HVAC Cost Calculator
Price an HVAC replacement: this HVAC cost calculator splits equipment from installation by system type, tonnage, efficiency tier, ductwork and gas or electrical work.
By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.
Results
- Total range
- $8,400 to $16,900
- 3 tons, or 36,000 BTU per hour, base efficiency, reuse the existing ducts
- Equipment
- $4,200 to $8,300
- Furnace and AC at 13.4 to 14.3 SEER2 or 80% AFUE, the federal minimum since January 1, 2023. This is the line a rebate or a manufacturer promotion moves
- Installation
- $4,200 to $8,600
- Labor, permit, start-up and haul away, and new line set and pad at $400 to $900
- Cost per ton
- $2,800 to $5,633 per ton
- Divide any bid by its capacity before comparing it. Two quotes on different tonnage are not the same job
- Planning estimate
- Get a Manual J
- IRC M1401.3 requires equipment sized from an ACCA Manual J load calculation, not from square feet or the old nameplate. A licensed mechanical contractor and the local permit govern the install
HVAC Cost formula
Equipment = base equipment range x (tons / 3) x efficiency multiplier
Installation = base labor range x access multiplier + ductwork + gas or electrical + line set and thermostat
Total = Equipment + Installation
Cost per ton = Total / tons (mini splits: outdoor unit + per head equipment and labor)Worked example
A 4 ton high efficiency heat pump replacing a failed system in an attic. The job includes full duct replacement, a new 240 V circuit, and a new line set, pad and smart thermostat. The heat pump equipment base is $3,800 to $8,000 at 3 tons, so at 4 tons it is $5,067 to $10,667. The high efficiency multiplier of 1.6 takes that to $8,107 to $17,067.
Labor starts at $3,200 to $7,000, and the attic multiplier of 1.15 makes it $3,680 to $8,050. Ducts add $3,000 to $9,000, the circuit adds $600 to $2,500, and the line set package adds $600 to $1,400, so installation is $7,880 to $20,950. The total lands near $15,990 to $38,020, about $4,000 to $9,500 per ton. Ductwork alone is a fifth to a quarter of it, which is why a duct quote has to be itemized.
Quick reference
| System | Capacity | Installed total |
|---|---|---|
| Gas furnace only | 3 ton house | $3,500 to $7,000 |
| Air conditioner only | 3 tons | $4,500 to $9,000 |
| Furnace and air conditioner | 3 tons | $8,000 to $16,000 |
| Furnace and air conditioner | 4 tons | $9,400 to $18,767 |
| Air source heat pump | 3 tons | $7,000 to $15,000 |
| Air source heat pump | 4 tons | $8,267 to $17,667 |
| Dual fuel, heat pump and furnace | 3 tons | $10,000 to $20,000 |
| Packaged unit | 3 tons | $6,500 to $13,000 |
| Ductless mini split | 1 head | $3,600 to $6,800 |
| Ductless mini split | 3 heads | $8,400 to $16,000 |
Where the money actually goes
On a straight changeout the box is roughly half the bill. A 3 ton furnace and air conditioner at base efficiency is about $4,200 to $8,300 of equipment and about $3,800 to $7,700 of labor, permit, start-up and disposal. Efficiency moves only the equipment half, so stepping from base to a variable speed system adds about 60 percent to one line and nothing to the other. That is why the per-ton figure on a high efficiency quote looks so much worse than the headline SEER2 number suggests.
Ductwork is the line that makes two quotes look incompatible. Sealing and repairing existing trunk and branch runs is typically $600 to $2,000. A full replacement in a 1,500 to 2,500 square foot house is typically $3,000 to $9,000. Ask every bidder to itemize it. A contractor who measured static pressure and found 0.9 inches of water column on a system designed for 0.5 is pricing a different job. It is usually the correct one.
What changed in 2023 and 2025, and why 2026 prices moved
Two federal changes landed back to back. On January 1, 2023 the minimum efficiency rose and the test method changed to SEER2. SEER2 is measured at 0.5 inches of water column of external static instead of 0.1, which is closer to real ductwork. Split system air conditioners now start at 13.4 SEER2 in the North and 14.3 SEER2 in the South and Southwest. Split heat pumps start at 14.3 SEER2 with 7.5 HSPF2 nationally. Gas furnaces still start at 80% AFUE, and that minimum goes to 95% AFUE for units manufactured on or after December 18, 2028.
Then EPA's Technology Transitions rule under the AIM Act capped refrigerant global warming potential at 700 for new residential air conditioners and heat pumps. That pushed the industry off R-410A and onto A2L refrigerants such as R-454B and R-32. A2L means mildly flammable, so the new equipment carries leak detection, different service fittings and new storage and handling rules. The transition reset manufacturer pricing across the board. On a 2026 job the practical consequences are concrete. A new outdoor unit will not pair with an old R-410A coil, and the line set is usually replaced rather than flushed. The servicing technician also needs A2L training and the right recovery gear.
