Central Air Cost Calculator

This central air cost calculator prices adding or replacing central air conditioning in 2026: equipment, labor, ductwork, electrical work, SEER2 tier and line set length.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: Price central air as equipment, install labor and ductwork separately, then divide by tonnage to compare bids. A 3 ton replacement on existing ducts, with a new coil on the furnace and a 25 ft line set, typically runs $5,150 to $10,500 installed, which is $1,717 to $3,500 per ton.

Your measurements

A rectangular volume: length times width times depth.

Conditioned floor areasq ftOnly used to price ductwork, which is quoted per square foot of the area the ducts have to reach. It does not size the equipment.Cooling capacity (tons)One ton is 12,000 BTU per hour. Take it from a Manual J, not from the old nameplate, because pre-2000 systems were routinely a size over.DuctworkA house with no ducts is the expensive case: trunk, branches, boots, registers, returns, plus the soffits or chases to hide them and the drywall and paint after.Indoor equipmentA coil sits on top of an existing furnace. A house with no furnace needs an air handler instead, which is a bigger box with its own blower.Electrical workA replacement usually reuses the whirlpool disconnect and whip. First-time central air needs a new 240 V circuit, and an older 100 A panel often needs room made for it.Efficiency tierScales the equipment only, never the labor. The step from base to variable speed adds about 70 percent to the box and nothing to the install day.Line set lengthftMeasured along the copper from the condenser to the coil, including the rise. The first 25 ft is in the base price and longer runs are billed by the foot.

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Results

Total range: $5,150 to $10,500; 3 tons, or 36,000 BTU per hour at base efficiency, ducts already there and in good shape, coil only
Equipment: $2,600 to $5,200; Condenser plus coil only at 13.4 SEER2 in the North, 14.3 in the South and Southwest. This is the only line a manufacturer promotion or a utility rebate moves
Installation: $2,550 to $5,300; Labor, permit, evacuation to 500 microns, start-up and haul away, plus 25 ft of line set at $350 to $800
Ductwork: Included, nothing to do; Existing ducts reused as they are. Have the static pressure measured before the quote is signed, because a system that cannot move its rated airflow never reaches its rated efficiency
Cost per ton: $1,717 to $3,500 per ton; Divide every bid by its capacity before comparing. Two quotes on different tonnage are not the same job, and neither are two quotes on different duct scope
Planning estimate: Get the model numbers; Typical 2026 US installed ranges, not a quote. Ask for the AHRI certified reference number, the tonnage and the SEER2 on every bid, and confirm the contractor pulls the mechanical and electrical permits

Central Air Cost formula

Equipment = (condenser range x tons / 3 + indoor equipment range) x efficiency multiplier
Line set = $350 to $800 for the first 25 ft + $14 to $28 per foot beyond it
Installation = labor $2,200 to $4,500 + electrical work + line set
Total = Equipment + Installation + Ductwork; Cost per ton = Total / tons

Worked example

A 1,600 sq ft ranch with hot water baseboard heat and no ducts anywhere, getting 2.5 tons of central air at the mid efficiency tier. The job takes a new air handler, a new 240 V circuit and a 40 ft line set. The condenser at 2.5 tons is $1,667 to $3,167 and the air handler is $1,500 to $3,500. The mid tier multiplier of 1.3 takes the equipment to $4,117 to $8,667.

Labor is $2,200 to $4,500, the circuit adds $600 to $1,600, and the line set is $350 to $800 for the first 25 ft plus 15 ft at $14 to $28, so $560 to $1,220. Installation comes to $3,360 to $7,320. The new duct system at $4 to $9 per square foot across 1,600 sq ft is $6,400 to $14,400, more than the equipment at either end. The total lands near $13,877 to $30,387, or $5,551 to $12,155 per ton. Three ductless heads covering the same house typically run $8,400 to $16,000, which is why houses with no ducts usually go ductless.

