How much does it cost to replace a central air conditioner?
Replacing a central air conditioner costs $5,800 to $7,800 installed for a common 3 ton system, on HomeGuide's published tonnage table, ductwork excluded.
Tonnage is the axis that matters, and it is not a weight — it is cooling capacity. HomeGuide gives the conversion: one ton equals 12,000 BTU and cools roughly 500 to 600 square feet, though it immediately adds that layout, ceiling height, insulation, climate and sun exposure all move that. Angi's national average across all sizes is $5,977, ranging from $1,400 to $12,500.
This page is general information, not professional advice. Prices move with your equipment, your region and the season, and the only number that counts is a written quote from a licensed HVAC contractor who has looked at your system.
2 ton, 3 ton and 4 ton AC replacement cost
| Tonnage | BTU | Unit price | 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 |
Source: HomeGuide
Read the unit column and the installed column together. The gap between them is roughly what the labor, the refrigerant, the electrical connection and the disposal of the old equipment cost, and it does not shrink much as the system gets bigger.
Average cost of AC replacement by efficiency
The SEER rating moves the number as hard as the tonnage does. HomeGuide publishes $5,300 to $7,900 installed at 13 to 14 SEER, $6,700 to $9,300 at 15 to 16, $7,500 to $10,600 at 17 to 18, $9,100 to $12,200 at 19 to 21, and $11,400 to $17,300 or more at 22 to 26. Federal minimums are 14 SEER in northern and southwestern states and 15 SEER in southeastern regions.
Source: HomeGuide
By system type rather than size, HomeGuide gives a central air conditioner at $5,300 to $10,500 installed, a central air conditioner with ductwork at $9,000 to $16,000, and a full HVAC system with a furnace and an air conditioner together at $10,500 to $18,500.
Source: HomeGuide
The furnace-and-air-conditioner version of this question has its own page, because it is a different product at a different price: what a full HVAC system replacement costs.
Cost to replace a central air unit: what is not in the number
Ductwork, first and always. HomeGuide footnotes every tonnage and home-size figure as excluding ductwork modifications or replacement, prices minor duct sealing and repairs at $300 to $1,500, and prices a full ductwork replacement at $1,400 to $5,600. ENERGY STAR says about 20 to 30 percent of the air moving through a typical duct system is lost to leaks, holes and poorly connected ducts.
Sources: HomeGuide, ENERGY STAR
- Permits. HomeGuide prices these at $100 to $250 for a replacement, and $250 to $1,500 for an installation involving ductwork.
- Electrical work. Angi says a new dedicated circuit runs $100 to $150 where the house does not already have one.
- A load calculation. HomeGuide lists a professional pre-install evaluation as an added upfront cost that ensures proper sizing.
- Season. HomeGuide says contractors discount in late fall and early spring, with May through August the peak.
When to replace rather than repair
HomeGuide publishes a list, and it is short enough to read in one go: uneven cooling or humidity problems, strange noises or odors, a system more than 10 to 12 years old, repairs costing at least 50% of a new AC, a system still running R-22 or R-410A refrigerant, steadily rising energy bills, or frequent breakdowns. It also says new units operate 20% to 40% more efficiently than 10-year-old models.
Source: HomeGuide
One trap worth knowing before you price a partial job. HomeGuide says you can replace only the outdoor unit if the indoor components are compatible and in good condition, but that a system running R-22 or R-410A cannot be half-replaced because of the refrigerant changes.
Source: HomeGuide
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Questions people ask next
- How much is a 3 ton AC unit replacement?
- HomeGuide publishes $5,800 to $7,800 installed for a 3 ton system, with the unit itself at $3,300 to $4,800. The installed figure is for a basic installation and excludes ductwork modifications or replacement.
- How much does a 2 ton AC replacement cost?
- HomeGuide publishes $5,000 to $6,800 installed for a 2 ton system, which it rates at 24,000 BTU. The next size down, a 1.5 ton, is $4,700 to $6,500 installed on the same HomeGuide table.
- How much does a 4 ton AC replacement cost?
- HomeGuide publishes $6,500 to $8,800 installed for a 4 ton system at 48,000 BTU. A 5 ton, the largest common residential size, is $7,000 to $9,500 or more on the same HomeGuide table.
- How long does a new central air conditioner last?
- HomeGuide says new AC systems last 15 to 20 years on average, and lists installation quality, maintenance frequency, usage patterns, environmental conditions and equipment quality as what decides where in that band a particular system lands.
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