Gas Furnace: Repair or Replace? (2026 cost comparison)
The rule of thumb, from Consumer Reports: don't spend more than 50% of a comparable new unit on fixing the old one. For a gas furnace, that 50% line is about $1,900–$6,000 — a new unit runs $3,800–$12,000 and typically lasts 15–20 years. If a repair quote lands under that line and the gas furnace is not yet past its expected life, repair usually wins. Reviewed July 2026.
Repair vs. replace, side by side Estimated
| Cost | Estimated range |
|---|---|
| Typical repair (this gas furnace, all faults we price) | $20–$5,000 |
| New gas furnace (unit only) | $3,800–$12,000 |
| The 50% line half a comparable new unit | $1,900–$6,000 |
Repair: min–max of every gas furnace fault we price (sources on each linked problem page) · New unit: Carrier · Lifespan 15–20 years: Carrier, American Standard · 50% rule: Carrier · Reviewed July 2026 · Estimated
Age × repair-cost worksheet Estimated
Find your gas furnace's age down the side and your repair quote across the top. The cell is the way the 50% rule points — Estimated guidance, not advice.
| Age of unit | Repair < 30% of a new gas furnaceunder $1,140–$3,600 | Repair 30–50%$1,140–$3,600 – $1,900–$6,000 | Repair > 50%over $1,900–$6,000 |
|---|---|---|---|
| Under 9 years first half of typical life | Repair likely | Repair likely | Compare quotes |
| 9–20 years second half, under typical lifespan | Repair likely | Compare quotes | Replace likely |
| Over 20 years at or beyond typical lifespan | Compare quotes | Replace likely | Replace likely |
How this is built: we apply the 50% rule (Carrier) — spend no more than half a comparable new unit's cost on a repair — with its lifespan corollary (replacement is favored once the unit is past the midpoint of its expected life and the quote tops 50%). Columns are your repair quote as a share of a new gas furnace ($3,800–$12,000); the $1,900–$6,000 and $1,140–$3,600 thresholds are just 50% and 30% of that range. Rows use the midpoint of the expected life (about 9 years — halfway through a typical 18-year lifespan) and the top of the sourced 15–20 years range (20 years). Nothing here is a per-unit price or a recommendation — it is a transparent reading of the rule.
Carrier's own page separately states installation labor alone runs 'starting at $1,600' inside this bundled range — a floor only, not a sourced labor-only ceiling, so no separate install_delivery_usd range is shown rather than guessing one. Carrier quotes oil furnaces at $6,750–$10,000+ and electric furnaces at roughly $2,000+ on the same page; only the natural-gas figure is carried here since gas is this taxonomy's gas-furnace type.
One more thing before you replace
A newer gas furnace can cut energy and water use, which shifts the math on an older unit even when a repair is cheap: ENERGY STAR notes clothes washers over ~10 years and refrigerators over ~15 years are common efficiency-driven replacements.
Energy note: ENERGY STAR · Reviewed July 2026 · Estimated · Informational only
Price the repair first
Before you decide, get the likely repair figure for the exact fault — each page localizes to your metro:
- Full gas furnace cost guide
- Not heating / blowing cold air
- Won't turn on / no power
- Short cycling (turns on and off)
- Igniter (hot surface ignitor) replacement
- Flame sensor cleaning / replacement
- Blower motor replacement
- Gas valve replacement
- Control board replacement
- Cracked heat exchanger replacement
- Pilot light / thermocouple won't stay lit
- Noisy or loud (banging, rumbling, squealing)
Estimated ranges — see the methodology for how we build the repair figures and their named sources. This page is informational and is not repair, purchasing, or financial advice.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).