Furnace replacement cost dataset

Standard against condensing, by house size

National wages, mixed climate, basement, water heater sharing the chimney. Only the floor area changes.

The gap barely moves with house size, because almost none of it is the appliance. It is the vent pipe through the wall, the coring, the condensate drain and the chimney liner — all of which cost the same whether the furnace is 60,000 or 120,000 BTU/h. That is the single most useful thing on this page: the high-efficiency premium is close to a fixed amount, so it is proportionally worst on a small house.

The same furnace, in four places

A 95% condensing unit on the reference house. Nothing changes except where somebody has to stand to install it.

The orphaned chimney

Worth its own section because it is the line people find on the invoice rather than on the quote.

A condensing furnace vents in plastic through a wall, so it leaves the masonry chimney behind. In a very large number of American houses that chimney was also serving the gas water heater. On its own the water heater cannot fill a flue that size: the exhaust cools instead of rising, condenses inside the brickwork, and over a few winters destroys the chimney from within — while not reliably carrying the products of combustion out of the house. The remedy is a correctly sized stainless liner. On this dataset that is $737, the difference between $5,988 and $5,251. If you take one question to a high-efficiency quote, make it this one.

Climate, and the size it implies

The reference house at 2,000 square feet, standard efficiency, in each of the four climate bands the model uses.

⚠️ Those BTU-per-square-foot bands are our declared estimate, not an official table. They are wide because the envelope matters as much as the weather: a 1970s house with single glazing and a leaky attic and a 2020 house with sealed ducts do not ask for remotely the same furnace. This is a screening figure. The professional standard for sizing is ACCA Manual J, which is licensed material and is not reproduced anywhere on this site — and a real Manual J calculation usually comes back smaller than any rule of thumb.

The efficiency rule, and the date in it

10 CFR 430.32(e) sets the minimum Annual Fuel Utilization Efficiency for residential furnaces. For non-weatherized gas furnaces, the current figure is 80%, and for units manufactured on and after December 18, 2028 it becomes 95%. We took both from the regulation text on govinfo, retrieved 2026-08-23. The consequence is the whole reason this dataset separates appliance from installation: 95% AFUE means a condensing furnace, and a condensing furnace means plastic venting, a condensate drain and, very often, that chimney liner.

Line items

On the reference house, 61% of the total is installation rather than equipment, and 66% of it comes from estimated rather than official figures.

The reasoning behind each figure

Written out so a heating contractor can point at the exact assumption that is wrong.

Furnace, 80% AFUEestimated, ±33%

• Priced per thousand BTU of input, so an 80,000 BTU furnace lands around $880 to $1,760 for the appliance alone.
• The band is single-stage at the bottom and two-stage with a variable-speed blower at the top. The blower matters more than the burner for what the house feels like, and it is the part people do not ask about.
• These are manufactured goods shipped nationally, so the band is about specification and brand tier, not about where you live. What varies by area is the labour, which this model adjusts separately.

Furnace, 95%+ AFUE condensingestimated, ±31%

• Roughly $700 to $1,300 more than the equivalent 80% unit on a normal house, before any of the installation differences it forces.
• A condensing furnace has a second heat exchanger made of stainless steel, because what comes off it is mildly acidic. That is most of the price difference in the appliance itself.
• This will be the only thing on the shelf for indoor gas furnaces manufactured from December 2028, so the band is likely to narrow as volume shifts.

Electric furnace with resistance elementsestimated, ±37%

• Much cheaper as an appliance than anything that burns fuel: it is a blower, a cabinet and a bank of heating elements, with no heat exchanger and no burner to fail.
• The saving is entirely at purchase. Resistance heat costs three to four times as much to run as a heat pump doing the same job, which is why this option is worth pricing against the heat pump before choosing it.

Removal, setting and connection

• Sixteen trade hours on a basement swap: two technicians for a day. That covers taking the old unit out, setting the new one, connecting it and starting it up, and it is the number the access factor multiplies.
• Where the furnace lives changes this by up to 40%, which is why it is a question the calculator asks. It is also the single biggest reason two honest quotes on the same house can differ.
• The wage is official and regional; the hours are our estimate. There is no public productivity data for residential trades, so we say which half is which.

Supply plenum and duct transitionsestimated, ±40%

• A replacement furnace is almost never exactly the same cabinet size as the old one, so the sheet metal above and below it gets remade. This is fabricated on site or in the van, not bought off a shelf.
• It appears on every replacement and is almost never itemised in a quote, which is one reason a bare equipment price is not comparable to an installed price.

Sheet metal fabrication and fitting

• Three hours to measure, cut, fold and seal the transitions, scaled by the same access factor as the rest.

Filter cabinet and media filterestimated, ±50%

• A proper filter cabinet rather than a slot in the return. It is a small line that pays for itself: the commonest cause of a furnace failing early is a restricted filter cooking the heat exchanger.
• The band separates a one-inch frame from a four-inch media cabinet, which needs changing once or twice a year instead of monthly.

Metal flue connector to the existing chimneyestimated, ±50%

• An 80% furnace vents hot, so it can use the masonry chimney that is already there. This line is the connector between the furnace and that chimney, not the chimney itself.
• The cheapness of this line against the condensing venting below is the whole reason 80% units are still specified where they are still legal.

Sealed plastic intake and exhaust through the wallestimated, ±49%

• Two pipes, not one: a condensing furnace draws its combustion air from outside and pushes the exhaust back out, both in plastic, both sealed.
• The band is the run length and whether it exits a wall at the furnace or has to travel to reach a legal termination point — which cannot be under a window, near an air intake, or where the plume will ice a walkway.

