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Furnace replacement cost calculator

Work out what replacing a furnace will really cost, not just the unit price. It adds the installation labor and the extras that a quote can bury, the thermostat, the permit, hauling the old furnace away, and any ductwork or venting the new unit needs, so the number matches the invoice.

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The furnace itself. A higher-efficiency (AFUE) unit costs more up front and less to run. Bigger homes need a bigger, pricier unit.
The crew's labor to remove the old furnace and fit the new one. A straightforward swap is at the low end; a tricky location or a fuel change costs more.
A new thermostat, the permit and inspection, and hauling the old furnace away. Small lines that add up.
New or modified ducts, a new flue or vent, or a gas-line change if the new unit needs it. Zero for a clean like-for-like swap.
Estimated cost
$4,200

Typical range $3,570 – $5,670

  • Furnace unit$2,500
  • Installation labor$1,300
  • Thermostat, permit & removal$400
  • Ductwork or venting$0
  • Total$4,200
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$3,500 to $7,000 is a typical furnace replacement, often higher-efficiency or with some venting work. Get a load calculation, not just a size-match.

What this assumes, and where it could be wrong

Every one of these is a place the number could be off. They are here because you should be able to check our working, not because we are hedging.

THE UNIT IS ABOUT HALF; THE INSTALL AND THE EXTRAS ARE THE REST.
A furnace quote leads with the unit price, but the labor to fit it, the permit and inspection, a new thermostat, hauling the old one away, and any duct or venting work the new unit needs often add up to as much again. The extras are where a low headline quote catches up to a higher all-in one, so compare installed totals, not unit prices

Higher efficiency costs more up front and less to run. A furnace's efficiency is its AFUE rating, and a high-AFUE unit costs more to buy and saves on the gas bill every winter. Whether it pays back depends on your climate and how long you will stay; in a cold region it usually does.

A fuel or venting change is the expensive surprise. Switching from one fuel to another, or a high-efficiency furnace that needs a different flue or a condensate drain, adds real cost the base quote may not include. If the new unit is a different type from the old, ask what venting it needs.

Sizing matters more than brand. A furnace that is too big short-cycles and wears out early; too small never keeps up. A good installer does a load calculation for your home rather than just matching the old unit's size, and that is worth more than the logo on the front.

The defaults are ours and are a starting point. The unit, the labor, and the extras are yours, and the estimate is only as good as a quote that has accounted for the ductwork and venting the new furnace actually needs.

Frequently asked questions

How much does it cost to replace a furnace?
It is the unit plus the installation plus the extras. The furnace itself is often about half the bill, with labor, the permit, a thermostat, removal, and any duct or venting work making up the rest. A straightforward like-for-like swap is at the low end; a higher-efficiency unit or one needing new venting costs more. The calculator adds up your quote.
Why is furnace installation so expensive?
Because it is more than the box. Removing the old furnace, fitting and connecting the new one, pulling a permit and passing inspection, and modifying ducts, venting, or the gas line if needed is skilled work over most of a day. The unit price you see advertised rarely includes all of that, which is why the installed total is higher.
Is a high-efficiency furnace worth the extra cost?
In a cold climate where the furnace runs hard, usually yes: a higher AFUE rating cuts the gas bill every winter and pays back the higher purchase over years. In a mild climate where it runs little, the payback is slower. It also often needs different venting, which adds to the install, so weigh the running-cost saving against the higher all-in price.
Should I replace the furnace and AC together?
Often it makes sense, because they share the blower and the ductwork and the labor overlaps, so doing both at once is cheaper than two separate jobs. If your AC is also near the end of its life, price a full system on the HVAC replacement page. If the AC is healthy, replacing the furnace alone is fine.

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