How Much Does AC Replacement Cost?

Replacing a central air conditioner typically costs $11,500–$16,000 installed for a 3-ton system in an average home (about 1,500–1,800 sq ft), at 2026 national-average prices. Smaller homes with a 2-ton unit usually run $7,900–$11,000, while a large home needing 5 tons of cooling can reach $19,000–$25,500. Every range here is a national average that includes the equipment, labor, permits, disposal, sales tax, and a 10% contingency.

This guide covers what an AC replacement includes, how efficiency levels change the price, what drives the cost up or down, the extras quotes most often skip, permits, and how long the job takes. It's written for homeowners whose cooling system is aging, failing, or so inefficient that a repair estimate no longer makes sense. To price your own home's system by tonnage, efficiency level, and city, use the HVAC cost calculator.

Cost at a glance

The right size for your home is measured in tons of cooling capacity, not square feet alone — a ton moves about 12,000 BTU per hour. A proper load calculation (Manual J) decides the size, and bigger is not better: an oversized unit cools too fast to dehumidify, short-cycles, and wears out sooner.

Ranges are national averages from our calculator, including tear-out of the old equipment, a new line set, electrical disconnect, pad, thermostat, permits, and a 10% contingency. Labor rates in your metro can move them 10–40% either way; see how we calculate costs.

Efficiency matters almost as much as size. A matched outdoor condenser and indoor coil set costs roughly:

SEER2 (Seasonal Energy Efficiency Ratio 2) is the standard cooling-efficiency rating. The federal minimum is 14 SEER2 in most of the country, so every new system at least meets it. Two-stage and variable-speed units run at lower output on mild days, which means steadier temperatures, much better humidity control, and quieter operation — in hot-humid climates like the Gulf Coast, that comfort difference matters more than the energy savings.

What's included in the price

A complete AC replacement quote should cover all of the following, not just the metal box outside:

• Outdoor condenser and indoor coil/air handler. The two halves of the system must be a matched, AHRI-certified set. The equipment is usually the biggest single share of the bill, roughly half of the total on a standard-efficiency job.
• Refrigerant line set and flush. New copper lines between the indoor and outdoor units, pressure-tested and evacuated. Reusing an old line set to save a few hundred dollars is a common source of leaks and warranty denials.
• New electrical disconnect and whip. A code-compliant disconnect box by the condenser with a short flexible conduit run. If your existing wiring is undersized for the new unit, the electrician may need to pull a larger circuit — ask whether that's included.
• Composite pad and float safety switch. A level pad for the condenser and a switch that shuts the system down if the condensate drain backs up, so a clogged drain doesn't flood a ceiling.
• Smart thermostat and commissioning. A new thermostat plus proper startup: charging the refrigerant to spec, verifying airflow, and testing the full system. Commissioning is where good installs separate from bad ones.
• Mechanical permit and HERS rating. The mechanical permit and, in many jurisdictions, a home energy rating verification that the installed system matches what was permitted.

Also folded into the ranges above: haul-away of the old condenser and coil, sales tax on the equipment, and a 10% contingency for small surprises found on the day of the install.

What drives the cost up or down

• Tonnage. Each additional ton adds roughly $3,800–$5,300 at high-efficiency pricing. Sizing comes from a Manual J load calculation that accounts for insulation, window area, ceiling height, and climate — not just square footage. If a contractor sizes by "what was there before" or a rule of thumb, get a second opinion.
• Efficiency level. Stepping a 3-ton system from standard 14 SEER2 to a two-stage 16–17 SEER2 unit adds roughly $2,300–$3,500; going to a variable-speed inverter system adds roughly $7,800–$10,500 over the standard price. The payback is slow in mild climates and fastest where the AC runs six months a year.
• Furnace or air handler condition. If your gas furnace is healthy and only the cooling half is failing, you replace the condenser and indoor coil only, which lands in the ranges above. Replacing the furnace at the same time — worth considering when it's 15 years or older — pushes the project toward the top of each range and is priced more fully in how much a furnace replacement costs. See also what a full new HVAC system costs if you're weighing both halves together.
• Ductwork condition. Leaky or undersized ducts can make a new high-efficiency unit perform like a much cheaper one. Sealing and repairs typically run $800–$2,200, and adding or enlarging a return air run costs a few hundred more. Duct replacement, if the whole system is undersized or damaged, is a separate project entirely.
• Refrigerant type. New systems use R-410A or the newer low-global-warming-potential refrigerants R-32 and R-454B. Equipment designed for the newer refrigerants is slightly more expensive but keeps you ahead of the phase-down schedule for older refrigerants.
• Location and timing. Labor rates move the ranges 10–40% by metro. In New York City the average 3-ton job runs $15,500–$21,000 versus $11,500–$16,000 nationally; in Austin it's about $12,500–$17,000. Summer emergency replacements also cost more, because you're buying speed. If the system still cools, scheduling the replacement for spring or fall can cut the price.