Coring the wall and running the vent

• Four and a half hours: core through the wall, run and support two pipes, pitch them back to the furnace so condensate drains the right way, and seal both ends.
• This work does not exist at all on an 80% swap. It is the largest single reason the condensing install costs more than the condensing appliance.

Relining the chimney for the orphaned water heaterestimated, ±44%

• This is the line nobody warns you about. If the water heater shares the masonry chimney with the furnace and the furnace leaves, the flue is suddenly far too big for the water heater alone.
• A flue that is too large does not draw. The exhaust cools on the way up, condenses inside the masonry and destroys it from within, and meanwhile the products of combustion are not reliably leaving the house.
• The fix is a correctly sized stainless liner. The band is chimney height and how much of the old flue has to be cleared first.

Fitting the liner

• Four hours, most of it on a roof feeding a liner down a chimney and connecting it at the bottom.

Condensate drain and neutraliserestimated, ±52%

• A condensing furnace makes several litres of water a day in cold weather, and that water is mildly acidic.
• The neutraliser is a small canister of limestone chips in the drain line. It is cheap, it is often skipped, and skipping it is what eats a cast iron waste stack from the inside.

Condensate pumpestimated, ±44%

• Only needed when there is no drain below the furnace for the water to fall into, which is normal in a slab house or an attic.
• It is also a moving part with a float switch, in a job that otherwise has almost none. It is the component most likely to need attention in the first ten years.

Gas connection, shutoff and sediment trapestimated, ±42%

• Flexible connector, a shutoff within reach of the appliance, and the sediment trap — the short capped stub below the tee that catches whatever the pipe sheds before it reaches the burner.
• Reconnecting to the existing gas run. A new run from the meter is not in this figure and is listed as an exclusion.

Propane conversion kit and regulatorestimated, ±49%

• Propane burns at roughly two and a half times the energy density of natural gas per cubic foot, so the burner orifices are physically smaller and the gas pressure is regulated differently. Furnaces ship configured for natural gas and are converted on site.
• The kit is cheap; doing it wrong is not. An unconverted furnace running on propane over-fires, and that is a cracked heat exchanger and a carbon monoxide problem rather than a performance complaint. It is also why this line exists separately instead of being folded into the gas connection.

Fitting the conversion and setting manifold pressure

• An hour and a quarter to change the orifices, fit the regulator spring and set the manifold pressure with a gauge. On propane that last step is the one that matters and it cannot be done by eye.

Gas fitting and leak test

• An hour and a half to break the connection, remake it and pressure-test it. On many jobs the HVAC technician does this work; it is priced at the pipefitting wage because that is the skill being used.

Dedicated circuit, disconnect and service switchestimated, ±44%

• A furnace with a burner draws very little — it is a blower and a control board — so the electrical side of a gas replacement is small.
• The service switch beside the unit is the one thing a technician will check before anything else, because it is what lets the next person work on it safely.

Heavy feeder and breakers for resistance elementsestimated, ±44%

• An electric furnace of this size draws 60 to 100 amps. That is not a circuit, it is a feeder, and it is frequently the largest single load in the house after the range.
• The band assumes the panel has room and capacity. If it does not, the panel upgrade is a separate job of its own and is listed as an exclusion — it is also the most common reason an electric furnace quote comes back much higher than expected.

Electrical connection

• One hour on a gas furnace, five on an electric one. The difference is the whole story of the two appliances: one needs a plug’s worth of power, the other needs its own feeder.

Thermostatestimated, ±75%

• The band runs from a basic programmable to a connected one. Both do the thing that saves money; only one of them needs an account.
• Priced with the fitting time, because the fitting is where the surprise lives: a two-wire thermostat cable cannot run a modern staged furnace, and pulling a new cable is a real job in a finished house.

Thermostat fitting and configuration

• Forty minutes for a basic one, an hour and a half for a connected one that has to be told what equipment it is driving. Getting that configuration wrong is how a two-stage furnace ends up only ever running on high.

Old furnace removal and disposalestimated, ±45%

• Tipping fee and haulage. A furnace is mostly steel, so in many markets the scrap value offsets part of this — which is why the bottom of the band is low.

Start-up, combustion analysis and airflow check

• Two hours to fire it, measure what comes out of the flue with an analyser, set the gas pressure and check the temperature rise across the heat exchanger.
• This is the step that separates an installation from a delivery, and the one most likely to be quietly skipped on a cheap quote. On a fuel-burning appliance it is also the safety check.

Mechanical permit and inspectionestimated, ±60%

• Fees are set by each jurisdiction and there is no national schedule, so this is a band rather than a figure. It is here because leaving it out would make every quote that includes it look expensive.
• Replacing a furnace is permitted work in most of the country. The inspection is also the only independent check that the flue and the gas connection were done correctly.

Not included in this dataset

Oil-fired furnaces

A different appliance with a tank, a filter, a nozzle and its own service regime. Pricing it inside a gas model would produce a number that is wrong in both directions.

Ductwork replacement or redesign

This prices the furnace and the sheet metal immediately around it. If the ducts themselves are undersized or leaking, that is a separate job and often a larger one than the furnace.

A new gas run from the meter

Assumes an existing gas line at the appliance. A new run is priced by distance and by what it passes through, and cannot be estimated without seeing it.

Electrical panel upgrade

The electric furnace figure assumes the panel has both the physical space and the capacity for a 60 to 100 amp feeder. When it does not, that is a job of its own.

Asbestos on old duct joints or flue cement

Houses from before the eighties can have it. It has to be tested rather than disturbed, and abatement is licensed work with its own pricing.

Air conditioning

The evaporator coil sits on top of the furnace and is often replaced at the same time, but it is priced on our air conditioner page, not here.