A new furnace's price depends mostly on its type and efficiency, and on what the installation needs beyond the box: venting, a condensate drain, ductwork changes and permits. Efficiency also sets what it costs to run for the next 15 years or more.
Installed, a gas furnace of about 80,000 BTU/hr input typically runs about $3,250 to $4,100 at 80% AFUE and about $3,750 to $4,800 at 95% AFUE, roughly $3,400 and $4,050 at the mid estimate. Electric, oil and dual-fuel systems are not priced in this source and vary too much to pin to a single number. Non-weatherized gas furnaces made from December 18, 2028 must reach 95% AFUE.
Typical costs by type
These installed costs are for the gas-furnace equipment swap, by input size and efficiency, at the low, mid and high estimate.
| Input (BTU/hr) | 80% AFUE | 95% AFUE |
|---|---|---|
| 60,000 | about $3,150 to $3,850 (about $3,300 mid) | about $3,650 to $4,600 (about $3,950 mid) |
| 80,000 | about $3,250 to $4,100 (about $3,400 mid) | about $3,750 to $4,800 (about $4,050 mid) |
| 100,000 | about $3,350 to $4,300 (about $3,550 mid) | about $3,850 to $5,050 (about $4,200 mid) |
A modulating or fully condensing furnace costs more than a comparable single-stage unit. An electric furnace usually installs for less than a gas furnace but costs far more to run where gas is available, as the running-cost section shows. Oil and dual-fuel systems vary widely and are not priced in this source.
The installed-cost figures come from NREL's National Residential Efficiency Measures Database (REMDB), 2024 release, which models a retrofit replacement in 2023 dollars and gives a low, mid and high estimate. They are total installed costs, including removing the old equipment and before any rebates, so prices have generally risen since 2023. Work REMDB does not price, such as venting conversions, gas-line changes and duct changes, has no figure here and is described as a cost driver instead.
What drives the price
The equipment-swap figures above already include the furnace, the labor and removing the old unit. Venting, gas-line or duct changes are separate and come on top. The table below shows when each applies.
| Cost driver | When it applies |
|---|---|
| Ductwork changes | New runs, resizing or repairs |
| Venting change | Going from 80% (metal flue) to 90%+ (PVC) |
| Condensate drain or pump | Condensing (90%+) furnaces |
| Thermostat | New or smart thermostat |
| Permits and inspection | Most jurisdictions |
| Gas and electrical work | New gas line or a dedicated circuit |
Replacement versus a new install or fuel switch
A like-for-like replacement is the cheapest path because it reuses what the house already has: the gas line, the flue or vent, the ductwork, the electrical circuit and the condensate route. The installer sets the new unit where the old one sat and reconnects it, so most of the cost is the equipment plus labor.
A first-time install in a home that never had a furnace, or a switch from one fuel to another, adds work a straight swap skips. Running a new gas line, cutting in supply and return ducts, adding a dedicated circuit and building a vent path each add cost that a straight swap avoids. That is why a conversion quote lands well above a like-for-like replacement of the same furnace.
Moving from an 80% furnace to a condensing 90%+ model is a partial version of this. The old metal flue cannot carry the cooler condensing exhaust, so the installer adds PVC venting and a condensate drain, and the abandoned flue may need relining where a water heater shared it, or capping. See AFUE explained for why condensing units vent differently.
The 2028 federal rule
Under the DOE's rule, non-weatherized gas furnaces, the standard indoor type, manufactured on or after December 18, 2028 must reach 95% AFUE. That effectively ends new 80% gas furnaces for most homes, and means planning for PVC venting and a condensate drain. See AFUE explained.
Running cost and payback
For a 2,000 sq ft home with average insulation and 4,500 heating degree days, an 80% furnace costs about $984 a year at an assumed $1.35 per therm and a 95% furnace about $829, a $155 difference. At the mid estimate the 95% furnace costs about $650 more than the 80% unit, so on energy savings alone it pays back in about 4 years; the PVC venting and condensate drain a condensing furnace needs come on top, so the real payback is longer. The AFUE calculator runs it for your home.
Behind those figures sits a fixed heat requirement. That example home needs about 58.3 million BTU of delivered heat over a season, from the same heat-loss model the furnace sizing calculator applies to your square footage, insulation and design temperature.
An 80% furnace burns 58.3 million divided by 0.80, about 72.9 million BTU of gas, which is 729 therms; at the assumed $1.35 per therm that is the roughly $984. A 95% furnace burns 58.3 million divided by 0.95, about 61.4 million BTU, or 614 therms, which is the $829. The higher the efficiency, the less fuel buys the same heat.
An electric furnace shifts that picture even though it installs for less. Electric resistance heat turns essentially all its input into heat, so the same 58.3 million BTU needs 58,300,000 divided by 3,412 BTU per kWh, about 17,100 kWh. At $0.18 per kWh that is roughly $3,077 a year, about three times the 80% gas furnace, which is why a cheaper electric install usually costs far more to run where gas is available.
Rebates and credits
- The federal 25C tax credit ended for furnaces installed after December 31, 2025.
- HEAR rebates don't cover gas furnaces; they cover heat pumps and other electric upgrades. See HVAC tax credits and rebates 2026.
- Utility rebates for high-efficiency furnaces exist in some areas; DSIRE lists them.
Furnace or heat pump?
If your air conditioner also needs replacing, price a heat pump or a dual-fuel system alongside the furnace; see furnace vs. heat pump.
Frequently asked questions
How much does it cost to replace a gas furnace?
For a mid-size unit of about 80,000 BTU/hr input, about $3,250 to $4,100 installed at 80% AFUE and about $3,750 to $4,800 at 95% AFUE, before any venting or gas-line changes a condensing model may need.
Is a 95% furnace worth the extra cost?
Usually, especially in cold climates: in the example home it saves about $155 a year over an 80% furnace, and the 2028 rule will require it for new non-weatherized gas furnaces anyway.
Why does upgrading to a high-efficiency furnace cost more to install?
Condensing furnaces need PVC venting and a condensate drain, and the old metal flue may need relining or capping.
Are there tax credits for furnaces in 2026?
No. The federal 25C credit ended after 2025; check your utility for rebates.
Does a larger furnace cost more to install?
Yes: higher BTU output and more burner stages raise the equipment price, so a larger modulating unit costs more than a small single-stage one. Bigger is not better, though, because an oversized furnace short-cycles, wastes fuel and wears faster. Match the output to a heat-loss calculation with the furnace sizing calculator rather than overbuying.
How much does it cost to convert from oil to gas?
A conversion costs more than replacing an oil furnace with another oil furnace, because it is a new-fuel install rather than a swap. Beyond the furnace, the quote adds a gas line from the meter or a new service, removal of the old oil tank, and a vent path, each a separate line item. Price it with itemized quotes from at least two contractors, since the gas-line run and tank removal drive most of the added cost.
Sources & References
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