Furnace Replacement Cost (2026): $6,201 to $9,540
What a contractor's cost is in 2026 to replace a gas furnace, a central air conditioner, both together, or a boiler: what efficiency, staging, venting and a chimney liner add, the refrigerant and efficiency rules as they stand now, and person-hours on every job.
The assumptions
This model assumes
- Gas furnace 80,000 Btu, AC 3 ton, boiler 100,000 Btu unless stated
- Basement mechanical room, existing ducts or piping reused
- Job cost before markup: labor, equipment and materials, no tax
- A $225 permit allowance on each job, not in the job cost shown
- Prices from Clamp's catalog on November 11, 2026
The model, step by step
Priced through Clamp's catalog on November 11, 2026, with labor hours, for an 80,000 Btu gas furnace in a basement unless the row says otherwise. Every price in this guide is job cost before markup: what the labor, equipment and materials cost you. Each job also carries a $225 permit allowance. An 80% furnace swaps onto its metal vent. A 96% furnace usually vents in plastic pipe run outdoors, through a wall or the roof as its instructions allow, and needs a condensate drain, which is why it takes longer.
80% on the chimney
96% out the wall
Drawn for this guide in the style of Quick Clamp's sketch pad: the same basement both ways. The pad has no furnace or vent tool, so these are illustrations with typed labels. Demo data.
| Furnace | Job cost | Hours |
|---|---|---|
| 80%, like for likeMetal vent connector, no drain | $3,151 | 16 |
| 80% with a chimney liner25 ft liner | $5,801 | 26 |
| 96% single stagePlastic vent 30 ft, condensate drain | $4,770 | 22 |
| 96% two stageSame venting and drain | $5,210 | 22 |
| 96% two stage, linerLiner for the water heater | $7,860 | 32 |
| 97% modulatingSame venting and drain | $5,540 | 22 |
| 96%, 100,000 BtuLarger furnace | $5,490 | 24 |
| 96% in an atticHorizontal, slower access | $5,280 | 28 |
| 96% on propaneConversion kit | $4,924 | 22 |
Six things change the number. Clamp reads each one from the words and prices it as its own choice.
The choices
EfficiencyAn 80% furnace is $3,151 and a 96% is $4,770. One online seller listed the same brand's 80,000 Btu furnace at $1,285 in 80% and $1,986 in 96% on November 10, 2026, equipment only.
StagingTwo stage adds $440 and modulating $770 over single stage.
SizeA 100,000 Btu furnace is $5,490 against $4,770 at 80,000. Size it from a load calculation, not the old nameplate.
FuelPropane adds the conversion kit: $4,924.
LocationAn attic furnace is $5,280 and 28 hours.
Chimney linerA 25 ft liner adds $2,650 and 10 hours.
A 3 ton air conditioner with its matched coil and a new 25 ft line set is $6,159 and 23 hours. That includes recovering the refrigerant and hauling the old condenser and coil.
| AC | Job cost | Hours |
|---|---|---|
| 3 ton, new line setCondenser, coil, 25 ft line set | $6,159 | 23 |
| 3 ton, line set reusedFlush and pressure test | $5,905 | 22 |
| 3 ton, two stageTwo-stage compressor | $6,534 | 23 |
| 3 ton, inverterInverter compressor | $6,909 | 23 |
| 2 tonSingle stage | $4,945 | 21 |
| 4 tonSingle stage | $7,374 | 24 |
| 5 tonSingle stage | $8,588 | 26 |
| 3 ton condenser onlyCoil and line set stay | $4,450 | 18 |
What changed with the refrigerant
New equipmentNewly manufactured residential split systems use a refrigerant with a global warming potential (GWP) under 700, such as R-454B or R-32. Both are mildly flammable (A2L).
Old stockEPA removed the January 1, 2026 installation deadline for R-410A systems whose components were all made or imported before 2025. The change took effect July 27, 2026. State rules can be stricter: Washington still bars R-410A in new installs.
The coilA new outdoor unit needs an indoor coil the manufacturer approves for it. Do not keep an R-410A coil and charge it with a new refrigerant.
The line setReusing it saves $254 here, if the manufacturer's instructions allow it for the length and size. Flush, pressure test, evacuate and charge by the instructions.
