Cost to Replace Furnace (2026): Full Guide

By HomeCost Guide · Updated October 2026 · 2025 figure for a standard furnace replacement including installation; gas runs higher, electric lower

Replacing a furnace costs $2,800 to $7,500 for a standard installation, averaging about $4,800 — though gas-specific replacements run $3,800 to $10,000 with venting and gas line work (Angi, July 2026). But price is half the question. The other half is whether you should replace at all: a $600 repair on a 10-year-old furnace is smart money; a $1,800 repair on a 17-year-old one funds a dying machine.

This guide centers on that decision: replacement cost breakdown plus the repair-vs-replace framework — the age test, the $5,000 rule (age × repair cost), and the 50% rule, applied together. You'll learn which repairs are worth doing, why a cracked heat exchanger ends the discussion, and how efficiency payback and fuel-switching change the math. This guide centers on that decision: the replacement cost breakdown — labor, equipment, permits, disposal — plus the repair-vs-replace framework contractors actually use, with the age test, the $5,000 rule, and the 50% rule applied together.

1. Cost to Replace Furnace (2026): Full Guide cost breakdown

Published figures span $2,800–$10,000 because they mix fuel types, tiers, and scopes. The $2,800–$7,500 band (all fuels, standard installs) and $3,800–$10,000 (gas-specific, Angi 2026) overlap heavily — your fuel and efficiency choice decides your band. Electric: $2,000–$7,000. Gas: $3,800–$10,000. Oil: $6,750–$10,000.

Where the money goes: labor vs materials vs fees

• Replacement labor$1,000–$2,500Disconnect, removal, setting the new unit, reconnecting venting/gas/electrical, commissioning. Like-for-like: 6–10 hours, two techs.
• New furnace unit$1,000–$6,500Replacements skew mid-tier (90–96% AFUE two-stage) — you're paying the install labor anyway, so the incremental efficiency upgrade is the cheapest you'll ever buy.
• Permits & code compliance$400–$1,500Mechanical permit, gas inspection, and code upgrades the inspector requires (disconnects, combustion air, CO detectors).
• Old unit removal & disposal$60–$500Haul-away, recycling, flue capping. Higher with asbestos-adjacent insulation or mercury thermostats.

Sources: Angi, Angi, HomeAdvisor, Filterbuy HVAC Solutions. Figures are national averages compiled from published industry data; your price will vary by home and location.

2. Signs replacement beats repair

Signs replacement beats repair

• Cracked or rusted-through heat exchanger. Automatic replacement — CO risk, repair costs as much as new, unit gets shut off immediately.
• 15+ years old needing a $1,000+ repair. The $5,000 rule (age × repair) confirms what the age suggests.
• Two significant repairs in two years totaling $2,000+. The pattern won't reverse; each repair buys less time.
• CO alarms or elevated CO readings. Beyond the emergency response, a CO-producing furnace is replace-don't-repair.
• Heating bills up 20–30% with no rate change. Systemic efficiency loss; a 95%+ AFUE unit pays back in 5–8 cold-climate years.

3. How a furnace replacement works

How a furnace replacement works

1. Run the framework. Age test, $5,000 rule, 50% rule. Two of three say replace — or the exchanger is cracked — and you're replacing. Get the replacement quote before authorizing repairs over $500 on older units.
2. Itemized quotes. 3–4 itemized quotes with Manual J, model numbers, venting plan, and full scope (gas, electrical, ducts, permits, disposal, commissioning). Normalize scopes before comparing prices.
3. Incentives and fuel-switch check. Confirm federal credit eligibility, utility pre-approval if needed, manufacturer rebate timing. Price the heat-pump alternative before committing to like-for-like.
4. Installation. Gas off, old unit out, new unit set, venting/gas/electrical connected, pressure test, condensate run. One day simple; up to three with extras. No heat during work.
5. Commissioning and registration. Gas pressure, temperature rise, combustion verified; thermostat programmed; walkthrough done. Permit sign-off. Register the warranty within 60–90 days; file everything.

4. What affects the cost

Replacement labor: what 'swap' includes

Replacement labor differs from first-time install. A like-for-like swap reuses gas routing, venting path, electrical, and duct transitions — essentially exchanging boxes and recommissioning: ~$1,000–$1,800. But 'replacement' often isn't like-for-like: 80%→95% AFUE means new PVC venting ($500–$2,000); relocation means new gas and vent runs ($800–$2,000); tight 1970s closets mean carpentry. The labor line tells you which project you're buying — the cheapest labor quote often skipped the venting rework you'll pay as a change order.

