Boiler Replacement Cost in 2026: Gas, Oil & Combi

A boiler heats your home by circulating hot water (or steam) through radiators, baseboards, or radiant floors — and when one fails in January, replacement can’t wait. A new boiler typically costs $4,500–$10,500 installed in the US in 2026. This Old House puts most replacements at $4,500–$10,000; Modernize’s survey centres higher, at $6,500–$11,500. Gas is the most common fuel, oil dominates in the Northeast, and combi boilers are the fastest-growing option for smaller homes.

Quick Answer: Boiler Replacement Costs by Fuel Type

Boiler type	Typical installed cost (US, 2026)
Gas, standard efficiency (80–85% AFUE)	$4,000–$7,000
Gas, high efficiency / condensing (90–96% AFUE)	$6,000–$10,500
Oil, standard efficiency	$3,300–$7,200
Oil, high efficiency	$6,300–$9,000
Combi (gas, heat + hot water)	$7,500–$12,000
Steam (gas or oil, older radiator homes)	$7,000–$12,500
Electric	$1,800–$8,000

HomeGuide puts a straightforward gas replacement at $4,000–$9,000 installed (unit alone: $1,400–$5,600); Angi’s 2026 national average is about $5,910. Like-for-like swaps sit at the bottom of these ranges; condensing conversions with new venting sit at the top. (AFUE = Annual Fuel Utilization Efficiency — the share of fuel that becomes usable heat.)

Combi vs Heat-Only: The Short Version

The biggest choice isn’t the brand — it’s the configuration. A heat-only boiler ($4,000–$10,500, gas) heats water for radiators, baseboards, or floors while a separate tank handles showers and taps — best for larger homes with 3+ bathrooms, though it’s two appliances to maintain and eventually replace. A combi boiler ($7,500–$12,000, gas) does both jobs in one wall-mounted unit, heating water on demand with no tank — best for small-to-mid homes with 1–2 bathrooms; flow drops when several taps run together, and it needs adequate gas-line size and water flow.

Gas vs oil is usually decided by what’s on your street: where a gas line exists, gas costs less to run and needs less maintenance. Oil remains common in the rural Northeast, but budget for extras — an oil tank replacement alone runs $1,000–$6,200, plus annual burner servicing. Either way, get the boiler sized from a heat-loss calculation, not by copying the old unit’s nameplate, which was often oversized to begin with.

Where Your Money Goes

• Equipment (roughly 40–55% of the total). The boiler itself — HomeGuide lists gas units at $1,400–$5,600 and oil units at $1,700–$6,500 before installation; condensing models sit at the top.
• Labour (roughly 30–45%). Removal and disposal of the old unit, piping, venting, fuel-line connection, condensate routing, wiring, system flushing, and commissioning — get each line in writing.
• Extras and code work (the rest — the usual surprise). Permits and inspection, a condensate pump or neutralizer, an enlarged gas line, expansion tank, a power flush, chimney liner work.

6 Factors That Change Your Price

1. Fuel and efficiency tier. Each AFUE step costs more upfront, less monthly; a standard swap to a condensing combi can double the equipment line.
2. Like-for-like vs conversion. Reusing sound piping, venting, and controls keeps you near the bottom; changing fuel or location rewrites the job.
3. Condition of the existing system. Sludge, corroded piping, and failing valves surface during replacement; a flush is cheap insurance for a new heat exchanger.
4. Venting and condensate. Condensing boilers need new PVC venting and a condensate drain (plus a neutralizer in many areas).
5. Home size and zoning. More square footage means more BTU; extra zones and radiant floors add pumps, valves, and controls.
6. Permits, code, and region. A permit and inspection are required everywhere; Northeast and metro labour runs high, and winter emergencies carry a premium.

Repair vs Replace: Quick Rules

Boilers are long-lived — 15 years is a floor, and cast-iron units often run 20–30 years — so “old” alone isn’t a verdict:

• The 50% rule: if a repair quote exceeds 50% of replacement cost on a boiler over 15 years old, replace. (See our furnace repair cost guide for how repair quotes are structured.)
• The age × repair rule: multiply the boiler’s age by the repair cost; if the result tops roughly $5,000, replacement usually wins.
• Safety overrides math: a cracked heat exchanger or carbon-monoxide concern means replacement now, not at the next budget review.

Permits and safety: this work involves gas or oil combustion, pressurised hot water, and venting — it requires a permit and inspection in the US, and licensed gas fitters in Canada. It is licensed-trade work, not a DIY project; this guide is cost information only.

