Three contractors can quote the same house thousands of dollars apart, and it's hard to tell whether the cheap quote cuts corners or the expensive one pads the bill. The difference usually comes down to scope: what equipment, what efficiency, whether the ducts and wiring are touched, and whether anyone actually calculated the size.
This page breaks down what drives the price, what a complete quote should include, and what higher efficiency actually saves. The price ranges are typical figures from contractor pricing, not quotes; your local market and your house decide the real number.
Replacing a central air conditioner on existing ductwork typically costs about $3,100 to $7,200 installed for a 3-ton, 14-SEER (about 13.3 SEER2) system, or about $4,150 to $9,700 at 16 SEER (about 15.2 SEER2); that is about $5,150 and $6,900 at the mid estimate. Replacing the AC and furnace together, or a first-time system that needs new ductwork, costs more and depends on the extra work. Size, efficiency, duct and electrical work, and local labor rates move the number, so get at least three itemized quotes.
| Job | Typical installed cost | Usually includes |
|---|---|---|
| AC replacement, existing ducts (3 tons) | about $3,100 to $7,200 at 14 SEER, about $4,150 to $9,700 at 16 SEER | Outdoor unit, matched indoor coil, line set, labor, thermostat |
| AC and furnace replacement | Costs more (two separate equipment swaps) | Complete heating and cooling system |
| First-time central air with new ducts | Costs more (new ductwork on top) | System plus full duct installation |
| Heat pump instead of AC | See the heat pump cost guide | Heat pump, matched coil or air handler, labor, thermostat |
REMDB prices the air-conditioner equipment swap on existing ducts, not the combinations. Replacing the AC and furnace together is really two separate equipment swaps, a first-time system adds new ductwork on top, and a heat pump is priced on the heat pump installation cost page. Those jobs cost more and vary with the extra work.
The installed-cost figures come from NREL's National Residential Efficiency Measures Database (REMDB), 2024 release, which models a retrofit replacement in 2023 dollars and gives a low, mid and high estimate. They are total installed costs, including removing the old equipment and before any rebates, so prices have generally risen since 2023. Work REMDB does not price, such as ductwork, panel service upgrades and AC-plus-furnace combinations, has no figure here and is described as a cost driver instead.
What a complete quote includes
An itemized quote should list each of these, so you can compare contractors line by line:
- Outdoor condenser, with its model number.
- Indoor evaporator coil, matched to the condenser. The pair should appear together in the AHRI directory, which is what makes the rated efficiency real.
- Refrigerant line set, new or reused, and whether the old one gets flushed and pressure-tested.
- Electrical work: disconnect, whip and breaker, and any upgrade the panel needs.
- Thermostat.
- Permits and inspection, which most jurisdictions require.
- Labor, including removing the old unit, recovering its refrigerant, brazing, evacuating the lines, charging, and start-up checks.
Refrigerant recovery and charging legally require an EPA Section 608-certified technician, which is one reason central air isn't a DIY job.
Cost by system size
Bigger systems cost more to buy and install. REMDB prices central air conditioners in whole-ton steps from 2 to 5 tons; typical installed ranges for a straight replacement, low to high:
| Size | 14 SEER (about 13.3 SEER2) | 16 SEER (about 15.2 SEER2) |
|---|---|---|
| 2 tons | about $2,800 to $6,500 | about $3,850 to $9,000 |
| 3 tons | about $3,100 to $7,200 | about $4,150 to $9,700 |
| 4 tons | about $3,400 to $7,900 | about $4,450 to $10,350 |
| 5 tons | about $3,650 to $8,550 | about $4,750 to $11,050 |
The right size comes from your house, not your old unit's label. An oversized system costs more up front and runs worse, cycling on and off before it dehumidifies. Check a quote's tonnage against our AC tonnage calculator, and ask for the contractor's Manual J load calculation.
What higher efficiency actually saves
Annual cooling cost for a 3-ton system at $0.18 per kWh, in a mid-range summer (1,500 full-load hours) and a hot one (2,500 hours):
| SEER2 | 1,500 hours | 2,500 hours |
|---|---|---|
| 13.4 | $725 | $1,209 |
| 14.3 | $680 | $1,133 |
| 15.2 | $639 | $1,066 |
| 16 | $608 | $1,013 |
| 17 | $572 | $953 |
| 20 | $486 | $810 |
| 24 | $405 | $675 |
Cost = 36,000 BTU/hr × hours ÷ (SEER2 × 1,000) × $0.18. Going from 14.3 to 16 SEER2 saves about $72 a year at 1,500 hours and $120 at 2,500.