The repair-vs-replace framework

Three tests, used together. (1) Age: under 12, lean repair; 15+, lean replace; 12–15, let the other tests decide. (2) The $5,000 rule: age × repair cost — over $5,000, replace. A 14-year-old furnace needing a $400 repair: 5,600 → replace. An 8-year-old needing the same: 3,200 → repair. (3) The 50% rule: repair over 50% of new installed cost → replace. When two of three say replace, they're right.

Which repairs are worth doing

Replace-side: cracked heat exchanger ($1,500–$2,500+, CO risk — the furnace is done), failed secondary exchanger, multiple component failures in one season. Repair-side: ignitor ($150–$300), flame sensor ($100–$200), pressure switch ($150–$300), thermostat ($150–$400), blower motor ($400–$900) on a unit under 12. Gray zone: control boards ($400–$800) and inducer motors ($400–$750) at ages 12–15 — apply the $5,000 rule strictly. Any repair over $2,000 past age 10 deserves a replacement quote first.

The heat exchanger: what ends furnaces

The heat exchanger keeps combustion gases separate from your home's air. When it cracks (decades of thermal cycling) or rusts through (chronic condensation, oversizing), carbon monoxide can enter the airstream. The repair costs nearly as much as a new furnace, and no reputable tech patches it. Warning signs: visible cracks/rust, CO alarms, soot around the unit, a red tag. A cracked exchanger isn't a repair decision — it's a replacement mandate. Shut the unit off immediately.

Efficiency payback: the hidden side

A new furnace doesn't just end breakdowns — it cuts every future gas bill. 80%→96% AFUE saves ~17% on heating gas: ~$250/year on $1,500/year heating costs, ~$3,750 over a 15-year life — covering much of the efficiency premium. That's why the framework favors replacement more in cold, high-gas-price regions. In mild country with $400/year heating, savings run ~$70/year and the decision rests on reliability, not payback.

Fuel type and switching

Gas ($3,800–$10,000, Angi 2026) is the reference case. Electric ($2,000–$7,000): cheaper install — no venting or gas line — but ~3x the cost per BTU at typical rates in cold climates. Oil ($6,750–$10,000): the Northeast specialty, plus tank considerations. Propane conversions add $1,000–$3,000 for tank setup. The strategic question at replacement time: switch fuels? Gas-to-heat-pump can slash operating costs where electricity is cheap; oil-to-gas pays where gas is newly available. Price the switch, not just the replacement.

Bundled upgrades during replacement

Replacement is the cheapest time to fix everything around the furnace: duct sealing ($500–$1,500) with the crew on site; staging-capable thermostat ($150–$400); humidifier ($400–$800); upgraded filtration ($300–$600); condensate infrastructure ($150–$400). Each runs 20–40% cheaper inside the replacement than standalone. The trap: $3,000 of unitemized 'package' add-ons. Worthwhile extras have independent payback math — ask for it. The humidifier pays back in comfort; the UV light mostly pays the contractor — ask for the payback math on each extra.

Proactive vs emergency timing

July replacement for a furnace: shoulder pricing, open schedules, time for 4 quotes and fall rebates. January no-heat emergency: 10–20% premiums, whoever's available, decide-today pressure. A 15+ year-old limping furnace replaced proactively in the off-season — a planned $6,500 vs a $7,800 emergency replacement of identical equipment — is the single highest-ROI decision in this guide. You also get the contractor you chose, not the one who answered at 2 AM.

5. Saving money & hiring right

Questions to ask your contractor

• Walk me through the repair-vs-replace math on my unit — age, repair history, this quote?
• Is the heat exchanger intact — show me the inspection. (If cracked, the decision is made.)
• Manual J, or are you matching my old unit's size?
• Full scope itemized: venting, gas, ducts, electrical, permits, disposal?
• Quote a heat-pump alternative so I can compare fuel-switch economics?

6. How costs vary by state

Replacement costs follow regional labor; the framework works everywhere. Planning ranges adjusting the $2,800–$7,500 band — confirm with itemized local quotes.

7. Frequently asked questions