Boiler
Boiler Replacement Cost Calculator
Installed cost for residential boiler replacement by fuel, efficiency tier, and state. Includes a head-to-head comparison with air-to-water heat pumps for hydronic systems.
Quick answer: standard 85% AFUE cast-iron gas boiler installs for $4,500–$8,500. Condensing 95%+ runs $7,500–$14,000. Oil boilers $8,000–$15,000. The federal 25C credit expired Dec 31 2025; HEEHRA is electric-only. Hydronic heat-pump alternative: $14,000–$30,000 with no fuel combustion.
Optional — auto-sets state
Installed cost · Condensing 95% AFUE · Massachusetts
$12,900
range $9,250 – $17,250
Hydronic heat-pump alternative
$23,000
Air-to-water heat pump for hydronic distribution
AFUE
95%
Climate zone: 5A
Cost breakdown
- Equipment$6,000
- Labor (state-adjusted)$6,500
- Permit & inspection$400
- Total (mid)$12,900
Hydronic + heat pump?
Air-to-water heat pumps (SpacePak, Chiltrix, Arctic Heat Pumps, Mitsubishi Ecodan) connect to your existing radiator/baseboard distribution. Capital cost is higher than a boiler — $14k–$30k installed — but operating cost is 50–65% lower, and you eliminate the carbon-monoxide and combustion risks of fuel-burning equipment.
Hydronic heat pumps typically work best with low-temperature distribution (in-floor or wall panel). Older high-temperature cast-iron baseboard may need supplemental backup.
Quote check — what to ask
- · Heat-loss calculation in writing (Slant/Fin, Hydronics Institute IBR, or ACCA Manual J for hydronic).
- · AFUE and net rating both stated. Older nameplates list "input BTU" — what matters is net delivered.
- · Outdoor reset control included (cuts fuel ~10–15% by lowering supply temp on milder days).
- · Combustion analyzer printout from startup (CO, O2, stack temp). Without it, the install isn't tuned.
- · Expansion tank, low-water cutoff, and pressure relief valve replaced — they're consumables.
- · Indirect water heater integration if the old boiler did DHW too.
- · Asbestos abatement quote if existing pipe insulation is suspicious (pre-1980 homes).
New to boiler replacement?
A residential boiler heats water (or steam) that circulates through radiators, baseboard, or in-floor tubing. Unlike forced-air furnaces, boilers don’t move air — heat transfer happens through radiation and convection from the radiator surface. They’re common in the Northeast and Midwest US, mostly in homes built before 1960. Modern condensing boilers reach 95–97% AFUE; older cast-iron units are typically 80–85%. Lifespan is 15–40 years depending on construction and water quality.
Read the full guide → 11-min read · condensing vs cast-iron · oil-to-gas conversions · hydronic heat pumps · brand reliability
Frequently asked questions
How much does a boiler replacement cost in 2026?
A standard 85% AFUE cast-iron natural gas boiler installs for $4,500–$8,500. A condensing 95%+ AFUE wall-mounted boiler runs $7,500–$14,000. Premium modulating units (Viessmann, Lochinvar Knight, Buderus) land $10,000–$18,000. Oil boilers are $8,000–$15,000; propane is similar to natural gas plus a tank if needed.
Is the 25C credit available for boilers in 2026?
No. The federal 25C credit for high-efficiency boilers terminated 2025-12-31 (OBBBA). HEEHRA / DOE Home Energy Rebates are statutorily electric-only — no federal incentive on fuel-burning boilers in 2026. Some gas utilities still offer $300–$800 rebates on 95%+ AFUE installs; check your utility’s residential efficiency page.
Cast-iron sectional vs condensing wall-mount — which lasts longer?
Cast-iron sectional boilers (Burnham, Slant/Fin, Weil-McLain CGi) often run 25–40 years with maintenance, but at 80–85% AFUE. Condensing wall-mount boilers (Navien, Rinnai, Lochinvar Knight, Viessmann Vitodens) deliver 95–97% AFUE but have shorter lifespans (12–20 years) — the stainless heat exchanger is the failure point, and proprietary parts are expensive. The choice is durability vs efficiency.
Can I switch from a boiler to a heat pump?
Yes, but the path matters. Air-to-air heat pumps require new ductwork — a major retrofit if your home has no ducts (most boiler-heated homes don’t). Air-to-water heat pumps (SpacePak, Chiltrix, Arctic, Mitsubishi Ecodan) connect to your existing radiators or baseboard and deliver hot water at heat-pump efficiency. Capital is $14,000–$30,000, but you eliminate fuel-burning entirely.
Why are condensing boilers cheaper to run?
A condensing boiler recovers heat from the exhaust before it leaves the flue, including the latent heat in water vapor (combustion produces ~1 lb of water per cubic foot of natural gas). At 95–97% AFUE, almost all fuel energy ends up in your home. Non-condensing boilers waste 15–20% up the chimney.