At the mid estimate, a 3-ton system costs about $1,750 more at 16 SEER than at 14 SEER, about $6,900 against $5,150. Using the 13.4 and 15.2 SEER2 rows above, that step saves about $86 a year at 1,500 cooling hours and about $143 at 2,500, so the premium pays back in about 12 to 20 years, sooner where summers are long or electricity is expensive. The SEER2 comparison calculator runs the numbers with your own hours and rate.
The federal minimum for split central ACs is 13.4 SEER2 in the North. In the South and Southwest it's 14.3 below 45,000 BTU/hr (under about 3.75 tons) and 13.8 at 45,000 and above. See minimum SEER2 by state.
What adds to the cost
- Ductwork. Modifying or replacing ducts adds the most, and more for multi-story homes; REMDB prices the equipment swap, not duct work, so this is a separate cost driver. Leaky ducts are worth sealing while the system is being replaced.
- Electrical panel upgrade. An older 100-amp panel may need upgrading to carry the new circuit; a 200-amp panel replacement runs about $1,000 to $3,100 (NREL REMDB, rough). See our panel upgrade cost guide.
- A new line set. Newer systems use lower-GWP refrigerants, and the installer decides whether the old copper lines can be reused or need replacing.
- Difficult access, such as rooftop units, tight attics or long line runs.
- Asbestos, common in duct insulation in older homes, which must be removed by a licensed abatement contractor.
- Extras like zoning, a whole-house dehumidifier or UV lights, which are optional.
Tax credits and rebates in 2026
- The federal 25C credit expired for equipment placed in service after December 31, 2025, under the One Big Beautiful Bill Act. Through 2025 it covered up to $600 for a qualifying central air conditioner. It does not apply to 2026 installs.
- HEAR rebates don't cover central air conditioners. The income-qualified High-Efficiency Electric Home Rebate program covers heat pumps and some other electric upgrades. If you're choosing between a central AC and a heat pump, that can change the math; see heat pump installation cost.
- HOMES rebates are based on whole-home energy savings and run by each state, so availability varies.
- Utility rebates vary widely. The DSIRE database lists programs by state and utility.
Installation day
A straight replacement is usually finished in a day. The crew removes the old condenser and coil and recovers the refrigerant, sets the new outdoor unit and coil, connects the refrigerant lines and wiring, then pulls a vacuum on the lines before charging the system. A good installer finishes with start-up checks and gives you the readings.
Questions to ask before you sign
- Will you perform a Manual J load calculation?
- What are the model numbers of the condenser, coil and furnace or air handler, and are they an AHRI-matched system?
- Are you reusing the line set? If so, how will you flush and test it?
- Are permits and inspection included?
- What's the warranty on the equipment, and separately on your labor?
- Who registers the equipment warranty?
- Will you give me the start-up readings (superheat, subcooling, airflow)?
Paying for it
Most contractors offer financing: 0% promotional plans, dealer loans, home equity loans or lines of credit, personal loans, and in some states PACE programs repaid through property taxes. Read promotional terms carefully. Some "0% for 18 months" offers are deferred interest: miss the payoff date and all the interest from day one comes due.
Frequently asked questions
Can I install central air myself?
No. Handling refrigerant requires EPA Section 608 certification, the electrical work usually needs a permit, and a DIY install can void the equipment warranty. You can save on the scope, not the installer.
Should I replace my AC and furnace at the same time?
Often, if the furnace is near the end of its life. Replacing both in one job avoids paying for two installs, and a matched indoor and outdoor combination is what delivers the rated efficiency. If the furnace is young and working, replacing only the AC and a matched coil is common.
Why do central AC quotes vary so much?
Different equipment tiers, different scope (ducts, electrical, line set), different overhead, and whether the contractor sized the system properly. Compare itemized quotes for the same size and efficiency.
Is a higher-SEER2 air conditioner worth it?
It depends on your cooling hours and electricity rate. Stepping a 3-ton system from 14 to 16 SEER (about 13.4 to 15.2 SEER2) costs about $1,750 more installed at the mid estimate and saves about $86 to $143 a year, so it pays back in about 12 to 20 years.
Is there a tax credit for central air in 2026?
Not at the federal level. The 25C credit expired for equipment placed in service after December 31, 2025, and HEAR rebates cover heat pumps, not central air conditioners. Check DSIRE for state and utility rebates.
Sources & References
- IRS: Energy Efficient Home Improvement Credit (25C)
- EPA: Section 608 refrigerant management
- DSIRE: Database of State Incentives for Renewables & Efficiency
- AHRI: Directory of Certified Product Performance
- ACCA: Manual J, Residential Load Calculation
- NREL: National Residential Efficiency Measures Database (REMDB), 2024