Furnace Replacement Cost in 2026

Replacing a gas furnace by itself costs $4,350 to $8,600 installed in 2026 — a mid of about $6,150 for a 2,000 sq ft home with reusable ducts, including hauling the old unit away and pulling the mechanical permit. Step up to a 96% AFUE condensing furnace and the same job runs $6,050 to $11,100 (mid $8,450). Two decisions move that number more than anything a salesperson will show you: whether you buy the condensing unit, and whether you replace the air conditioner on the same visit.

What's inside the number

A furnace-only replacement is a short parts list. Here's what our engine prices on the reference home — 2,000 sq ft, mixed climate, average insulation, existing ductwork reusable — at standard 80% AFUE:

Line item	Low	Mid	High
Gas furnace (100k BTU, 80% AFUE, installed)	$3,800	$5,200	$7,000
Old-system removal & disposal	$300	$500	$800
Mechanical permit allowance	$250	$450	$800
Total — national average	$4,350	$6,150	$8,600

Those are engine outputs; enter the same home in the HVAC cost calculator and you'll see the same three numbers. The equipment line lands squarely inside the market: HomeGuide's 2026 gas furnace data puts an 80% AFUE furnace at $3,800–$6,200 installed, and Angi reports an average near $7,000 for a 1,600–2,000 sq ft house across all efficiency levels.

One honest note about our model: it prices the furnace by efficiency tier, not by BTU input size. A 120k unit does cost a contractor more than an 80k unit, but the spread between sizes is small next to the spread between an 80% and a 96% machine — which is why the tier is the line worth negotiating and the size is the line worth verifying.

Two adders decide whether your quote resembles the table. If the ducts need sealing and repair, add $800–$2,500; if they need replacing outright, our model charges $1.20–$3.20 per sq ft of home — $4,000 at mid on 2,000 sq ft, which is a bigger number than the furnace.

80% or 96%: the only expensive choice you make

Tier	What it is	Furnace line	Total, furnace only
Standard	80% AFUE, single-stage	$3,800–$7,000	$4,350–$8,600 (mid $6,150)
High	96% AFUE condensing, two-stage	$5,500–$9,500	$6,050–$11,100 (mid $8,450)
Premium	96% AFUE, variable-speed modulating	$6,500–$11,000	$7,050–$12,600 (mid $9,750)

The step from 80% to 96% costs about $2,300 at mid in our engine. What you're buying is the difference between sending 20% of your gas up the flue and sending 4%, and the value of that depends entirely on how many hours the burner runs. Our climate factors make the argument concretely: a 2,000 sq ft home's heating load is 100,000 BTU/h in a freeze-thaw climate and 50,000 in a hot-sun climate. Buy the condensing furnace in Minnesota, Michigan, or upstate New York. In Texas, Florida, or Arizona, the payback on a furnace that runs a few hundred hours a year rarely closes inside the unit's life — take standard efficiency and put the money toward the cooling side.

There's a physical catch worth knowing before you commit. A 96% furnace condenses flue gas, so it vents cool exhaust through PVC out a sidewall and needs a condensate drain, while an 80% furnace vents hot gas up a metal flue. If your old furnace shared a masonry chimney with the water heater, going condensing orphans that water heater in a chimney now far too large for it — the fix is a properly sized liner, and it is not in any furnace quote by default. Our estimate excludes flue relining explicitly. Ask about it before you sign, not after the crew is on the roof.

The 2028 rule, and why it doesn't change your 2026 decision

The federal minimum for non-weatherized gas furnaces has been 80% AFUE since 2015. DOE's final rule on consumer furnace standards raises that to 95% AFUE for units manufactured on or after December 18, 2028 — a threshold non-condensing technology can't reach, so 80% models effectively leave production for indoor residential use. What that means for a 2026 buyer: an 80% furnace is still legal, still stocked, and still installable, and one you buy now can be repaired and operated indefinitely. Don't let anyone sell you a condensing unit on the grounds that the cheaper one is about to become illegal. Buy it because your heating season is long.

Sizing: what your house actually needs

Furnaces are sold by input BTU/h; what heats your house is input × AFUE. That gap is why the same load lands on different boxes: a 70,000 BTU/h load needs a 100k input furnace at 80% AFUE (an 80k unit delivers only 64,000) but fits an 80k unit at 96% AFUE, which puts out 76,800. Our screening calculation for a 2,000 sq ft home:

Climate	Heating load	Input size @ 80% AFUE	Input size @ 96% AFUE
Hot-sun (AZ, TX, S. CA)	50,000 BTU/h	80k	60k
Humid (Gulf, Southeast)	60,000 BTU/h	80k	80k
Temperate (Pacific NW, mid-South)	70,000 BTU/h	100k	80k
Mixed (Mid-Atlantic, lower Midwest)	80,000 BTU/h	100k	100k
Freeze-thaw (Upper Midwest, Northeast)	100,000 BTU/h	over the residential ceiling	120k

That last cell is a real finding, not a formatting quirk. The largest residential furnace our data carries is 120k input, which delivers 96,000 BTU/h at 80% AFUE — short of the 100,000 a 2,000 sq ft freeze-thaw home needs. At 96% AFUE the same box delivers 115,200 and fits comfortably. In cold climates, past roughly 2,000 sq ft, the condensing furnace stops being an efficiency upgrade and starts being the way the equipment fits in one unit.

