Gas tankless water heater replacement cost in Boston, MA
Installed, About 180,000–199,000 BTU (2–3+ bathrooms)
A typical tankless water heater (About 180,000–199,000 BTU (2–3+ bathrooms)) costs about $3,100 installed in the Boston area, 11% above the national figure, because plumbers here earn a median $47 an hour against $31 nationally.
Prices by size in Boston
| Size | Low | Typical | High | National typical |
|---|---|---|---|---|
| About 150,000 BTU (1–2 bathrooms) | $2,150 | $2,950 | $3,900 | $2,650 |
| About 180,000–199,000 BTU (2–3+ bathrooms) | $2,650 | $3,100 | $4,250 | $2,800 |
Local labor: what plumbers earn here
| Hourly wage | Boston metro | United States |
|---|---|---|
| 25th percentile | $30 | $24 |
| Median | $47 | $31 |
| 75th percentile | $57 | $41 |
The Boston market
Boston's Inspectional Services Department requires a plumbing permit to replace or install a water heater or boiler when no other work, such as opening walls, is involved. These permits are available to licensed contractors only: a homeowner must hire someone with a valid Massachusetts trade license to apply and do the work. The fee is a $20 application fee plus $5 per fixture, though the city does not say whether a water heater counts as one fixture. After the job, the contractor schedules an inspection through the ISD call center and must be on site for it. City pages checked do not cover furnace, central AC or heat pump replacement, or a separate gas permit for gas heaters, so check with ISD. Older housing shows in the data: EIA found 26% of Massachusetts homes heat with a boiler and 15% heat water with fuel oil. Cambridge, Newton and New Hampshire towns have their own departments.
Triple-deckers and older single-family homes often vent the water heater into a shared chimney with the boiler. A gas tankless unit vents separately, which can leave the boiler alone in a flue sized for two appliances. Ask the licensed plumber how the remaining appliance will vent before you commit. Basements in older Boston homes get crowded. A wall-hung unit frees floor space around the boiler, so ask where it will mount and where the vent will exit.
Permits in Boston
| Permit for this job | Yes (source) |
|---|---|
| Fee | $20 application fee plus $5 per fixture (plumbing permit) |
| Who can pull it | Massachusetts-licensed contractor only; homeowners must hire one |
| Inspection | Yes |
Rebates in Massachusetts
HEAR: status unclear. HOMES: status unclear. Source: Massachusetts Department of Energy Resources (DOER), checked October 13, 2026.
- Mass Save: Utility collaborative: heat pump (air-source, ground-source) rebates, 0% HEAT Loan, income-based enhanced offers
- Mass Save/state interest-free home energy loans: Interest-free loans 'up to $25,000 for insulation, heat pumps and related improvements' (announced 2026-09-03)
What these programs cover, and other states
Other systems in Boston
- Gas tank water heater
- Gas furnace
- Central air conditioner
- Heat pump (ducted, outdoor unit + air handler)
Gas tankless water heater cost in other metros
Sources
- City of Boston: Install or replace a water heater or boiler
- City of Boston: Plumbing permit
- Mass Save: residential programs
- Mass.gov: interest-free loans for home energy upgrades (Sept 2026)
- EIA, 2020 RECS: Highlights for space heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for water heating in U.S. homes by state
- EIA, 2020 RECS: Highlights for air conditioning in U.S. homes by state
- https://www.boston.gov/boston-permitting/install-or-replace
- BLS OEWS May 2025, Boston-Cambridge-Newton, MA-NH (47-2152 plumbers)
- DOE Gas-fired Instantaneous Water Heaters Final Rule TSD (Dec 2024), Table 8.2.6 (2023$)