Furnace and AC Replacement Cost Calculator
Plan your budget before the HVAC contractor visits. This furnace and AC replacement cost calculator estimates the installed price of a gas furnace with central air, central AC only, a furnace only or a heat pump, based on your home size, system size, efficiency level, ductwork and permits.
Your results will appear here.
How to use the furnace and AC replacement cost calculator
- Choose what you are replacing. Replacing a furnace and AC together is common because the indoor coil and outdoor unit should be matched.
- Enter your home size. Use the heated and cooled floor area, not the lot size.
- Pick a system size or let the calculator estimate it. With Estimate from home size, the calculator allows about 600 sq ft per ton of cooling. If you know your current unit’s size, select it instead.
- Select an efficiency level. Higher SEER2 and AFUE ratings cost more upfront but use less energy.
- Add ductwork and permits if your project needs them.
Furnace and AC replacement cost (2026)
The calculator starts from these installed price ranges for standard-efficiency equipment, including labor and removal of the old unit. The AC prices by size come from NearbyHunt’s 2026 HVAC cost guide, and the furnace and heat pump prices from BuildDecide’s 2026 HVAC replacement guide.
| Central AC size | Typical home size | Central AC installed |
|---|---|---|
| 1.5 tons | up to about 1,050 sq ft | $3,500 – $5,500 |
| 2 tons | about 1,050 – 1,350 sq ft | $4,000 – $6,500 |
| 2.5 tons | about 1,350 – 1,650 sq ft | $4,500 – $7,500 |
| 3 tons | about 1,650 – 1,950 sq ft | $5,000 – $9,000 |
| 3.5 tons | about 1,950 – 2,250 sq ft | $5,500 – $10,000 (between the 3- and 4-ton prices) |
| 4 tons | about 2,250 – 2,550 sq ft | $6,000 – $11,000 |
| 5 tons | about 2,550 sq ft and up | $7,000 – $14,000 |
| Other items | Price used by the calculator |
|---|---|
| Gas furnace, installed | $2,500 – $6,000 |
| Furnace + AC together | Both prices added, then about 10% off for a single installation |
| Ducted heat pump system (around 3 tons) | $10,000 – $18,000, scaled by size |
| High efficiency equipment | about 20% more |
| Premium, variable-speed equipment | about 45% more |
| Minor duct repairs and sealing | $500 – $2,000 |
| Full duct replacement | $2,000 – $6,000 |
| Permits | $250 – $400 |
The square-foot ranges for each size are rules of thumb used by this calculator. The efficiency and combined-install adjustments and the permit range are HomeQuantly planning estimates. The right size for your home depends on insulation, windows, climate and layout.
Worked example
A 2,000 sq ft home needs a new gas furnace and central AC at standard efficiency, keeping the existing ducts, with permits.
- Size: 2,000 ÷ 600 = 3.3 tons, rounded to 3.5 tons
- Equipment and labor: ($5,500 + $2,500) × 0.9 = $7,200 low and ($10,000 + $6,000) × 0.9 = $14,400 high
- Permits: $250 to $400
- Total: about $7,450 to $14,800, with a mid-range estimate near $11,100
What changes the price most
- System size. Bigger homes need more cooling and heating capacity. Oversizing is not better: it wastes money and can leave the house humid.
- Efficiency. SEER2 measures cooling efficiency and AFUE measures furnace efficiency. Higher numbers cost more but lower monthly bills.
- Ductwork condition. Leaky or undersized ducts can waste much of what a new system saves. Ask the installer to inspect them.
- Brand and installer. Installation quality matters as much as the equipment. Compare the warranty on both parts and labor.
- Location and season. Labor rates vary by region, and emergency replacements in peak summer or winter often cost more.
Get the size right with a load calculation
The square-foot estimate in this calculator is only a starting point. A good contractor should do a Manual J load calculation that accounts for your insulation, windows, orientation and climate before recommending a size. An AC tonnage calculator can help you check whether a contractor’s suggestion is in a sensible range.
Frequently asked questions
How much does it cost to replace a furnace and AC?
For a typical 2,000 sq ft home with standard-efficiency equipment and permits, this calculator estimates about $7,450 to $14,800 for a gas furnace and central AC together in 2026. Higher efficiency, ductwork and difficult installations raise the price.
Should I replace my furnace and AC at the same time?
If both units are old, replacing them together often saves on labor and makes sure the indoor coil, furnace blower and outdoor unit are matched. If one unit is fairly new, replacing only the failed one can make sense. Ask your contractor about compatibility.
How much does a new central AC unit cost?
For a 2,000 sq ft home that needs about 3.5 tons, this calculator estimates $5,750 to $10,400 installed with permits at standard efficiency. Smaller homes and lower tonnage cost less.
Is a heat pump more expensive than a furnace and AC?
A ducted heat pump system usually costs more upfront than a standard furnace and AC pair, but it heats and cools with one system and can lower energy bills in mild and moderate climates. Rebates and tax credits may reduce the difference, so check current programs.
How many square feet does one ton of AC cool?
A common rule of thumb is about 500 to 700 sq ft per ton, and this calculator uses 600 sq ft per ton. The real number depends on climate and how well the home is insulated, which is why contractors use a Manual J calculation.
Sources and methodology
Planning estimate only. Prices are 2026 national averages compiled by the HomeQuantly Team from the published sources below and last reviewed on November 9, 2026. Your local prices may be higher or lower. Always get written quotes from licensed local contractors.