Quick reference

Typical 2026 US installed cost for central air, base SEER2, coil on an existing furnace, 25 ft line set, rounded to the nearest $50
House area	Capacity	Ductwork	Installed total
1,200 sq ft	2 tons	Reused	$4,500 to $9,250
1,500 sq ft	2.5 tons	Reused	$4,800 to $9,850
2,000 sq ft	3 tons	Reused	$5,150 to $10,500
2,000 sq ft	3 tons	Sealed and repaired	$5,850 to $12,700
2,000 sq ft	3 tons	Replaced	$9,150 to $19,500
2,000 sq ft	3 tons	New, house had none	$13,150 to $28,500
2,500 sq ft	4 tons	Reused	$5,800 to $11,750
3,000 sq ft	5 tons	New, house had none	$18,500 to $40,050

Where central air money goes in 2026

On a straight replacement the equipment is roughly half the bill. A 3 ton condenser with a coil on the existing furnace is about $2,600 to $5,200 of hardware at base efficiency, against $2,550 to $5,300 for labor, permit, evacuation, start-up, haul away and a line set. Efficiency moves only the hardware half, so a step to variable speed adds about 70 percent to one line and nothing to the other. That is why the cost per ton on a high efficiency quote looks so much worse than the SEER2 number suggests.

The duct situation is what actually separates two quotes. Existing ducts in good shape cost nothing. Sealing them with mastic and adding a return is typically $700 to $2,200. Replacing a bad system runs about $2.00 to $4.50 per square foot of conditioned area. Building one into a house that has never had ducts runs $4 to $9 per square foot. That price carries the trunk, the branches, the boots, the registers, the returns, and the soffits or chases that hide them. On a 1,600 square foot house that is $6,400 to $14,400, more than the air conditioner itself. That crossover is the whole argument for ductless: three heads on one outdoor unit typically run $8,400 to $16,000 installed, and the mini split calculator sizes them room by room.

What the 2023 standards and the refrigerant change did to the price

The 2023 federal standards split the country. A new split system air conditioner must reach 13.4 SEER2 in the northern states and 14.3 SEER2 in the South and Southwest. The enforcement differs too. In the South and Southwest the rule applies at installation, so a contractor cannot legally install a below-minimum condenser there even if it is sitting in the warehouse. In the North it applies at manufacture, so remaining stock could still be installed. SEER2 also replaced SEER, measured at 0.5 inches of water column of external static instead of 0.1. That is much closer to real ductwork, and it is why the headline rating dropped about 4.5 percent for the same machine.

Then EPA's Technology Transitions rule under the AIM Act capped refrigerant global warming potential at 700, which took residential equipment built from January 1, 2025 off R-410A and onto R-454B and R-32. Both are A2L, meaning mildly flammable, so the new systems carry refrigerant leak detection, different service fittings and new storage and transport rules for the installer. On a 2026 job the practical effects are concrete. A new outdoor unit will not pair with an old R-410A coil, the line set is usually replaced rather than flushed, and the technician needs A2L training and separate recovery equipment. That platform change reset manufacturer pricing across every tier.

What this calculator leaves out

It prices the cooling system, not the rest of the house. Not included: the Manual J where a contractor bills it separately, a blower door or duct leakage test, or added supply registers. Nor a whole new return path, a filter cabinet, zoning dampers and controls, or a smart thermostat and its C wire. Drywall, trim and paint repair after ducts go into a finished house sit outside it, and that work is often thousands on its own. So do asbestos abatement on old duct tape, a crane on a roof-mounted unit, attic decking and a service platform, a condensate pump, extended labor warranties and maintenance plans. Permit fees are inside the labor range, but they typically run $50 to $250 and some jurisdictions bill mechanical and electrical separately.

Code limits that apply

IRC M1401.1
Equipment installed to the manufacturer's instructions and the terms of its listing
If you miss it: A condenser paired with an uncertified coil loses its rating, its listing and the compressor warranty at the same time
IRC M1401.3
Cooling capacity taken from a Manual J load and selected with Manual S
If you miss it: The permit stalls where the load sheet is required, and the oversized unit that gets installed leaves the house damp
IRC M1411.3
Condensate to an approved point, with a secondary pan or float switch over finished space
If you miss it: A plugged primary drain on an attic coil shows up as a brown ring on a bedroom ceiling months later
IRC M1305.1.3
Attic equipment gets a 30 in passageway, a service platform, a light and a switch
If you miss it: A coil dropped into an attic with no walkway fails the final, and no tech can service it afterward
NEC 440.14
Disconnecting means within sight of and readily accessible from the outdoor unit
If you miss it: Without it the rough electrical fails, and every future service call starts at the basement panel
NEC 440.32
Branch-circuit conductors at 125 percent of the rated-load current of the compressor
If you miss it: Undersized wire to the condenser overheats at the disconnect and the lugs discolor within a season

