Furnace Replacement Cost (2026): $3,500–$10,000

A gas furnace replacement costs $3,500 to $10,000 installed in 2026, with most homeowners around $5,500 to $7,500. Efficiency rating, furnace size, and how much of the existing venting and ductwork can be reused drive the number.

Cost breakdown

• Standard-efficiency (80% AFUE), like-for-like swap: $3,500-$6,000.
• High-efficiency (95%+ AFUE) condensing furnace: $5,500-$10,000.
• Upsizing / new gas or electrical line: add $500-$2,000.
• New venting (condensing furnaces need PVC): add $500-$1,500.
• Duct modifications or a new return: add $1,000-$3,000.
• Permit and inspection: $100-$400 depending on jurisdiction.

What actually drives the price

Furnace capacity (BTU), efficiency tier, and brand set the equipment cost. Installation cost swings on whether it's a straight swap or involves new gas piping, a condensate drain, new PVC venting for a condensing unit, electrical work, or duct and return modifications. Attic or crawlspace installs cost more than a basement. Regional labor rates and permit fees vary widely.

Confirm what carries over before quoting

A furnace quote is really a question of how much of the existing system survives. Same size, same efficiency class, reusable venting and ducts is the cheap case. A photo of the current unit's data plate, the venting, and the surrounding space tells you which case you're in before the truck rolls.

What to ask for in furnace photos

Ask for a photo of the current furnace data plate (model, BTU and age), the venting where it leaves the unit and the house, the gas line and shutoff, the return air and filter slot, the thermostat, and the space around the unit with clearances. Ask whether the water heater shares the flue and whether there's AC on top. That tells you whether it's a swap or a venting job, and Fast Snap Pro drafts good/better options from your own equipment and labor prices. See also the HVAC installation cost guide and HVAC service call pricing.

Example: 80% to 96% AFUE upgrade

Line item	How it's priced	Example
96% AFUE, 80,000 BTU furnace	Equipment	$3,400
Labor: remove old, set new, start-up	Flat	$1,800
New PVC intake and exhaust venting	Flat	$850
Condensate drain and pump	Flat	$250
Abandon or line old chimney flue (water heater)	Flat	$600
Permit	Pass-through	$200
Total		$7,100

Illustrative numbers only.

Moving from 80% to a condensing furnace almost always adds venting, a condensate line and sometimes a chimney liner for the water heater left behind. Offering a like-for-like 80% option beside it is a natural good/better choice.

Frequently asked questions

How much does it cost to replace a furnace in 2026?

$3,500 to $10,000 installed, typically $5,500 to $7,500. High-efficiency condensing furnaces are at the upper end.

Is a high-efficiency furnace worth the extra cost?

In colder climates with high gas use, the fuel savings can pay back the difference over the unit's life; in mild climates the payback is slower.

What makes furnace replacement more expensive?

Switching to a condensing furnace (new PVC venting and a condensate drain), upsizing, new gas or electrical runs, duct modifications, and difficult install locations.

Can furnace replacement be quoted from photos?

A starting range can, from photos of the existing unit's data plate, the venting, and the install area. A load calculation and site visit are needed before a firm quote.

How long does a furnace replacement take?

A straightforward swap usually takes 4 to 8 hours. Conversions to a condensing furnace with new venting or duct changes can take a full day or more.

Should I replace the AC at the same time as the furnace?

If the AC is old or uses phased-out refrigerant, replacing both together can save labor and ensure matched equipment. If the AC is newer, replacing only the furnace is common.

Give faster ballpark numbers

Try Fast Snap Pro to turn customer photos into a starting price range built on your own rates, before you schedule the in-person walkthrough.