The quick answer#
A standard efficiency central air replacement costs $5,000 to $8,300 installed in 2026, and a mid-range system $8,300 to $12,500. That assumes the existing ducts stay. With new ductwork the job runs $9,000 to $16,000.
Standard system
$5,000–$8,300installedMid-range system
$8,300–$12,500installedWith new ductwork
$9,000–$16,000installed3 ton system
$5,800–$7,800basic installationThese are HomeGuide's ranges. Before you compare quotes, know the size of system your house needs, because the tonnage moves the price and an oversized unit costs more and cools worse. The HVAC calculator gives a rule-of-thumb tonnage from your square footage and climate, and our AC size chart lays the same figures out by house size.
Before you price anything
What size AC does your house need?
Enter the area, ceiling height, climate and sun exposure for a cooling load in BTU and tons, the number every quote is built on.
Cost by tier#
HomeGuide groups central air into three tiers, and the difference between them is mostly the compressor: single-stage units run flat out whenever they are on, two-stage units have a lower setting, and variable speed units adjust continuously.
| Tier | Installed | What you get |
|---|---|---|
| Entry-level | $5,000–$8,300 | Single-stage cooling, standard efficiency |
| Mid-range | $8,300–$12,500 | Two-stage cooling, better efficiency |
| High-end | $12,500–$14,000 or more | Variable speed, maximum efficiency |
HomeGuide's figures, on existing ductwork. Variable speed systems cost the most and handle humidity best.
Cost per ton#
A ton of cooling is 12,000 BTU. Bigger systems cost more, but not in proportion: going from 2 tons to 4 adds about $1,500 to $2,000 on HomeGuide's figures, less than the step from one tier to the next.
| Size | BTU | Unit only | Installed |
|---|---|---|---|
| 1.5 tons | 18,000 | $2,200–$3,500 | $4,700–$6,500 |
| 2 tons | 24,000 | $2,500–$3,800 | $5,000–$6,800 |
| 2.5 tons | 30,000 | $2,900–$4,200 | $5,400–$7,200 |
| 3 tons | 36,000 | $3,300–$4,800 | $5,800–$7,800 |
| 3.5 tons | 42,000 | $3,700–$5,300 | $6,200–$8,300 |
| 4 tons | 48,000 | $4,000–$5,800 | $6,500–$8,800 |
| 5 tons | 60,000 | $4,500–$6,500 | $7,000–$9,500 or more |
HomeGuide's figures for a basic installation, not including any ductwork changes. To read your size off a chart, our AC size chart gives tonnage for eight house sizes across four climates, and the HVAC calculator adjusts it for ceiling height, sun and occupancy. Either one is a rule of thumb; a Manual J load calculation is the real method.
Cost by efficiency#
Efficiency is rated in SEER2 on central air conditioners made since 2023. The federal minimum is 13.4 SEER2 in the north and 14.3 in the Southeast and Southwest, so in the Southeast and Southwest the first row below, and the low end of the second, fall short of it.
| SEER2 rating | Unit only | Installed |
|---|---|---|
| Up to 13.4, standard | $2,800–$4,900 | $5,300–$7,900 |
| 14.0 to 14.7, high | $4,200–$6,300 | $6,700–$9,300 |
| 15.0 to 17.2, high | $5,000–$7,600 | $7,500–$10,600 |
| 16.5 to 18.5, very high | $6,600–$9,200 | $9,100–$12,200 |
| Up to 25.8, maximum | $8,900–$14,300 | $11,400–$17,300 or more |
HomeGuide's figures for a basic installation. Its rows overlap because it maps each old SEER band to a SEER2 range.
HomeGuide notes that southern regions often need a higher efficiency unit because the warm season runs longer. A tighter house helps more than either: insulation and air sealing cut the load the system has to meet, which can drop it a size. The insulation calculator gives the R-value your attic should have, and our insulation cost guide prices getting there.
Ductwork and permits#
Most replacements reuse the existing ducts, and that is what keeps them in the $5,000 to $12,500 range. When the ducts are leaking or the wrong size, the price climbs.
| Item | Cost |
|---|---|
| Minor duct sealing and repairs | $300–$1,500 |
| Replacing failed ductwork | $1,400–$5,600 or more |
| Central AC with new ductwork, installed | $9,000–$16,000 |
| Permit, replacement | $100–$250 |
| Permit, new install with ductwork | $250–$1,500 |
HomeGuide's figures. Sealing and insulating ducts that run through an unconditioned attic is usually the best money you can spend on an existing system.
If the house has no ducts at all, compare central air against a ductless system before you get quotes. Our mini-split vs. central AC guide prices both, and with no ducts the two land in overlapping ranges.
Replacing more than the AC#
If the furnace is as old as the air conditioner, many contractors quote both together, and a heat pump does both jobs with one outdoor unit.
| System | Unit only | Installed |
|---|---|---|
| Furnace and AC | $6,500–$11,000 | $10,500–$18,500 |
| Air-source heat pump | $4,000–$9,000 | $8,000–$15,000 |
HomeGuide's figures. A new system lasts 15 to 20 years on average, and a repair runs $150 to $650, so on a unit near the end of that span a large repair is often the moment to replace it.
Checking a quote#
Start with the tonnage. Run your house through the HVAC calculator, then ask the contractor how they sized the system. A quote that only matches the old unit's size, with no load calculation, may be carrying an old mistake forward, and an oversized system short cycles and leaves the house clammy.
Then find the quote's tier and tonnage in the tables above and see where it lands. Ask four things: whether the indoor coil is replaced along with the outdoor unit, whether the permit is included, whether any duct sealing or repair is included, and what SEER2 rating the matched system carries. Off-season timing helps too: late fall and early spring are when contractors discount, and May through August is when they are busiest.
If the house runs hot even with a working system, check the attic before the AC. The insulation calculator shows how far short of the recommended R-value it is.
Save the AC cost chart#
Installed cost for central air from 1.5 to 5 tons. Save it before you start collecting HVAC quotes.
Save to PinterestOpens Pinterest with the chart and link ready to go.
Common questions#
How much does it cost to replace a central AC unit?#
$5,000 to $8,300 installed for a standard efficiency system and $8,300 to $12,500 for a mid-range one, on existing ductwork. High-end variable speed systems run $12,500 to $14,000 or more. With new ductwork the job is $9,000 to $16,000.
How much does a 3 ton AC unit cost?#
$3,300 to $4,800 for the unit and $5,800 to $7,800 installed for a basic installation, on HomeGuide's figures. A 2 ton system is $5,000 to $6,800 installed and a 4 ton system $6,500 to $8,800.
Does AC replacement include ductwork?#
Usually not. Most replacements reuse the existing ducts. Minor duct sealing and repairs add $300 to $1,500, replacing failed ductwork $1,400 to $5,600 or more, and a central system with new ductwork runs $9,000 to $16,000 installed.
How long does a central air conditioner last?#
15 to 20 years on average. A repair runs $150 to $650, so on a unit near the end of that span a large repair is often the point where replacing it makes more sense.