Cost by furnace type
| Type | Typical installed US cost |
|---|---|
| 80% AFUE gas, single-stage | $3,000–$5,000 |
| 95–97% AFUE gas, two-stage | $4,500–$7,500 |
| Modulating, variable-speed gas | $6,000–$10,000+ |
| Electric furnace | $2,000–$5,000 |
| Propane furnace | Similar to gas, plus conversion kit if needed |
AFUE efficiency
AFUE is the share of fuel that becomes useful heat. An 80% furnace vents hot gases through a metal flue, while a 95%+ condensing furnace uses PVC venting and a condensate drain. Switching from 80% to 95% may require new venting, which is easy in some homes and costly in others.
Extra costs
- New venting or chimney liner: $500–$2,500
- Gas line modifications: $250–$1,000
- Condensate pump: $150–$400
- Ductwork changes: varies widely
Signs it's time to replace
- Age 15–20+ years with frequent repairs
- Cracked heat exchanger
- Rising gas bills and uneven heating
- Yellow or flickering burner flames, or soot
Frequently asked questions
Should I switch to a heat pump instead?
It depends on climate, fuel prices and ductwork. Many homes in cold climates choose dual fuel. See our heat pump vs. furnace guide.