How to Save — and an Incentives Warning for 2026

First, a warning: the federal Section 25C credit — up to $600 toward a qualifying high-efficiency boiler — ended for equipment placed in service after December 31, 2025. Several top-ranking guides still describe it as claimable on a 2026 install; per the IRS, it is not. If a quote leans on a “federal tax credit” this year, ask them to show you the current IRS page.

What replaced it is state and utility rebates, often instant discounts via participating contractors:

• Peoples Gas (Chicago): $350 for a 95% hot water boiler, $300 at 90%, and $400–$500 for a boiler with integrated domestic hot water.
• Nicor Gas (Illinois): similar rebates for qualifying high-efficiency boilers installed in 2026; apply within 90 days of installation.

Beyond rebates: replace on your schedule, not the boiler’s (a planned spring/summer job avoids the emergency premium); keep the distribution system (sound radiators, baseboards, and piping are an asset — spend on the flush instead); and right-size (a heat-loss calculation prevents paying for capacity you’ll never use). Finally, compare the alternative: with ducts (or cooling planned), price a heat pump against the boiler quote — see our heat pump installation cost guide; for the forced-air side, see our furnace replacement cost guide.

Boiler Costs in Canada

Canadian pricing runs on its own market — CAD figures as published by Canadian sources, never converted from US prices.

• Greater Vancouver (BC Wide Heating, 2026): a condensing gas boiler runs CAD $7,000–$15,000 installed; combi boilers CAD $8,000–$14,000 and up; system boilers CAD $9,000–$16,000.
• Toronto / GTA (Bison Air): an NTI FTVN Series II condensing boiler (up to 96% AFUE) is listed from CAD $9,473 installed, including TSSA-certified installation and a 1-year labour warranty.
• Ontario (Enercare): a new high-efficiency gas or propane boiler starts at CAD $11,750, including standard installation and a one-year warranty.

BC homeowners may find CleanBC and BC Hydro support on eligible upgrades — boiler eligibility is narrower than heat-pump eligibility and changes often, so confirm on the official program page.

Worked Example: A Mid-Range Boiler Swap at $7,500

Say you choose a gas condensing boiler and the quotes cluster near the middle of this guide’s typical range — ($4,500 + $10,500) ÷ 2 = $7,500. Split that $7,500 using the shares from “Where Your Money Goes” above:

• Equipment (40–55% of $7,500): $3,000–$4,125
• Labour (30–45% of $7,500): $2,250–$3,375
• Extras and code work (the rest): $0–$2,250, depending on where equipment and labour land inside their bands
• In Chicago, a Peoples Gas rebate on a 95% AFUE boiler takes $350 off: $7,500 − $350 = $7,150

Use the same split to sanity-check any real quote: if a bidder’s equipment line sits far above 55% of their total, or the extras line keeps growing, ask them to walk you through each line in writing — as the section above recommends.

Red Flags in a Boiler Quote

• Sized off the old nameplate. The new boiler simply copies the old unit’s rating — no heat-loss calculation — even though older boilers were routinely oversized.
• A dead tax credit in the quote. The price leans on the federal Section 25C credit, which ended for equipment placed in service after December 31, 2025.
• Condensing conversion, no condensate plan. A high-efficiency swap quoted with no mention of new venting, a condensate drain or a neutralizer.
• Permit and inspection absent. Gas or oil combustion work quoted with neither — both are required.
• Nothing in writing. Removal, flushing and commissioning bundled into one vague line instead of itemized costs.

Questions to Ask Before You Hire

• Will you size the new boiler from a heat-loss calculation?
• Are removal and disposal of the old boiler included in this price?
• Does the price include new venting and condensate handling for a condensing model?
• Which state or utility rebates does this quote assume — and who applies for them?
• Are the permit and inspection included, and who schedules them?

How Boiler Costs Vary by Region

Boilers are a regional technology, so prices cluster where boilers cluster. Oil dominates in the Northeast, where — as the factors above note — Northeast and metro labour runs high, and quotes sit toward the top of the national ranges; gas country generally pays less for the same class of work. Canada is its own market with its own figures, never conversions: a condensing boiler in Greater Vancouver runs CAD $7,000–$15,000 installed (see the Canada section above). And everywhere boilers are common, a mid-winter emergency replacement carries a premium a planned spring swap avoids.

Sources + How We Built This Range

Prices are typical US and Canadian ranges from the sources above, October 2026. Boiler work involves gas/oil combustion and pressurised hot water — always use a licensed heating contractor, confirm permits, and get local written quotes before committing.