Furnace Replacement Cost

HomeAdvisor puts the average furnace replacement at $4,814, with most homeowners paying $2,823 to $6,897. HomeGuide's range for a standard-efficiency furnace is $3,500 to $7,500+ installed, and up to $11,500 for a high-efficiency unit.

Cost by fuel type

Electric furnaces cost the least to buy and install but the most to run in most areas. Gas furnaces need a gas line and a flue. Switching fuel types on a replacement adds $500 to $2,000+, and a new gas line for a conversion $350 to $2,000 or more (HomeGuide).

Cost by home size

Standard vs high efficiency

Furnace efficiency is measured in AFUE. HomeGuide lists high-efficiency furnaces (90% to 98% AFUE) at $3,800 to $11,500+ installed.

Equipment vs labor

Other costs

Repair or replace?

A cracked heat exchanger or a failed blower motor on an older furnace often tips the balance toward replacement. See heat exchanger replacement cost and furnace repair cost.

Replacing the AC at the same time

If the air conditioner is also near the end of its life, replacing both together saves a second installation visit. Angi puts a furnace and AC together at about $7,500 on average. See HVAC replacement cost.

When it is time to replace a furnace

• Repairs are becoming frequent or expensive.
• The heat exchanger is cracked.
• Some rooms stay cold even with the system running.
• Gas bills keep rising without changes in use.
• The furnace makes new noises or produces visible soot.

Choosing the right furnace

• Efficiency: furnaces are rated by AFUE, the share of fuel turned into heat. Standard models vent through a metal flue, while high-efficiency condensing models vent through plastic pipe and need a condensate drain.
• Stages: single-stage furnaces run at full output only. Two-stage and modulating furnaces adjust their output and run more quietly and evenly.
• Size: a proper load calculation should set the size, not the size of the old unit.

What affects the price

• Efficiency level and staging.
• Brand and warranty terms.
• Venting changes when moving from a standard to a condensing furnace.
• Work on the ductwork, gas line or electrical connections.
• Permit and removal of the old unit.

Replace the AC at the same time?

If the air conditioner is also older, replacing both together lets the contractor match the indoor coil, blower and outdoor unit. It can also save labor compared with two separate jobs.

Questions to ask

1. Will you do a load calculation instead of matching the old size?
2. Does my home need venting or drain changes for this model?
3. What does the warranty cover, and do I need to register the furnace?

In Texas

With mild winters in much of the state, the extra cost of a top-efficiency furnace takes longer to pay back in Texas than in colder places. Many Texas homeowners put more of their budget into the air conditioner, which runs much more of the year.

80% vs. 90%+ efficiency furnaces

A furnace's efficiency is measured by its AFUE rating, which shows how much of the fuel becomes heat in the house. An 80% furnace vents hot exhaust through a metal flue or chimney. A high-efficiency furnace, often rated 90% or higher, captures more heat by condensing the exhaust, which cools it enough to vent through plastic pipe. The high-efficiency furnace needs a condensate drain and new venting, which can add installation cost.

In mild climates, where the furnace runs less, an 80% furnace may make more financial sense. In cold climates, a high-efficiency furnace saves more on fuel.

The orphaned water heater problem

When a home switches from an 80% furnace to a high-efficiency furnace, the furnace no longer uses the chimney. If a gas water heater shares that chimney, it is now "orphaned," venting alone into a chimney sized for two appliances. The water heater's exhaust may cool too much and fail to draft properly, which can cause condensation in the chimney and carbon monoxide problems. A chimney liner sized for the water heater, or a new water heater with its own venting, may be needed. A good installer checks for this.

Single-stage, two-stage and modulating

Single-stage furnaces run at full power whenever they are on.

Two-stage furnaces have a low and a high setting, running longer at the low setting for more even heat.

Modulating furnaces adjust their output in small increments, giving the most even temperatures and the best efficiency, at the highest price.

Two-stage and modulating furnaces often pair with variable-speed blowers, which improve comfort and air filtration.

Sizing

Like air conditioners, furnaces should be sized with a load calculation. An oversized furnace heats quickly and shuts off, causing temperature swings and extra wear. If your home has had insulation or window upgrades, the new furnace may need to be smaller than the old one.

Installation steps

The installer removes the old furnace, sets the new one, connects the gas line, venting, ductwork and electrical, and installs a condensate drain if needed. The system is started, gas pressure and combustion are tested, and airflow is checked. A permit and inspection are usually required.

Get it in writing

Ask for the model number, AFUE rating, venting changes and warranty terms in writing.

How long the furnace should last

A well-maintained furnace can serve for many years. Regular filter changes, annual tune-ups and correct sizing are the biggest factors you control.

Sources

1. HomeAdvisor: How Much Does a Furnace Replacement Cost? (updated Jun 17, 2026)
2. HomeGuide: How Much Does a New Furnace Cost? (Dec 31, 2025)
3. Angi: How Much Does a New Furnace and AC Cost? (updated Jul 9, 2026)