Most published cost guides put a central AC replacement with usable existing ductwork somewhere around $4,000 to $8,000 installed, and the national averages they report sit close to $6,000. A small, minimum-efficiency swap can come in under that range, while a large variable-speed system or a job that needs new ducts or electrical work can run past $12,000. The size of the system, its efficiency tier and how much of the existing setup has to change move the price more than the brand name does.
This page is about replacing an existing central air conditioner. If your home has never had central air, the central AC installation cost for first-time installs is the better guide, and our HVAC replacement cost for every system type covers furnace, heat pump and combined jobs.
What an AC Replacement Usually Includes
"AC replacement" can mean three different jobs, and the scope explains most of the gap between quotes for the same house.
| Scope | What gets replaced | When it fits | Relative cost |
|---|---|---|---|
| Outdoor unit only | Condenser | Rarely recommended now; only when a compatible, matched coil is already in place | Lowest, but often not allowed by the new unit's rating or warranty |
| Outdoor unit and indoor coil | Condenser, evaporator coil, usually the line set flush or replacement | The standard central AC replacement when the furnace stays | Typical range on this page |
| Full split system | Condenser, coil and furnace or air handler | Furnace or air handler is near the end of its life or can't move enough air | Higher, but labor is shared across both jobs |
| AC to heat pump | Heat pump outdoor unit, matched coil or air handler | You want efficient electric heat too, often keeping the furnace as backup | Higher than an AC alone; see the heat pump installation cost guide |
The middle row is what most people mean by central air replacement. The outdoor unit and indoor coil work as a pair: the efficiency rating on the box belongs to a specific combination of outdoor unit and coil, listed in the AHRI directory, and the manufacturer's warranty often assumes that pairing.
Typical AC Replacement Cost Ranges
Cost guides agree on the broad picture even though their exact figures differ:
- Straight replacement with good ducts: roughly $4,000 to $8,000 for the outdoor unit, matched coil and installation, with reported averages near $6,000.
- High-efficiency or variable-speed systems: the upper tiers commonly land from the high end of that range up to $12,000 or more.
- Added ductwork: new or replacement duct runs commonly add a few thousand dollars, and a full duct rebuild can rival the cost of the equipment.
Treat these as typical ranges, not prices. Your number depends on local labor rates, the season and what the contractor finds when they look at your system.
Cost factors that move the price
| Factor | Pushes cost up | Keeps cost down |
|---|---|---|
| Size (tonnage) | Larger homes needing 4 to 5 tons | Smaller homes needing 1.5 to 2.5 tons |
| Efficiency (SEER2) | Two-stage or variable-speed, high SEER2 | Single-stage near the federal minimum |
| Refrigerant change | New line set or coil needed for R-454B or R-32 | Line set can be flushed, pressure tested and reused |
| Ductwork | Undersized, leaky or damaged ducts | Ducts sized right and in good shape |
| Electrical | Panel upgrade, new disconnect or circuit | Existing circuit matches the new unit's requirements |
| Access | Rooftop, attic coil, tight crawlspace | Ground-level pad and basement furnace |
| Timing | Peak summer, emergency replacement | Spring or fall, planned ahead |
| Extras | Thermostat, condensate pump, pad, crane | Reusing the pad, thermostat and drain |
Size is set by your home, not by preference. A contractor should run a Manual J load calculation instead of copying the old unit's tonnage, since many older systems were oversized. Our guide on how to size a new AC explains how that works.
Efficiency is the factor you control most. A higher SEER2 rating costs more up front and less every month, so payback depends on your climate and how long you'll stay. The guide to what SEER and SEER2 ratings mean shows how to estimate the savings between two ratings.
The Refrigerant Switch and Why It Matters for Your Quote
Since January 1, 2025, new residential air conditioner and heat pump systems made or imported in the U.S. must use a refrigerant with a global warming potential (GWP) of 700 or lower under EPA's AIM Act rules. In practice that means R-454B or R-32 instead of R-410A; our R-32 vs R-454B guide compares the two. Many sources still repeat an older January 1, 2026 installation deadline, but a May 2026 EPA reconsideration rule removed the installation deadline for systems whose components were all made or imported before 2025. Leftover R-410A stock can still be installed, and existing R-410A systems can still be repaired. Some states set their own rules, so ask your contractor what applies where you live.
What this means for you:
- The coil has to match the refrigerant. A new R-454B or R-32 outdoor unit needs an indoor coil designed and rated for that refrigerant. Your old R-410A or R-22 coil generally can't stay.
- The line set may need attention. Contractors often flush and reuse a line set in good condition when its size suits the new unit. Damaged, undersized or buried lines get replaced.
- New safety parts. R-454B and R-32 are mildly flammable (A2L) refrigerants, and many indoor units built for them include a refrigerant leak sensor.
