Furnace Replacement Cost

Replacing a furnace in 2026 costs $3,800–$10,000 installed for a natural gas unit — the most common type — with most homeowners paying around $5,500. Electric furnaces run $2,000–$7,000, oil $4,500–$9,000, and propane $4,000–$7,500. About 60% of the total is equipment, 25% labor, and 15% permits, removal, and extras. If your furnace is past its expected lifespan, repair bills are stacking up, or your heating bills keep climbing while rooms stay cold, replacement usually beats another repair. Planning a full system refresh? Our AC replacement cost guide covers the other half — a furnace + AC combo ($5,000–$15,000) shares labor and permits, which is the cheapest way to replace both.

2026 furnace replacement costs by fuel type

Fuel type is the single biggest price driver. Gas dominates because the equipment is mid-priced and the fuel is cheap to burn; electric is cheapest to install but most expensive to run.

The operating-cost gap matters more than the install gap over a furnace's lifetime. Natural gas costs roughly one-third as much as electricity per BTU of heat delivered (about $1.20 per therm vs. $0.17 per kWh) — which is why an electric furnace that was cheap to install can cost far more to run for 20 years. Where the money goes on a typical job: equipment about 60%, labor about 25%, and permits, old-unit removal, and extras about 15%. Quotes that seem wildly cheap are usually missing one of those three buckets — ask which.

Furnace cost by home size

Furnaces are sized in BTUs (British thermal units) of heating output. These 2026 installed ranges assume a standard gas replacement; electric runs lower, oil and propane higher:

Square footage is only the starting point — insulation quality, window area, ceiling height, and climate zone all shift the right size. A good contractor runs a Manual J load calculation instead of copying the old unit's label (the old one may have been wrong for 20 years). Oversizing is the classic homeowner-funded mistake: an oversized furnace short-cycles, wastes fuel, creates temperature swings, and wears out faster. Before you collect quotes, run your own estimate with the HVAC BTU calculator so you can spot a bid that sizes by guesswork. And if your ducts are leaky or undersized, no furnace size fixes that — see our ductwork installation cost guide for what duct repairs add.

AFUE efficiency tiers: 80% vs. 90–96% vs. 97%+

AFUE (Annual Fuel Utilization Efficiency) tells you what share of the fuel becomes heat in your home. An 80% AFUE furnace wastes 20 cents of every fuel dollar up the flue; a 97% unit wastes three. The tier you pick is a bet on fuel prices and how long you'll own the home:

Upgrading from 80% to 95%+ AFUE adds roughly $1,500–$2,500 to the installed price and typically pays for itself in 5–8 years in cold climates through lower fuel bills. In mild climates with short heating seasons, the payback stretches and the 80% unit is often the rational buy — don't let anyone upsell you efficiency you can't burn through. Two practical notes: two-stage and variable-speed furnaces also run quieter and heat more evenly (no more arctic bedrooms), and 90%+ units vent through PVC pipe out a side wall instead of a metal chimney flue, so they need a condensate drain — confirm the venting change is itemized in your quote rather than discovered on install day. In mild climates, also price the alternative: a heat pump can heat and cool in one box and may beat a furnace on lifetime cost where winters are gentle.

How furnace replacement works, step by step

Most replacements are a one-day job (4–8 hours on site). Here's what actually happens, in order:

1. Assessment and load calculation. The contractor measures your home, inspects the ductwork, checks gas line capacity, and runs a Manual J to size the unit. Get three quotes — they should all land on roughly the same BTU size.
2. Permits. Your contractor pulls a mechanical permit (typically $50–$150) and schedules any required inspection. This is their job, not yours — but confirm it's in the quote.
3. Old unit removal. Power and gas are shut off and locked out, the gas line is capped, venting and duct connections are separated, and the old furnace is hauled out. Ductwork gets a visual inspection while it's exposed.
4. New unit set and connected. The furnace is positioned and leveled, then tied into the gas line, 120V electrical, venting (PVC sidewall for 90%+ units, metal flue for 80%), condensate drain, and the supply/return duct plenums.
5. Thermostat. The old thermostat is rewired or replaced — most homeowners add a programmable or smart thermostat at this point since the installer is already at the wiring.
6. Startup and testing. The tech fires the unit, checks combustion, measures airflow and temperature rise across the heat exchanger, tests all safety switches, and checks for carbon monoxide at the vents and registers.
7. Walkthrough and inspection. You get a tour of the new equipment, filter-change instructions, and warranty paperwork. If your municipality requires it, the inspector signs off — usually within a few days.

