HVAC Replacement Cost in Boston, MA
Replacing an HVAC or heating system in Boston looks different depending on whether you own a triple-decker with steam heat, a brownstone with hot-water radiators, or a newer condo with ducts. This guide breaks down 2026 replacement costs and how Mass Save rebates and the HEAT Loan can offset the price.
By Jason Green · HVAC · Published September 14, 2026 · Updated September 14, 2026 · 7 min read
Replacing a boiler in an older Boston home
Steam and hot-water boiler replacements are among the most common major HVAC projects in Boston's triple-deckers and brownstones, given how much of the housing stock still relies on this heat source. Costs depend on boiler size, fuel type, and whether existing piping and radiators need updating alongside the new unit.
Oil-to-gas boiler conversions require a new gas permit and inspection by the City of Boston Inspectional Services Department, and only a licensed gas fitter can complete the gas piping and connection.
Installing a ductless mini-split system
For homeowners without existing ductwork, a mini-split heat pump system is the most common way to add efficient cooling and supplemental heating. Single-zone systems cover one or two rooms, while multi-zone systems can serve a whole triple-decker unit or brownstone floor.
Mini-split installations are also the equipment category most commonly eligible for Mass Save's heat pump rebates, which can significantly reduce the net cost.
Central AC and ducted heat pump replacement
Homes in Charlestown, Brighton, and Jamaica Plain with existing ductwork can often replace a central AC system or add a ducted heat pump more cost-effectively than a fully ductless retrofit, since the distribution system is already in place.
A whole-home ducted air-source heat pump that replaces both heating and cooling equipment is the highest-cost option upfront but can qualify for the largest Mass Save rebates.
Using Mass Save rebates and the HEAT Loan
Mass Save offers heat pump rebates that can meaningfully reduce the net cost of a qualifying system, along with a 0% interest HEAT Loan that can be used to finance the remaining balance.
Ask your contractor to confirm they are a Mass Save-participating installer and to walk through current rebate tiers and HEAT Loan eligibility before finalizing your replacement quote.
Typical cost ranges
| Gas furnace replacement | $5,500 - $10,500 |
| Steam boiler replacement | $8,000 - $15,000 |
| Hot-water boiler replacement | $8,500 - $16,000 |
| Single-zone mini-split install | $4,000 - $8,500 |
| Multi-zone mini-split install (3-4 heads) | $11,000 - $22,000 |
| Central AC replacement (ducted home) | $6,500 - $13,000 |
| Whole-home ducted air-source heat pump | $14,000 - $28,000 before rebates |
| Oil-to-gas conversion (equipment plus piping) | $9,000 - $18,000 |
Ranges are general estimates gathered from homeowner-reported quotes, not an offer or a quote for your project.
Common questions
How much can Mass Save rebates reduce a heat pump replacement?
Rebate amounts vary by household income and system type, and can meaningfully lower the net cost of a qualifying heat pump; ask a Mass Save-participating contractor for current figures for your specific project.
Is it cheaper to replace a boiler or switch to a heat pump?
A like-for-like boiler replacement is usually cheaper upfront, but a whole-home heat pump can offer lower operating costs and larger Mass Save rebates over time, so the better choice depends on your home's insulation, budget, and long-term plans.
Do I need a permit to replace my furnace or boiler?
Yes, any furnace or boiler replacement requires a permit from the City of Boston Inspectional Services Department, and gas equipment requires an additional gas permit.
How long does a mini-split installation take in a Boston triple-decker?
A single-zone install typically takes one day, while a multi-zone system serving a whole unit can take two to three days depending on line-set routing and electrical work.
What is the Mass Save HEAT Loan?
It's a 0% interest financing program offered through Mass Save that homeowners can use to cover heat pump, insulation, and related efficiency upgrades, reducing the upfront cash needed for a replacement project.
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