Repair vs replace

Should you repair or replace a furnace?

Use this calculator with typical furnace repair and replacement ranges. Adjust the defaults to match your quote before deciding.

Reviewed by the Fix or Keep editorial team · Updated September 18, 2026

Typical repair range

$180-$1,200

Planning midpoint: $690

Typical replacement range

$4,500-$9,500

Planning midpoint: $7,000

Expected life

18 years

A planning average, not a failure date

Typical furnace repair range: $180- $1,200. Expected lifespan: 18 years.

How to judge the diagnosis

Ignitors, flame sensors, and some blower components are often repairable. A damaged heat exchanger, repeated safety lockouts, or several major failures on an older furnace deserve a replacement comparison.

Use the calculator's ratio as a starting point, then test the assumptions. A lower repair price is more persuasive when the failed part is confirmed, the rest of the furnace is in good condition, and the repair carries a useful warranty.

What replacement pricing should include

Replacement pricing may include venting, gas or electrical work, sheet-metal transitions, permits, thermostat changes, startup testing, and removal of the existing furnace.

Compare written, all-in totals. A sale price can look favorable until required accessories, installation, disposal, or work on connected systems is added.

Common failures

  • Ignitor
  • Flame sensor
  • Blower motor
  • Heat exchanger

Repair signals

  • Ignitor or flame sensor issue
  • Heat exchanger is sound
  • Unit is under 12 years

Replace signals

  • Cracked heat exchanger
  • Frequent safety lockouts
  • Very old low-efficiency unit

Safety comes before the calculation

Stop using the furnace and seek qualified help for a carbon-monoxide alarm, gas smell, soot, rollout, repeated safety trips, or a suspected heat-exchanger problem.

Efficiency and operating cost

Fuel price, climate, duct condition, equipment sizing, and blower electricity all affect savings. Comfort and safety can matter more than a simple fuel-payback calculation.

Treat projected savings as a range. Utility rates, usage, weather, maintenance, sizing, and installation quality can matter as much as the efficiency rating printed on the product.

Questions to ask before approving work

  1. 1. Was the heat exchanger visually and instrumentally checked?
  2. 2. What caused the safety lockout?
  3. 3. Is venting compliant with the proposed equipment?
  4. 4. What labor and parts warranties are included?

Frequently asked questions

Is it worth repairing a furnace?

Repair is usually easier to justify when the failed part is confirmed, the total is comfortably below replacement, and the item has meaningful expected life left. Use your written quote rather than the default range.

When should I replace a furnace?

Replacement deserves a closer look when several major failures are likely, parts are unavailable, safety or reliability is compromised, or the all-in repair cost approaches a properly calculated replacement total.

Does the 50% rule always work?

No. A cost ratio is useful, but age, condition, warranty, installation cost, reliability, and the consequence of another failure can change the answer substantially.

How accurate are these cost ranges?

They are broad planning ranges. Model, location, labor rates, access, permits, parts, and the exact diagnosis can move a real quote outside the range.

Sources and scope

Planning guidance is informed by manufacturer service information and public resources from U.S. Department of Energy Energy Saver, ENERGY STAR, and the U.S. Consumer Product Safety Commission recall database. Cost figures are estimates, not quotes. See the calculator methodology.