The envelope matters as much as the floor area. Hold the mixed-climate 2,000 sq ft home constant and change the house: poor insulation takes the load from 80,000 to 92,000 BTU/h, pre-1980 construction to 88,000, 10-foot ceilings to 100,000, and all three together to 126,500 — a 58% increase with not one square foot added. This is a screening estimate, not an ACCA Manual J; a contractor has to run the room-by-room calculation before ordering. The full sizing walkthrough, cooling included, is in what size HVAC do I need.

Furnace alone, or with the AC

The bundling question has a dollar answer in our engine:

Scope	Low	Mid	High
Furnace only	$4,350	$6,150	$8,600
AC only (4 tons, keeping the furnace)	$6,550	$9,350	$13,200
Both, done separately	$10,900	$15,500	$21,800
AC + furnace, one job	$10,350	$14,550	$20,200

Doing them together saves $950 at mid — and every dollar of it is a duplicated removal charge ($500) and a second permit ($450). That's the floor on the savings, because our model doesn't credit the shared labor day, the single crew mobilization, or the matched indoor coil you get from one manufacturer's pairing. The practical rule: if the AC is within about three years of the furnace in age, replace both now. If the AC is meaningfully newer, replace the furnace alone and make sure the new blower is compatible with the existing coil. If you're replacing both anyway, the honest question isn't which furnace — it's whether a single heat pump should replace both boxes, which we price head-to-head in heat pump vs. furnace + AC.

Where you live moves all of it. Same furnace, same house, only the regional labor multiplier changes: a mid of $5,351 in Arkansas and Mississippi (0.87×), $6,150 at national average, $7,995 in New York (1.30×), $8,303 in California (1.35×). Every state is priced in the HVAC cost by state report and in HVAC replacement cost by state.

Signs it's actually time

Most gas furnaces last 15 to 20 years, with condensing units at the upper end of that when maintained (Carrier). The common field heuristic is the $5,000 rule: multiply the repair quote by the furnace's age in years, and replace if the product clears $5,000. A $400 repair on a 14-year-old furnace scores $5,600 — replace. The rule has two blind spots. It ignores your gas bill, so an 18-year-old 80% unit limping along can lose the argument on operating cost before it loses it on repairs. And it's the wrong tool entirely for a cracked heat exchanger: a technician who finds one will condemn the furnace and shut off the gas, because that crack is a carbon monoxide path into the supply air. That's not a repair-versus-replace decision, it's a replacement with a deadline.

The symptoms that precede all of this are unglamorous and easy to ignore: burner flames that run yellow and lazy instead of crisp blue, soot around the cabinet, short cycling, rooms that never catch up, and a gas bill climbing against a flat rate. One of those is a service call. Three together is a quote.

If you don't heat with gas

Our engine prices gas furnaces, so an electric furnace is outside what we model. For scale, Angi's 2026 electric furnace data puts installation at $2,247–$8,116, with most homeowners near $5,148 — cheaper to buy than gas and, in most of the country, considerably more expensive to run, because resistance heat delivers exactly one unit of heat per unit of electricity. If you're on electric resistance heat today, the replacement worth pricing isn't another electric furnace; it's a heat pump, which moves three or more units of heat per unit of electricity in mild weather. That comparison, with the operating-cost crossover math, lives in heat pump vs. furnace + AC, and the ductless version in ductless mini-split cost.

No federal credit in 2026

Through 2025 the 25C Energy Efficient Home Improvement Credit returned 30% of a qualifying high-efficiency furnace, capped at $600. It expired December 31, 2025, and the "placed in service" date controls: a furnace running by that date can still be claimed on a 2025 return via IRS Form 5695, while a 2026 install gets nothing federal. State HEAR and HOMES rebates and utility incentives survived, and they're worth twenty minutes of searching before you sign. The full picture is in the heat-pump tax credit, explained.

What our number leaves out

Sizing here is a screening calculation from square footage and climate, not a Manual J. The estimate excludes gas-line work, flue relining, asbestos abatement, and structural chases for new ducts — and on a furnace swap specifically, flue relining is the change order most likely to appear. Get three local quotes and compare the line items, not the bottom number: the duct, permit, removal, and venting lines are where bids actually diverge. For the whole-system view, see HVAC replacement cost.

Get your number

Your total depends on square footage, climate, efficiency tier, duct condition, and state — each a field in our calculator. Enter your home and get the low/mid/high with the furnace size and every line item shown.

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