How the estimate is built
HVAC prices published online disagree, sometimes by thousands of dollars, because they come from different places. Cost sites like HomeGuide average the quotes homeowners report, which include independent contractors and value brands. Manufacturers like Trane publish what their dealers charge for their own lines. Neither is wrong, so the calculator uses both: the low end of each range is the lower of the two typical prices, the high end is the higher, and the headline is the midpoint. Here is the math with the values the calculator opens with: a standard 3-ton central AC and an 80,000 BTU, 96% gas furnace replaced together, ducts reused, typical access, U.S. average.
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1
Price the AC
HomeGuide's typical 3-ton installed AC is $4,750; Trane's single-stage line averages $7,556. That gives a range of $4,750 to $7,556 for the AC.
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2
Price the furnace and scale it to size
A condensing furnace runs $6,788 (Trane, 96% single-stage) to $7,000 (HomeGuide, 90–95% models). An 80,000 BTU furnace sits about 10% above the middle of HomeGuide's size table, so ×1.1: $7,467 to $7,700.
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3
Take off the shared labor
Replacing both in one visit saves a second trip, a second setup and duplicate startup work. The calculator takes off $1,000, a HomeOutlay estimate at the low end of HomeGuide's $1,000 to $3,000 labor range for one install.
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4
Add the job and the extras
The permit adds $100 to $250. The total comes to $11,317 to $14,506, with a typical price of $12,911. Then the calculator adjusts for your state's HVAC wages, the access and the ductwork you pick.
Installed prices by equipment and tier
National typical prices for a 3-ton system and a 60,000 to 80,000 BTU furnace, existing ducts, with installation and removal of the old unit. Standard is single-stage, mid is two-stage, high is variable-speed or modulating.
| Equipment | Standard | Mid | High |
|---|---|---|---|
| Central AC and coil | $4,750–$7,556 | $6,100–$9,622 | $8,250–$12,597 |
| Gas furnace, 80% AFUE | $5,000–$5,287 | $5,000–$5,732 | $5,000–$6,193 |
| Gas furnace, 96% AFUE | $6,788–$7,000 | $7,000–$7,132 | $7,980–$9,750 |
| Heat pump and air handler | $9,000–$15,064 | $11,500–$18,487 | $14,500–$22,118 |
| Heat pump only (dual fuel) | $6,000–$9,301 | $8,500–$11,285 | $11,500–$14,193 |
A heat pump system here means the outdoor heat pump plus a new indoor air handler. "Heat pump only" swaps the outdoor unit and coil and keeps your furnace as backup, which is how a dual-fuel system is built.
Cost by size
Bigger equipment costs more, but not in proportion: much of the price is labor, refrigerant work and the visit itself. These factors come from HomeGuide's installed price per size.
| AC size | BTU/h | Size factor | Standard AC, typical |
|---|---|---|---|
| 1.5 tons | 18,000 | ×0.74 | $3,501–$5,569 |
| 2 tons | 24,000 | ×0.84 | $4,000–$6,362 |
| 2.5 tons | 30,000 | ×0.92 | $4,351–$6,921 |
| 3 tons | 36,000 | ×1.00 | $4,750–$7,556 |
| 3.5 tons | 42,000 | ×1.06 | $5,049–$8,032 |
| 4 tons | 48,000 | ×1.16 | $5,501–$8,750 |
| 5 tons | 60,000 | ×1.26 | $5,999–$9,543 |
Don't buy by the old unit's label. Many systems were oversized from the start, and new windows or insulation lower the load. A contractor should run an ACCA Manual J load calculation, which most codes require, before quoting. Our AC size calculator and furnace size calculator give you a number to check the quote against.
Efficiency: SEER2 minimums and what upgrading saves
Since January 1, 2023, the Department of Energy sets minimums in SEER2, a stricter test than the old SEER. A split-system AC must reach 13.4 SEER2 in the North. In the Southeast and Southwest it must reach 14.3 SEER2 below 45,000 BTU per hour and 13.8 above, and in the Southwest it must also meet an EER2 minimum. Split heat pumps must reach 14.3 SEER2 and 7.5 HSPF2 everywhere. The data plate above shows the minimum for the state you pick.
