Furnace Replacement Cost Calculator

A furnace replacement runs $3,500–$8,500 for a standard gas unit and more for oil or high-efficiency condensing models. This calculator sizes the installed budget and flags where ductwork or fuel switching adds cost.

Furnace size (BTU/hr)

typical 60k–100k for 1500–2500 sq ft

Fuel type

Target efficiency (AFUE %)

Ductwork condition

Region cost factor

Estimated total

$6,250

installed

Low end

$5,313

High end

$7,500

Equipment cost

$3,400

unit only

Ductwork cost

How the math works

Furnace replacement typically runs $3,500–$7,500 installed for a standard gas unit. Higher AFUE (96%+ condensing) models cost more up-front but pay back through energy savings in 4–8 years in most climates.

Add ductwork cost if the existing system is leaking, undersized, or returning air from an unsuitable location. A Manual J load calculation is worth the $200–300 to right-size the new unit.

How to Use

Enter target BTU capacity. 60,000–80,000 BTU covers most 1,500–2,500 sq ft homes in moderate climates; cold climates need more.
Select fuel. Natural gas is cheapest to install and operate; oil requires a tank; electric has no fuel delivery but higher operating cost.
Set target AFUE (annual fuel utilization efficiency). Standard is 80%; condensing is 95%+.
Choose ductwork condition. Replacement can add $3,000–$8,000.
Apply regional cost factor — higher in HCOL metros with union labor.

Frequently Asked Questions

Is a 96% AFUE furnace worth the upgrade?

In colder climates, yes — payback is typically 4–8 years. In moderate climates where heating runs only a few months per year, the savings may not justify the $800–1,500 upgrade cost.

Should I replace just the furnace or the full HVAC?

If the AC is under 10 years old, replace just the furnace. If both are over 12 years and the AC is R-22 refrigerant, replace together for better price and matched efficiency. Use the HVAC calculator for a full system replacement.

Do I need a permit?

Almost always yes — HVAC work involves gas connections (or electrical), and jurisdictions require inspection. Unpermitted work creates insurance and resale problems. Permit cost is usually $100–$400.

Can I go with a heat pump instead?

Heat pumps are increasingly competitive, especially with IRA tax credits. A hybrid heat pump + gas furnace system works well in cold climates. Add $1,500–$3,500 over a straight furnace replacement.