fewer five-plus-unit buildings than the county's 45% (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=050XX00US25025, checked 2026-10-19).
Dorchester has 58,234 housing units, 53% built before 1940 and 76% before 1980, with 14% built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=860Z200US02121, checked 2026-10-19).
Dorchester has 7 points more pre-1940 homes than Suffolk County as a whole (46%) and 4 points fewer homes built after 2000 than the county's 18% (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=050XX00US25025, checked 2026-10-19). An older stock means more insulation upgrades before the heat pump goes in.
With 63% of Dorchester homes rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=860Z200US02121, checked 2026-10-19), most heat pump quotes here are landlord-driven: the landlord signs the contract and picks the equipment, and the tenant sees the lower bill.
Eversource Energy lists Dorchester among the Massachusetts communities it serves for electricity (Eversource Energy communities we serve, https://www.eversource.com/residential/services/communities-we-serve, checked 2026-10-19).
For a Dorchester address billed by Eversource Energy, the Mass Save whole-home heat pump rebate is $2,650 per ton up to $8,500, and the partial-home rebate is $1,125 per ton up to $8,500; for projects installed on or after January 1, 2027, the whole-home figure drops to $2,350 per ton capped at $7,500 (Mass Save air-source heat pump rebates, https://www.masssave.com/residential/rebates-offers-services/heating-and-cooling/heat-pumps/air-source-heat-pumps, checked 2026-10-19).
With 53% of homes built before 1940 and only 14% new enough to pass on age, the first question for a Dorchester house is insulation: the whole-home rebate wants proof the house is weatherized, and a no-cost home energy assessment is the usual way an older home shows it.
Heating design temperature: 1F. Source: ENERGY STAR Design Temperature Limit Reference Guide (2019 Edition), Suffolk County row, 99% heating, PDF page 56 of 141 (Revised 11/11/2020), https://www.energystar.gov/sites/default/files/Design%20Temperature%20Limit%20Reference%20Guide%20(2019%20Ed)%20-%20ENERGY%20STAR%20Single-Family%20New%20Homes_Rev11.pdf, fetched 2026-10-19, 99%.
That 1F figure is the Suffolk County cold-day number a Dorchester heat pump is sized against, so ask the installer to show the system's heating output at 1F, not at the milder rating-label temperature.
Ask whether the quote is whole-home or partial-home, because with 65% of Dorchester on gas and 23% already electric the two paths carry different rebate figures and different sizing.
Ask for the heat-loss calculation room by room; a Dorchester house from before 1940 (53% of the 58,234 units) rarely matches a square-footage rule of thumb.
The form on this page is the follow-up for Dorchester. The public number is the number the contractor quotes from.
No local contractor is named on this door for Dorchester yet. A request from this page goes to the first licensed shop that takes the door.