Furnace replacement is priced by fuel and efficiency tier, not by one average. An electric furnace swap runs $1,900 to $5,600 installed. A standard 80 percent AFUE gas furnace, the most common replacement, lands between $3,200 and $7,800 with a midpoint around $5,200. High-efficiency condensing furnaces at 95 percent AFUE and above run $7,500 to $12,000 because the equipment costs more and the venting changes to PVC with condensate drainage. Oil furnaces span $2,500 to $10,000.
The efficiency decision is a climate decision. In cold regions with high fuel costs, a condensing furnace's 15 to 20 percent fuel savings can justify its premium over a 15 to 20 year life. In mild climates, the standard tier usually wins the math. Either way, capacity should come from a load calculation, not from copying the old furnace's size, because oversized furnaces short cycle and wear out faster.
If your air conditioner is also past 12 to 15 years, price the bundle: replacing the furnace and AC together runs $5,000 to $12,500, averages about $7,500, and saves $500 to $2,000 in combined labor versus two separate projects. It is also the natural moment to compare a heat pump against the pair.
If a technician condemns your furnace for a cracked heat exchanger during a routine visit, ask to see the crack on camera before agreeing to anything. It is a real and serious failure, but it is also the diagnosis most associated with high-pressure replacement sales. A second opinion costs a service call and can save four figures.
Furnace replacement cost by fuel and efficiency
Fuel type and efficiency tier set the budget more than the brand does. Use these installed ranges to identify which scenario fits your home before comparing quotes.
| Furnace type | Typical installed cost | When it applies |
|---|---|---|
| Electric furnace | $1,900 to $5,600 | Homes without gas service or in mild climates; cheapest install, highest operating cost per unit of heat |
| Gas, standard efficiency (80% AFUE) | $3,200 to $7,800 | The most common replacement; reuses existing metal venting in most homes |
| Gas, high efficiency (95%+ AFUE) | $7,500 to $12,000 | Cold climates and high fuel costs; requires PVC venting and condensate drainage |
| Oil furnace | $2,500 to $10,000 | Regions with established oil service; about $5,000 for most replacements |
| Furnace and AC together | $5,000 to $12,500 | Both units past 12 to 15 years; bundling saves $500 to $2,000 in combined labor |
Standard gas equipment runs $2,300 to $3,700 before labor, and high-efficiency two-stage equipment runs $3,350 to $5,800. Ask each contractor to separate equipment, labor, and venting work so quotes are genuinely comparable.
Signs your furnace needs replacement
Furnaces last 15 to 20 years. Age plus any of these symptoms usually tips the decision toward replacement rather than another repair.
A no-heat call on a younger furnace is usually a repair, not a replacement. Igniters, flame sensors, capacitors, and control boards fail long before the furnace itself is done, and each is a routine fix. The repair-versus-replace question is really about age, the heat exchanger, and whether failures are clustering.
What drives furnace replacement cost
Fuel, efficiency tier, capacity, venting, and bundling decisions move the final number more than brand choice does.
Efficiency tier and venting scope
An 80 percent AFUE furnace vents through metal flue pipe, usually reusing what is there. A condensing furnace at 95 percent or higher extracts so much heat that its exhaust is cool and acidic, requiring new PVC venting and a condensate drain. That is why the high-efficiency tier jumps to $7,500 to $12,000 installed rather than just the equipment difference. The fuel savings of 15 to 20 percent pay that back fastest in cold climates.
Capacity and sizing
Furnace capacity should come from a load calculation that accounts for your home's size, insulation, and windows. Contractors who copy the old unit's size often perpetuate an oversizing mistake made decades ago. An oversized furnace heats in short blasts, cycles more, wears parts faster, and leaves rooms uneven. Bigger is not safer; it is just more expensive twice.
The orphaned water heater problem
In many homes, the furnace and water heater share a chimney. When a new furnace vents through the wall in PVC, the water heater is left alone on a flue that is now oversized for it, which can cause condensation damage and draft problems. Code often requires a chimney liner at that point. Ask about this before signing, because it is one of the most common mid-project surprise charges.
Bundling with the air conditioner
The furnace blower moves air for cooling too, and the AC's evaporator coil sits on top of the furnace. Replacing both at once runs $5,000 to $12,500, averages about $7,500, and saves $500 to $2,000 because the crew, sheet metal work, and commissioning happen once. Pairing a new furnace with a 15-year-old coil often forces rework within a few years.
Labor, code items, and timing
HVAC installation labor commonly runs $75 to $100 per hour, and a straightforward swap takes most of a day. Permits, gas line corrections, electrical updates, and duct repairs add scope when present. Timing matters too: a planned replacement in shoulder season gets better pricing and equipment choice than an emergency swap during the first cold week of winter.
When furnace replacement is usually worth completing
Replacement pays off when it resolves a safety issue, ends a repair cycle, or upgrades the system at a natural decision point.
- The heat exchanger is cracked, which is a combustion safety issue with no economical repair on an old unit.
- The furnace is past 15 years and repairs are clustering or a major component has failed.
- You are replacing the AC anyway and the bundle saves combined labor.
- Fuel bills are high and a load calculation supports a right-sized, higher-efficiency unit.
- You are replacing proactively in shoulder season instead of during a mid-winter failure.
When to pause before signing a furnace contract
Some situations call for a repair, a second opinion, or a sharper quote before committing.
- The furnace is under 12 years old and the diagnosis is a single failed component.
- The unit was condemned during a tune-up and you have not seen evidence of the heat exchanger crack.
- The quote copies the old furnace's capacity with no load calculation.
- A high-efficiency model is quoted without itemized venting, condensate, and permit work.
- You heat with oil or electric resistance and nobody has priced a heat pump against the furnace path.
Estimate your furnace replacement cost
Use the calculator as a planning range before requesting quotes. The estimate scales with fuel type, efficiency tier, home size, and how much venting or duct work the project is likely to need.