Central AC cost by size
Size, measured in tons of cooling, sets the base price. Each step up in size adds roughly $1,000 or more, so a correctly sized system matters twice: an oversized unit costs more to buy and cools poorly, short-cycling without removing humidity.
| AC size | Installed price |
|---|---|
| 2 ton (800–1,200 ft²) | $3,200–$6,500 |
| 3 ton (1,500–1,800 ft²) | $4,500–$8,500 |
| 4 ton (2,000–2,400 ft²) | $5,200–$9,800 |
| 5 ton (2,500–3,000 ft²) | $5,800–$11,000 |
2- and 3-ton prices are directly sourced. 4- and 5-ton prices are derived from published size step-ups rather than quoted directly, so treat them as a wider estimate.
How much efficiency is worth paying for
Efficiency is rated in SEER2. The federal minimum is 14.3 SEER2 in the South and Southwest and 13.4 SEER2 in the North. Moving up to 16–17 SEER2 typically adds $800–$2,800; variable-speed systems at 18–20+ SEER2 can cost close to twice as much as a baseline system.
Whether the premium pays back depends on how long your AC runs. In long cooling seasons like Phoenix or Houston, a high-efficiency unit can recoup its premium in several years; where summer is short, the payback can stretch past a decade, and a mid-tier unit is usually the better buy.
Extra costs to expect
| Item | Typical cost | When it's needed |
|---|---|---|
| New line set, disconnect or pad | $400–$1,800 | Older homes, or when the new refrigerant needs new lines |
| Duct repair or sealing | $500–$5,000 | Leaky, undersized or damaged ductwork |
| Permit | $100–$500 | Required in most municipalities |
The refrigerant change
New central AC systems are moving from R-410A to R-454B refrigerant. Installers need different tools and leak-detection equipment, which is part of why 2026 quotes look different from a few years ago. Expect the outdoor condenser and indoor coil to be replaced together rather than pairing a new unit with old components.
Is there a federal tax credit for a new AC in 2026?
No. The federal Energy Efficient Home Improvement Credit (Section 25C) does not apply to equipment placed in service after December 31, 2025, although some cost guides still mention it. Check your utility and state for current rebates.
Repair or replace?
If your system is 12–15 years old or more and needs a major repair such as a compressor or evaporator coil, replacement usually makes more sense. For smaller problems, see our AC repair cost guide first.
Questions to ask before you hire
- Did you do a Manual J load calculation to size the system?
- Is this a condenser-and-coil replacement, and which refrigerant does it use?
- Are the line set, electrical disconnect, pad and permit included?
- Will you register the equipment warranty for me? Unregistered systems can lose years of parts coverage.
- What's the labor warranty, separate from the manufacturer's?
Methodology and sources
We start from an installed price by system size, apply an efficiency multiplier, and adjust the labor share for your state's HVAC technician wages. Add-ons and permits are priced separately. Read how we estimate costs.
- HVAC Project Cost: 2-ton AC replacement and AC replacement cost
- PickComfort: AC unit replacement cost — size and efficiency step-ups
- Team Enoch: central AC replacement cost — 3-ton pricing
- HowManyBTUs: AC replacement calculator — high-efficiency premium
- Atlas AC Repair: HVAC replacement cost — 14 vs 20 SEER2 comparison
- Pipelineon: AC replacement cost — refrigerant change, older-home add-ons
- NearbyHunt: AC replacement cost — SEER2 minimums, warranty registration
- HVAC Project Cost: repair vs replace and AC Direct: 12 years old, repair or replace? — age and repair-or-replace guidance
- BLS OEWS May 2025, State (SOC 49-9021, HVAC mechanics) — state labor index
What each source reports
Our estimate does not rely on any single page. This table lists each page we used and the figures it reports, so you can see where the ranges come from.
| Source | What it reports |
|---|---|
| HVAC Project Cost |
|
| Team Enoch (Texas contractor) | most homeowners pay $6,500-$8,500 for a mid-efficiency 3-ton system |
| PickComfort |
|
| HVAC Project Cost |
|
| howmanybtus.com |
|
| Atlas AC Repair | a 3-ton 14 SEER2 system installed at $9,983 vs a 20 SEER2 unit at $19,838, almost twice as much |
| Pipelineon | permit, electrical disconnect, refrigerant line work and pad or stand replacement add $400-$1,800 in older homes |
Common questions about AC unit costs
How much does AC unit cost?
A typical job (3 ton, standard efficiency) comes to about $6,550 nationally, within a range of $4,600 to $9,000. Use the calculator above to adjust for your state, the options you choose and any extras.
How much does a 3-ton or 4-ton AC unit cost?
At standard efficiency, installed prices are about $3,300–$7,000 for 2 tons, $4,600–$9,000 for 3 tons, $5,300–$10,300 for 4 tons and $5,900–$11,500 for 5 tons. Size is set by your home’s cooling load, not by the price.
How much does it cost to install central air?
The sizes above are priced as a replacement system. Duct repair or sealing is a separate line, about $500–$5,000, and a new line set, disconnect or pad is priced separately in the table of extra costs above.
How much does it cost to replace both the AC and the furnace?
They are separate jobs on this site. A 3-ton AC unit comes to about $4,600–$9,000 here, and a gas furnace to about $5,280–$9,300 on the furnace replacement cost page. Ask for a combined quote and compare it with these figures.
Where do these prices come from?
They come from 7 published cost pages from 6 publishers, last checked Sep 24, 2026. We report what those pages say and do not invent figures; the table above shows each source.
How does my state change the estimate?
The labor part of the price is scaled by the average wage for the relevant trade in your state, using Bureau of Labor Statistics data. Materials and equipment are not adjusted.
Why might a contractor's quote differ from this estimate?
A quote reflects your specific scope, access, local demand and what the contractor includes. Ask for line items rather than a single total so you can compare bids on the same basis.
All 7 sources behind these prices
Every figure in the calculator comes from one or more of these pages, with the number each one supports in the link text.
- HVAC Project Cost: a 2-ton central AC split system costs $3,200-$6,500 installed in 2026; most comparable mid-efficiency replacements land at $3,800-$5,200
- Team Enoch (Texas contractor): most homeowners pay $6,500-$8,500 for a mid-efficiency 3-ton system
- PickComfort: add about $1,000 when upgrading from 2 to 3 tons
- HVAC Project Cost: equipment costs jump $2,000-$4,000 between a 1.5-ton unit and a 5-ton system
- Baseline tier the size prices above describe (standard condenser + coil)
- Atlas AC Repair: a 3-ton 14 SEER2 system installed at $9,983 vs a 20 SEER2 unit at $19,838, almost twice as much
- Pipelineon: permit, electrical disconnect, refrigerant line work and pad or stand replacement add $400-$1,800 in older homes