Is a higher tier worth it? Take a 3-ton AC in a mixed climate that runs about 1,000 full-load hours a year, the figure our AC size calculator uses for zone 4. At 14.3 SEER2 it uses 2,517 kWh; at 17 SEER2, 2,118 kWh. The 399 kWh difference is about $73 a year at 18.2 cents. The mid tier costs about $1,700 more here, so payback on energy alone is over 20 years. In Texas, Florida or Arizona, with two to three times the cooling hours, the same upgrade pays back two to three times faster. Two-stage and variable-speed units also run quieter and pull more humidity out, which some people value more than the savings.
Ductwork
A straight change-out on good ducts usually takes a day. Ducts that leak, are crushed, are uninsulated in an attic or are too small for the new equipment can cancel out the efficiency you just paid for. HomeGuide puts manual duct sealing at $400 to $1,900, duct replacement at $1,400 to $5,600 for most homes, and new ductwork in a house without it at $2,400 to $6,600. The calculator scales those by system size. Ask the contractor to measure static pressure and look at the ducts before quoting; it's a quick test that tells you whether they're the problem.
Tax credits and rebates in 2026
The federal credits are over. The Energy Efficient Home Improvement Credit (25C) paid 30% of the cost, up to $600 for a qualifying central AC, gas furnace or boiler and up to $2,000 a year for a heat pump. The 2025 budget law ended it early, and the IRS says it applies to property placed in service through December 31, 2025. The Residential Clean Energy Credit (25D), which covered geothermal heat pumps, is not available for property placed in service after December 31, 2025, either. A system installed in 2026 gets neither, even if you signed the contract last year.
What's left: utility rebates, which vary widely; state programs; manufacturer and dealer promotions; and, for low- and moderate-income households, the state-run federal rebate now called the High-Efficiency Electric Home Rebate, which since mid-2026 no longer pays to replace gas, propane or oil equipment. Look up your ZIP code in the ENERGY STAR rebate finder or DSIRE and type what you qualify for into the rebates box.
The refrigerant change
New residential split systems stopped being made with R-410A on January 1, 2025, under the EPA's Technology Transitions rule. New units use A2L refrigerants, mostly R-454B or R-32, with new coils, sensors and line-set practices. In May 2026 the EPA removed the deadline for installing R-410A equipment built before 2025, so leftover stock can still go in, though New York kept its own January 1, 2026 cutoff. Either way, an outdoor unit and indoor coil must use the same refrigerant, so replacing just the outdoor half of an R-410A system with an A2L unit isn't an option.
Repair or replace?
- The $5,000 rule: multiply the repair quote by the system's age. Over $5,000, replacing usually makes more sense (HomeGuide's rule of thumb).
- The 50% rule: if a repair costs at least half the price of a new system, replacing usually wins, especially once the system is past 10 years.
- Lifespans: HomeGuide cites 15 to 20 years for an AC, 10 to 20 for a heat pump and 15 to 30 for a furnace.
- Safety: a cracked heat exchanger, a gas smell or a carbon monoxide alarm means shut the furnace off and call a licensed technician now, not a price comparison.
Getting a fair quote
- Get at least three written quotes for the same size, tier and scope. Check that each names the model numbers of both the outdoor unit and the indoor coil or air handler, and lists the AHRI matched rating.
- Ask whether the price includes the permit, a new line set, a pad, thermostat, condensate pump, electrical work and haul-away of the old unit.
- Spring and fall are the slow seasons, when contractors have the most room on price and schedule.
- Gas, refrigerant and 240-volt electrical work need licensed pros and, in most places, a permit and inspection. That protects you and the warranty.
- If you're weighing a heat pump against a new furnace, price the running cost too with our heating cost calculator and heat pump savings calculator.
Common questions
How much does it cost to replace an HVAC system in 2026?
A standard 3-ton central AC and a 96% gas furnace replaced together typically cost about $11,000 to $15,000 installed, using the existing ducts. A heat pump with a new air handler runs about $9,000 to $15,000 for an entry model and more for two-stage or variable-speed units. New ductwork, an electrical upgrade or a hard install adds to that.