What quotes often leave out

Compare quotes line by line — the cheapest bid usually wins by leaving scope out, not by being more efficient. Check for:

• A Manual J load calculation. If the quote doesn't mention one, the size is a guess. Oversizing is the most expensive mistake in this business, and it can't be fixed after the install.
• AHRI certified reference number. This proves the indoor and outdoor units are a rated, matched set. Without it, the efficiency rating on the brochure is meaningless and the manufacturer can deny warranty claims.
• SEER2, EER2, and HSPF2 ratings in writing. The quote should document the efficiency ratings you're paying for, not just a brand name and tonnage.
• 10-year parts and labor warranty terms. Parts warranties are standard; labor warranties of 10 years are not. Ask who honors the labor warranty and what voids it — skipped annual maintenance voids some of them.
• Ductwork evaluation. Most quotes assume your existing ducts are fine. Ask for a written statement on their condition, or a separate price for sealing, so the cost doesn't appear mid-install.
• Attic access and structural work. If the new air handler is larger than the old one, widening the attic opening or adding a service platform can add $350–$750.
• Thermostat and condensate plumbing. Confirm whether a new thermostat and condensate drain work are included — both are routine upsells presented as add-ons on the day of install.

Before you sign, paste the quote into the Quote Checker to see what's missing.

How to save without cutting corners

This is not a DIY project: handling refrigerant legally requires EPA certification, and the electrical and brazing work has to be right for the warranty to hold. But there are honest ways to pay less:

• Keep a healthy furnace. If the furnace has years of life left, replace only the cooling half. A matched condenser and coil on an existing furnace is the most common residential job.
• Buy the efficiency sweet spot. The standard 14 SEER2 unit is the cheapest legal option, but the two-stage 16–17 SEER2 tier usually delivers the best balance of upfront cost, comfort, and energy use in hot climates. The ultra-inverter tier is worth it mainly for large, hot-climate homes or households that value humidity control highly.
• Replace before it dies. A dead compressor in August means you're buying speed, not value. If your unit is 12–15 years old and needing a repair over $1,000, price a replacement in the off-season instead.
• Get three quotes with identical scope. Same tonnage, same efficiency tier, same line items. The spread between a disciplined shop and a sloppy one is routinely 15–25% — but only compare quotes that include a Manual J, a matched AHRI set, and the line items above.
• Check utility rebates. Rebates for high-efficiency AC vary by utility and change often, so confirm the current offers with your utility before you buy. Federal energy tax credits for equipment installed after December 31, 2025 have expired; check energystar.gov and your utility for what remains.

Permits and timeline

A mechanical permit is usually required to replace a central AC, and the work must meet current code — including the disconnect, pad, and condensate safety switch — before the inspector signs off. Your contractor should pull the permit and schedule the inspection; a quote that asks you to handle the permit is a red flag.

A straightforward replacement takes one to two days: a crew of two to three, tear-out in the morning, set and braze the new equipment, charge and commission it, and a final walkthrough. Add a day if ductwork repairs, electrical upgrades, or attic access work are involved. From first quote to cold air, expect one to three weeks in the shoulder seasons and potentially longer in a summer heat wave, when every contractor's schedule is full.

If your current system is limping along with a repair quote in hand, that repair cost is worth weighing against a replacement: once a single repair crosses roughly a third of the replacement price on a unit past 12 years old, replacement is usually the better money.