The timeline stretches to two or three days when the job includes ductwork modifications, a fuel-type switch (say, oil to gas), or relocating the furnace. If the quote includes duct repairs, compare it against standalone pricing in our ductwork installation cost guide so you know the duct portion is fairly priced.

Furnace brands by price tier

Installed ranges below reflect typical 2026 pricing for the furnace type each brand is known for. Installation quality moves the needle more than the badge on the cabinet — a perfect install of a budget-tier unit beats a sloppy install of a premium one:

What to verify beyond the brand: a 10-year parts warranty (standard across major brands once you register the unit — unregistered units often drop to 5 years), a labor warranty of at least one to two years from the installer, and a contractor who is licensed, insured, and willing to show the Manual J. For a single room or an addition that the central system can't reach, a mini-split is often cheaper than extending ductwork — worth pricing before you upsize the furnace to cover one cold room.

Repair vs. replace: the 1/3 rule

Typical furnace repairs run $300–$1,200. The industry's rule of thumb: if a repair costs more than about one-third of a replacement, replace the unit instead. A $1,500 repair on a furnace that costs $5,000 to replace fails the test; a $400 repair on a 10-year-old unit passes it. Age sharpens the math — expected lifespans are 15–20 years for gas, 20–30 for electric, and 15–25 for oil.

Replace rather than repair when you see these signs:

• The unit is past its expected lifespan and repairs are becoming annual events. Money spent on a 22-year-old gas furnace is money you won't get back.
• Heating bills are climbing while comfort is falling — the classic signature of a heat exchanger or burner losing efficiency.
• Rooms heat unevenly despite a clean filter and open registers, pointing to airflow or capacity problems the unit can't overcome.
• A cracked heat exchanger. This is the non-negotiable one: cracks can leak carbon monoxide into your home's air. Replacement is the only safe answer, and it's urgent.
• Frequent cycling, new noises, or visible rust and soot around the cabinet — all late-life symptoms.

Repair makes sense for a younger unit facing its first major failure, especially when the fix is under a few hundred dollars. Keep up annual maintenance either way — a yearly tune-up is the cheapest life extension a furnace gets.

Costly mistakes to avoid

• Buying on price alone. The cheapest bid often skips the load calculation, reuses questionable venting, or buries the permit fee. A furnace lives 15–20 years — the lowest bid is rarely the lowest cost.
• Oversizing “just in case.” An oversized furnace short-cycles, wastes fuel, swings temperatures, and dies young. Trust the Manual J, not the instinct that bigger is safer.
• Ignoring the venting change on 90%+ units. High-efficiency furnaces abandon the chimney for PVC sidewall venting plus a condensate drain. If it's not itemized in the quote, it becomes a surprise change order on install day.
• Skipping the combo conversation. If your AC is also aging, a furnace + AC combo ($5,000–$15,000) shares labor and permits. Replacing them a year apart means paying for two installations.
• Skipping the permit. Unpermitted mechanical work can void your homeowner's insurance claim, fail a home inspection at sale time, and draw fines. It's $50–$150 — not worth skipping.
• Not registering the warranty. Most brands cut the parts warranty roughly in half if you never register the unit. It takes ten minutes online and doubles your coverage.

DIY vs. hiring a pro

Be blunt about this: gas and oil furnace installation is pro-only work. It involves gas piping, combustion tuning, venting design, and carbon monoxide safety — mistakes can be lethal, most jurisdictions legally require a licensed contractor, and manufacturers void the warranty on owner-installed units. Electric furnaces are mechanically simpler but still involve 240V high-amperage wiring, code compliance, and permits; a licensed HVAC contractor or electrician is the right call there too.

Where homeowners can legitimately save money is around the edges of the job: clearing the work area and a path to it before the crew arrives, handling the thermostat swap yourself if you're comfortable with low-voltage wiring, and changing filters on schedule afterward so the new unit actually reaches its rated lifespan. None of these replace the licensed install — they just trim the labor hours you're paying for. Get three itemized quotes, and be wary of any bid that won't put equipment model numbers in writing.

Do you need a permit to replace a furnace?

In most US municipalities, yes — furnace replacement requires a mechanical permit, typically $50–$150. The permit covers the gas connection, venting, and electrical work, and triggers an inspection that verifies the install is safe and to code. Your contractor should pull it as part of the job; confirm it's in the quote rather than assumed. Skipping it risks insurance claim denials, failed home inspections when you sell, and municipal fines. Rules vary by city and county, so check your municipality's building department if a contractor ever tells you a permit isn't needed — that's a red flag, not a discount.

Ready to size your system? Run the HVAC BTU calculator to estimate the right furnace size for your home, then turn the numbers into a quote you can send to contractors for apples-to-apples bids.