How much does a new central air conditioner cost?
A 3-ton single-stage central AC typically costs about $4,750 to $7,550 installed in 2026, based on HomeGuide's reported quotes and Trane's 2026 price guide. Two-stage models run about $6,100 to $9,600 and variable-speed models about $8,250 to $12,600. Smaller units cost less and 5-ton units about a quarter more.
Is there a federal tax credit for a new AC, furnace or heat pump in 2026?
No. The Energy Efficient Home Improvement Credit (section 25C), which paid up to $600 for a central AC or furnace and up to $2,000 for a heat pump, applies only to equipment placed in service by December 31, 2025. The credit for geothermal heat pumps also ended after 2025. Utility and state rebates may still apply.
Should I replace my furnace and AC at the same time?
Often yes if both are over about 15 years old. One crew visit saves labor, and a matched indoor coil and blower let a new AC reach its rated SEER2. If the furnace is newer and healthy, replacing only the AC and coil is reasonable.
What SEER2 rating is required for a new AC?
Since 2023, a new split-system central AC must be at least 13.4 SEER2 in the North and 14.3 SEER2 in the Southeast and Southwest for units under 45,000 BTU per hour (13.8 for larger ones). Split-system heat pumps must be at least 14.3 SEER2 and 7.5 HSPF2 everywhere.
Does a new HVAC system need new ductwork?
Not always. Sound, sealed ducts that are the right size can be reused, which keeps a replacement to about one day. Ducts that leak, are crushed or are undersized for the new equipment should be repaired or replaced; HomeGuide puts duct replacement at about $1,400 to $5,600 for most homes.
Sources and assumptions
- Dealer prices: Trane 2026 HVAC Replacement Cost Guide, national installed ranges by line (Choice single-stage, Priority two-stage, Premier variable-speed), checked November 2026. The calculator uses the midpoint of each range; a heat pump system adds Trane's air handler range.
- Reported quotes: HomeGuide, HVAC cost (AC by tons, SEER price steps, labor, permits, zoning, thermostat; August 2025), gas furnace prices (by AFUE and size; December 2025), heat pump cost (by SEER2/HSPF2, panel upgrade, line sets, pads; October 2025) and ductwork (December 2025). The calculator uses the midpoint of each range. The AC mid and high tiers add HomeGuide's unit price step from 13–14 SEER to 17–18 and 22–26 SEER to its 3-ton installed price.
- Regional labor: U.S. Bureau of Labor Statistics, Occupational Employment and Wages, HVAC mechanics and installers (49-9021), mean hourly wage by state, May 2025 (U.S. $31.14). The calculator assumes labor is about 30% of an installed price (a HomeOutlay estimate from HomeGuide's unit and labor split) and moves that share with your state's wage.
- Efficiency minimums: furnaces, 80% AFUE for non-weatherized gas models (10 CFR 430.32(e)); air conditioners and heat pumps, DOE, 2023 Central Air Conditioner and Heat Pump Standards FAQ, including the Southeast and Southwest state lists.
- Tax credits: IRS, Energy Efficient Home Improvement Credit (updated April 28, 2026) and Residential Clean Energy Credit (updated July 4, 2026). Rebate rules: DOE Home Energy Rebates Program Notice 26-2. Rebate lookup: ENERGY STAR rebate finder and DSIRE.
- Refrigerant: ACHR News, EPA removes R-410A installation deadline (May 2026), on the EPA Technology Transitions rule.
- HomeOutlay assumptions: size factors from HomeGuide's installed price by tons (1.5 tons ×0.74 to 5 tons ×1.26) and by furnace size relative to the 60,000–80,000 BTU middle (40k ×0.79 to 120k ×1.34); $1,000 off when an AC and furnace are replaced together; access ×0.95 easy, ×1.15 hard on the equipment; ducts priced per ton of cooling ($700–$1,500 to replace, $900–$1,940 for new, $400–$1,900 flat to seal), with a furnace-only job counted as one ton per 24,000 BTU of input. All of these are estimates; every number on a quote beats them.