Gas Furnace Replacement Cost Calculator (2026)
Replacing just your gas furnace? This guide provides accurate cost estimates for furnace-only replacement, separate from air conditioner or full HVAC system costs.
Quick Answer
Gas furnace replacement costs $3,000 to $8,000 installed for furnace only. If you also need a matching air conditioner or evaporator coil, add $4,000-$8,000.
| Efficiency Level | AFUE Rating | Installed Cost Range | Annual Savings vs 80% |
|---|---|---|---|
| Standard | 80% | $3,000 - $5,000 | Baseline |
| High efficiency | 95% | $4,000 - $6,500 | $150 - $400/year |
| Premium | 97-98% | $5,500 - $8,000 | $200 - $500/year |
Cost Factors for Gas Furnaces
Efficiency tier (AFUE - Annual Fuel Utilization Efficiency):
- 80% AFUE: Minimum standard, good for mild climates
- 90-95% AFUE: High efficiency, best for cold climates
- 97-98% AFUE: Premium efficiency, maximum savings in severe winters
Heating capacity (BTU output):
- 40,000-60,000 BTU (small home/warm climate): $2,800 - $4,500
- 60,000-80,000 BTU (1,500-2,200 sq ft): $3,200 - $5,500
- 80,000-100,000 BTU (2,000-3,000 sq ft): $3,800 - $6,500
- 100,000-120,000 BTU (large home/cold climate): $4,500 - $8,000
Brand tier:
- Budget brands: Base pricing
- Mid-tier brands (Carrier, Trane, Rheem): +15% to +25%
- Premium brands (American Standard, Lennox): +25% to +40%
When Furnace-Only Replacement Makes Sense
Replace just the furnace when:
- Your AC is under 10 years old and working well
- Furnace heat exchanger is cracked or failing
- Furnace is 15-20+ years old (near end of lifespan)
- AC was recently replaced and is compatible
Replace full system (furnace + AC) when:
- Both systems are 12+ years old
- Replacing with mismatched brands/efficiency levels
- Wanting to upgrade to heat pump or dual fuel
Cost Breakdown
| Component | Cost Range |
|---|---|
| Furnace equipment | $1,500 - $4,500 |
| Installation labor | $1,200 - $2,500 |
| Permits and inspection | $100 - $300 |
| Venting modifications | $200 - $800 (if needed) |
| Thermostat upgrade | $150 - $400 (if needed) |
Decision Framework
Choose high-efficiency (95%+ AFUE) if: you live in a cold climate (5,000+ heating degree days), plan to stay 7+ years, or local gas rates are above $1.20/therm. Payback is typically 5-8 years.
Choose standard efficiency (80% AFUE) if: you live in a mild climate, plan to move within 5 years, or have limited upfront budget.
FAQ
Is this an exact quote?
No. It is a planning estimate. Final pricing depends on contractor scope, brand selection, and installation complexity.
Can tax credits apply to furnace replacement?
Yes. High-efficiency furnaces (95%+ AFUE) may qualify for federal tax credits up to $600 and local utility rebates.
Should I replace my AC at the same time?
If your AC is 10+ years old, bundling can save 10-15% on total project cost versus separate installations.