What this calculator leaves out
This prices equipment and installation, not the building. It does not include a Manual J load calculation where a contractor bills for it separately, an energy audit or a blower door test. Added supply or return registers, a new return path, a filter cabinet, and zoning dampers and controls all sit outside it. So does a chimney liner, which an 80 percent furnace replaced by a 95 percent unit often forces when the water heater is left orphaned in the flue. It also leaves out asbestos abatement on old duct tape and boiler jackets, drywall and paint repair after duct work, and a condensate pump and neutralizer. Crane or roof work on a packaged unit, extended labor warranties and annual maintenance plans are not in it either. Permit fees are inside the labor range here, but they run typically $50 to $250 and some jurisdictions bill mechanical, gas and electrical separately.
Code limits that apply
- IRC M1401.3
Equipment sized from an ACCA Manual J load calculation and selected by Manual S
If you miss it: An oversized system short-cycles, never pulls humidity down, and the permit stalls where the load sheet is required
- IRC M1305.1.1
30 in deep by 30 in wide level working space at the service side of the appliance
If you miss it: A furnace boxed into a closet fails inspection and the wall has to be opened back up
- IRC M1601.4.1checked
Duct joints, seams and connections sealed with mastic, mastic tape or a listed tape
If you miss it: Cloth duct tape dries out within a few years and the system loses a fifth of its air into the attic
- IRC M1411.3
Condensate drained to an approved point, with a secondary pan or switch over a finished space
If you miss it: A blocked primary drain over a bedroom ceiling turns into a drywall claim before anyone notices
- NEC 440.14
Disconnecting means within sight of and readily accessible from the outdoor unit
If you miss it: No disconnect at the condenser means the service tech has to kill the panel, and the rough electrical fails
- NEC 440.22
Branch-circuit protection no larger than the maximum size marked on the equipment nameplate
If you miss it: An oversized breaker on the condenser voids the listing and is written up at the electrical final
Rows marked checked produce a warning in the results when an entry crosses the limit. The others are on the plans or on site and this calculator does not test them. Local amendments can be stricter; the adopted edition and the inspector govern.
Mistakes that cost money
- Sizing from square feet or the old nameplate. IRC M1401.3 wants a Manual J, and the old unit was often oversized to begin with.
- Pairing a new R-454B condenser with the old R-410A indoor coil. The AHRI certified match is what the warranty and the rating depend on.
- Reusing a line set without flushing and pressure testing it. Old oil left in the copper contaminates the new compressor.
- No condensate plan on a 95% AFUE furnace. It makes several gallons a day and needs a trapped drain, and often a pump and neutralizer.
- Storage stacked against the service side. IRC M1305.1.1 wants 30 in by 30 in of level working space or the inspector will not sign off.
- Taking a bid with no tonnage or model number on it. Without both, the per-ton price cannot be compared to anything.
Key facts
- Since January 1, 2023 the federal minimum for a split system central air conditioner is 13.4 SEER2 in the North and 14.3 SEER2 in the South and Southwest.
- Split system heat pumps carry a national minimum of 14.3 SEER2 and 7.5 HSPF2 under the 2023 standards.
- The federal minimum for a non-weatherized gas furnace is 80% AFUE, rising to 95% AFUE for units manufactured on or after December 18, 2028.
- EPA's Technology Transitions rule caps refrigerant global warming potential at 700 in new residential air conditioners and heat pumps, which moved new equipment from R-410A to R-454B and R-32.
- One ton of cooling is 12,000 BTU per hour, so a 3 ton system is rated at 36,000 BTU per hour.
Frequently asked questions
How much does it cost to replace an HVAC system?
A 3 ton gas furnace and air conditioner at base efficiency, reusing existing ducts with a new line set and pad, typically runs $8,400 to $16,900. That is $2,800 to $5,633 per ton. High efficiency equipment and full duct replacement can double it.
Why did HVAC prices rise in 2025 and 2026?
EPA's Technology Transitions rule capped refrigerant global warming potential at 700 for new residential systems, so manufacturers moved from R-410A to A2L refrigerants such as R-454B. New equipment platforms, leak detection and A2L handling reset prices industry wide.
Do I need new ductwork with a new furnace?
Not always, but it has to be measured. Ducts sized for an older blower often run too much static pressure for a modern variable speed air handler. Sealing and repair is typically $600 to $2,000; full replacement in a 1,500 to 2,500 sq ft house is typically $3,000 to $9,000.
Is a heat pump cheaper than a furnace and an air conditioner?
The install is usually similar, at roughly $7,000 to $15,000 for a 3 ton heat pump against $8,000 to $16,000 for a furnace and AC pair. The difference shows up in the operating cost, which depends on local gas and electric rates and on the winter design temperature.
Sources and references
- 10 CFR 430.32 Energy and water conservation standards for central air conditioners, heat pumps and furnaces (U.S. Government Publishing Office)
- Technology Transitions under the AIM Act, HFC restrictions by sector (U.S. Environmental Protection Agency)
- Chapter 14 Heating and Cooling Equipment and Appliances, 2021 IRC (ICC)
- Manual S Residential Equipment Selection (ACCA)
Next steps for this project
The usual order for a insulation & hvac project. See all insulation & hvac calculators.
Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.