Replaced on one visit, a 96% furnace and a 3 ton AC are $10,609 and 46 hours. Priced apart they add up to $10,929, and two permits instead of one. The system price does not carry the furnace's plastic vent pipe, $285 on the furnace alone, so add it and the two are within $35.
| System | Job cost | Hours |
|---|---|---|
| 80% furnace, 3 ton ACSingle stage | $9,499 | 42 |
| 96% furnace, 3 ton ACSingle stage | $10,609 | 46 |
| 96% two stage, 3 tonTwo-stage furnace | $11,049 | 46 |
| Two stage, two stageTwo-stage furnace and AC | $11,424 | 46 |
Priced for a 100,000 Btu gas boiler. The four types are different jobs. A cast iron hot water boiler goes back on the chimney. A condensing boiler vents in plastic and drains condensate. A combi also makes the domestic hot water. A steam boiler is rebuilt at its near-boiler piping.
Three boilers
Drawn for this guide in the style of Quick Clamp's sketch pad: three boilers and how each one vents or pipes. The pad has no boiler tool, so this is an illustration with typed labels. Demo data.
| Boiler | Job cost | Hours |
|---|---|---|
| Cast iron, hot waterVents to the chimney | $6,285 | 32 |
| Cast iron with a liner25 ft liner | $8,935 | 42 |
| CondensingPlastic vent 40 ft, drain | $7,665 | 34 |
| CombiHeat and hot water | $8,145 | 38 |
| SteamNear-boiler piping | $8,485 | 40 |
| Condensing, more partsCirculator, tank, 3 zone valves | $9,335 | 40 |
| Cast iron, oilOil burner | $7,125 | 32 |
Before you quote a boiler
Steam sizingSize a steam boiler to the connected radiation, in square feet, against the boiler's square-foot steam rating. The home's heat loss is the wrong number.
Steam pipingPipe the risers, header and equalizer to the manufacturer's diagram. Clamp prices that as labor; the pipe and fittings are not a line yet, so add them.
CondensingPlan the vent route, the condensate drain and the piping arrangement the manufacturer requires.
PartsA circulator, an expansion tank and three zone valves take the condensing boiler to $9,335.
Checked on November 11, 2026. The tax credit ended and the refrigerant deadline was lifted in the last year, the furnace rule is under challenge, and several cost pages still show the old version.
What applies now
Furnace minimum80% AFUE for a non-weatherized gas furnace. A 95% rule applies to furnaces manufactured on and after December 18, 2028. That date stands for now: DOE took comment through May 27, 2026 on a petition to move it to 2030 and has not ruled, and the court decision upholding the rule was vacated in June 2026 and is back before the appeals court.
AC minimum13.4 SEER2 in the North, by date of manufacture. 14.3 SEER2 under 45,000 Btu/h in the Southeast and Southwest, by date of installation, with EER2 minimums in the Southwest.
Boiler minimum84% gas hot water, 82% gas steam, 86% oil hot water, 85% oil steam.
Tax creditThe federal energy efficient home improvement credit (Section 25C) does not apply to anything placed in service after December 31, 2025. A 2026 install gets no federal tax credit.
SizingThe residential code sizes equipment by ACCA Manual S on Manual J loads, or another approved method.
Published times are clock hours on site and rarely name the crew. Two installers for six hours is 12 person-hours. Clamp's hours are person-hours.
Published times beside Clamp's hours
Furnace, straight swapLennox says 4 to 6 hours, crew not stated. Angi says 4 to 8 and that it often takes two installers. Clamp: 16 person-hours.
Furnace, 96% conversionLennox puts gas furnace installs at 6 to 10 hours. Clamp: 22 person-hours with the venting and drain.
Steam boilerOne installer on a trade forum plans two days, with part of the second for cleaning and skimming. Clamp: 40 person-hours.