Provision	Limit	If you miss it
IRC M1401.1	Equipment installed to the manufacturer's instructions and the terms of its listing	A condenser paired with an uncertified coil loses its rating, its listing and the compressor warranty at the same time
IRC M1401.3	Cooling capacity taken from a Manual J load and selected with Manual S	The permit stalls where the load sheet is required, and the oversized unit that gets installed leaves the house damp
IRC M1411.3	Condensate to an approved point, with a secondary pan or float switch over finished space	A plugged primary drain on an attic coil shows up as a brown ring on a bedroom ceiling months later
IRC M1305.1.3	Attic equipment gets a 30 in passageway, a service platform, a light and a switch	A coil dropped into an attic with no walkway fails the final, and no tech can service it afterward
NEC 440.14	Disconnecting means within sight of and readily accessible from the outdoor unit	Without it the rough electrical fails, and every future service call starts at the basement panel
NEC 440.32	Branch-circuit conductors at 125 percent of the rated-load current of the compressor	Undersized wire to the condenser overheats at the disconnect and the lugs discolor within a season

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

A bid with no model numbers. The AHRI certified reference number is what proves the condenser and coil are a rated match.
Reusing an R-410A line set on an R-454B system without a flush and a pressure test. Old oil left in the copper kills the new compressor.
One 20 by 25 filter grille on a 4 ton system. At 400 CFM per ton it needs 1,600 CFM, which is more than that grille passes.
Buying a 17 SEER2 system onto 1990s ductwork. The rating assumes 0.5 in w.c. of static, and old duct routinely measures double.
No plan for the trunk in a house with no ducts. A 20 in trunk needs a soffit or an attic, and a soffit means drywall, trim and paint.
Treating a mid-summer quote as a normal price. Emergency changeouts in July run at the top of every range and skip the load calculation.

Key facts

Since January 1, 2023 a new split system central air conditioner must reach at least 13.4 SEER2 in the northern states and 14.3 SEER2 in the South and Southwest.
In the South and Southwest the efficiency standard is enforced at installation, so a below-minimum condenser cannot legally be installed there, while in the North it is enforced at the point of manufacture.
EPA's Technology Transitions rule caps refrigerant global warming potential at 700 for new residential air conditioners, moving equipment built from January 1, 2025 off R-410A and onto R-454B and R-32.
Retrofitting a duct system into a house that has none typically costs $4 to $9 per square foot of conditioned floor area in 2026.
Central air is designed around 400 CFM of airflow per ton, so a 3 ton system needs about 1,200 CFM through the supply trunk and the return.

Frequently asked questions

How much does it cost to add central air to a house without ducts?

Typically $13,000 to $30,000 for a 2,000 sq ft house, because the duct system alone runs $4 to $9 per square foot and costs more than the equipment. Two or three ductless heads covering the same rooms typically run $8,400 to $16,000 installed.

How much does it cost to replace just the AC unit?

A 3 ton condenser with a new coil on the existing furnace, reusing the ducts and the circuit, typically runs $5,150 to $10,500 installed, or $1,717 to $3,500 per ton. Replacing only the outdoor unit is rarely allowed now, because an R-454B condenser has to be matched to a certified coil.

Is a higher SEER2 worth the money?

It depends on the ducts and the climate. The rating is measured at 0.5 inches of water column of external static, so a variable speed system on high-static 1990s ductwork never delivers its rated efficiency. In a hot climate with sound ducts and high electric rates the step to 16 SEER2 usually pays; in a mild climate it often does not.

Why is my AC quote so much higher than my neighbor's?

Almost always duct scope, then tonnage, then efficiency tier. A quote that includes replacing the ducts carries $4,000 to $9,000 the other one does not. Divide both by tonnage and compare the AHRI reference numbers before deciding either is wrong.

Sources and references

10 CFR 430.32 Energy conservation standards for central air conditioners by region (U.S. Government Publishing Office)
Technology Transitions under the AIM Act, refrigerant GWP limits by sector (U.S. Environmental Protection Agency)
Directory of Certified Product Performance, condenser and coil matched ratings (AHRI)
Chapter 14 Heating and Cooling Equipment and Appliances, 2021 IRC (ICC)

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.