- Leftover R-410A stock. If you're offered an R-410A system, ask how it will be serviced over its life, since R-410A supply is being phased down. Our R-410A refrigerant guide covers what that means for owners.
If your current system still uses R-22 refrigerant, it hasn't been produced or imported since January 1, 2020, so any major leak repair gets expensive fast.
Repair or Replace Your AC?
Two rules of thumb get quoted often. Neither is a law, but both are useful starting points.
- The 50% rule: if a repair costs about half of what a new system would, replacing usually makes more sense.
- The $5,000 rule: multiply the unit's age by the repair cost. If the result is above $5,000, lean toward replacement. A 12-year-old unit with a $500 repair scores 6,000.
Replacement usually wins when several of these apply:
- The system is past 10 to 15 years old
- It uses R-22 and has a refrigerant leak
- The compressor or outdoor coil has failed outside warranty
- Repairs have become a yearly event
- Some rooms never cool well, or humidity stays high
- Energy bills keep climbing with no other explanation
A failed capacitor, contactor or fan motor on a younger unit is a repair, not a replacement. Our guide to AC repair cost by part shows where common repairs fall, and how long an AC unit lasts covers the age question in more depth.
How to Read an AC Replacement Quote
Most guides tell you to get three quotes. Fewer explain how to compare them. Ask each contractor to list these items, then compare them line by line.
- Model numbers for the outdoor unit, the indoor coil and any furnace or air handler, plus the AHRI certificate number for that exact combination.
- Tonnage and how it was chosen. "Same as the old one" is a weaker answer than a Manual J calculation.
- Refrigerant type and what happens to the line set: reuse after flushing and pressure testing, or replacement.
- Pad, disconnect, electrical whip and breaker. These small items are where change orders come from.
- Condensate drain, float switch and pump if the coil sits in an attic or basement.
- Permit and inspection. Most jurisdictions require a mechanical permit for AC replacement.
- Commissioning. How the installer will verify charge and airflow at startup, such as superheat or subcooling readings and a static pressure test.
- Warranty. Parts term, labor term, who registers the equipment and the registration deadline. Some manufacturers shorten parts coverage if the unit isn't registered in time.
- Removal and disposal of the old unit, including refrigerant recovery.
A quote that lists only "3-ton AC system, installed" makes comparison impossible. If two bids differ by thousands, the difference is almost always in scope, efficiency tier or warranty, and the itemized list shows which.
Red flags
- Tonnage picked without measuring the house or asking about insulation and windows
- An outdoor unit quoted without a matching coil
- Pressure to sign the same day for a "today only" price
- No permit, or a suggestion that you pull it yourself
Ways to Lower Your AC Replacement Cost
- Replace on your schedule. A failing unit replaced in spring or fall gives you time to compare bids. An emergency swap in a heat wave doesn't.
- Right-size the system. A correct load calculation can land on a smaller, cheaper unit than the one you have now.
- Pick the efficiency tier that pays back for you. In a hot climate with long cooling seasons, a higher tier earns its premium faster than in a mild one.
- Bundle when it makes sense. If the furnace is also near the end, replacing both together shares labor, permits and startup.
- Check incentives. Federal tax credit rules changed in 2025, so check current federal, state and utility rebates before you count on one.
- Keep it maintained. Annual service protects the new system and helps when you file a warranty claim.
Note that ENERGY STAR stopped certifying central air conditioners in 2026 and now certifies heat pumps instead, so don't expect to see the label on a new central AC.
Frequently Asked Questions
How much does it cost to replace a central air conditioner?
Most published cost guides put a central AC replacement with existing, usable ductwork somewhere around $4,000 to $8,000 installed, with reported national averages close to $6,000. Higher-efficiency variable-speed systems, new ductwork, electrical upgrades or a hard install can push the total past $12,000.
Can I replace just the outdoor AC unit?
Sometimes, but it's usually a poor bet. A new condenser needs an indoor coil rated for the same refrigerant and matched to it for its efficiency rating and warranty. Since new equipment now uses lower-GWP refrigerants such as R-454B or R-32, an older R-410A or R-22 coil generally isn't compatible, so most replacements include the coil.
Should I replace my furnace when I replace my AC?
If the furnace is within a few years of the end of its life, replacing both at once often saves on labor and lets the installer match the blower to the new coil. If the furnace is fairly new and has a blower that can deliver the airflow the new AC needs, replacing only the cooling side is reasonable.
How long does AC replacement take?
A like-for-like replacement of the outdoor unit and indoor coil usually takes one day. New ductwork, a new line set through finished walls, an electrical panel upgrade or a switch to a heat pump can add a day or more.
Is it worth replacing a 15-year-old AC?
Often, yes, if it needs a major repair. Central air conditioners commonly last about 15 years, and ENERGY STAR suggests considering replacement once a unit is more than 10 years old. A 15-year-old unit facing a compressor, coil or large refrigerant leak repair is usually a better candidate for replacement than repair.