A two-story house in a cold climate has an 80,000 Btu 80% furnace and a gas water heater on one chimney, and a 3 ton AC at the end of its life. Option A swaps the furnace like for like: $3,151 and 16 person-hours. Option B installs a 96% two-stage furnace, runs the plastic vent and lines the chimney for the water heater: $7,860. Option C replaces the furnace and the AC together with a 96% two-stage furnace and a 3 ton condenser and coil: $11,049 and 46 person-hours, before any liner.
| Line | Job cost | Hours |
|---|---|---|
| 96% two-stage furnace1 ea | $2,640 | |
| 3 ton condenser1 ea | $2,500 | |
| Set the furnace1 ea | $1,700 | 20.0 |
| Set the condenser1 ea | $975 | 14.0 |
| Evaporator coil1 ea | $850 | |
| Commission and balance1 ea | $550 | 3.0 |
| Remove the old condenser and coil2 ea | $450 | 2.5 |
| Set the coil1 ea | $380 | 2.5 |
| Condensate drain1 ea | $300 | 1.5 |
| Install consumables1 ea | $285 | |
| Line set, 25 ft28.75 lf | $244 | |
| Run the line set25 lf | $175 | 2.3 |
The job
Every line priced
The job in Clamp, and the estimate it prices: $11,049 at job cost, by trade. Recreations of the Clamp app with demo data.
What it means
Every furnace, AC and boiler, line by line
Clamp reads the efficiency, staging, fuel, tons, compressor type, line set and boiler type from the words, and prices the equipment, venting, drain, removal and permit, with labor hours on each line.
The equipment is half the job. The venting, the coil and the piping decide the rest.
Questions
How much does it cost to replace a furnace?
In Clamp's catalog an 80,000 Btu gas furnace is $3,151 in job cost before markup for an 80% swap and $4,770 for a 96% furnace with its plastic venting and condensate drain, each plus a $225 permit. The ballpark price range for the 96% furnace is $6,201 to $9,540.
How much does it cost to replace an AC unit?
A 3 ton central air conditioner with its matched coil and a new line set is $6,159 in job cost before markup in Clamp's catalog, about 23 person-hours. The ballpark price range is $8,007 to $12,319. Newly manufactured systems use a refrigerant with a global warming potential under 700 and need an indoor coil the manufacturer approves for the outdoor unit.
How much does a boiler replacement cost?
For a 100,000 Btu gas boiler, Clamp's catalog prices cast iron hot water at $6,285, condensing at $7,665, a combi at $8,145 and steam at $8,485 in job cost before markup. Steam costs more: in the catalog the boiler itself is $1,400 more than cast iron and the near-boiler piping adds 8 hours.
How long does it take to replace a furnace?
Lennox puts a straight replacement at 4 to 6 hours on site and gas furnace installs at 6 to 10, without naming the crew. Clamp carries 16 person-hours for an 80% swap and 22 for a 96% furnace with new venting and a drain.
Is there a tax credit for a new furnace or AC in 2026?
No. The IRS says the energy efficient home improvement credit (Section 25C) does not apply to property placed in service after December 31, 2025, so a furnace, boiler or air conditioner installed in 2026 gets no federal tax credit.
Sources & provenance
- Clamp's catalog, priced by script Clamp (research)
- 10 CFR 430.32, Energy and water conservation standards and their compliance dates eCFR (official source)
- Energy Conservation Standards for Consumer Furnaces, final rule US Department of Energy (official source)
- Energy Conservation Program: Notification of Petition for Rulemaking US Department of Energy (official source)
- Phasedown of Hydrofluorocarbons: Reconsideration of Certain Regulatory Requirements US Environmental Protection Agency (official source)
- 2023 central air conditioner standards: frequently asked questions US Department of Energy (official source)
- FAQs for modification of sections 25C, 25D, 25E, 30C, 30D, 45L, 45W and 179D under Public Law 119-21 IRS (official source)
- 2021 International Residential Code, M1401.3 Equipment and appliance sizing International Code Council (official source)
- 2021 International Residential Code (New Jersey edition), Chapter 24 Fuel Gas, G2425.15 International Code Council (official source)
- ML14KC1 air conditioner installation instructions (508603-01) Lennox (research)
- Sizing a steam boiler U.S. Boiler Company (research)
- How long does it take to install a furnace? Lennox (research)
- How long does it take to install a furnace? Angi (research)
- Steam install labor estimates HeatingHelp.com forum (research)
- 80,000 Btu 80% AFUE single-stage gas furnace, product page HVACDirect (research)
- 80,000 Btu 96% AFUE single-stage gas furnace, product page HVACDirect (research)
- How much does boiler replacement cost? This Old House (research)