Central AC System GuideReplacing a central air conditioner is a large home project, and the price swings widely with the equipment and the home. Fixr reports a standard replacement range of $5,500 to $10,000, while HomeAdvisor puts professional AC installation between $3,887 and $8,073. The spread reflects tonnage, efficiency rating, and labor more than anything else.
The headline replacement range
Replacement cost depends heavily on which reference you read and what scope it assumes. Fixr lists a standard central AC replacement at $5,500 to $10,000, and a broader installed range of $5,800 to $14,400 with an average near $8,750 once ductwork and home size enter the picture. HomeAdvisor reports a tighter professional installation band of $3,887 to $8,073 with an average around $5,977.
The gap between these figures is normal. A straight swap of the outdoor and indoor units on existing, healthy ductwork sits at the low end, while a higher efficiency system, added ductwork, or difficult access pushes toward the high end. Present the range as a range, not a single number, until a contractor performs an in-home assessment.
Unit size drives the biggest jump
Cooling capacity, measured in tons, is the single largest cost lever. Fixr prices an installed 3 ton system at $5,000 to $9,150, a 4 ton at $6,950 to $11,600, and a 5 ton at $7,800 to $14,000. HomeAdvisor breaks out the equipment alone, listing a 2 ton unit at $1,500 to $5,000, a 3 ton at $2,000 to $5,500, and a 5 ton at $2,800 to $6,800.
Bigger is not automatically better. Sizing should follow an ACCA Manual J load calculation rather than a blanket rule, since an oversized unit costs more up front and cools less comfortably. The tonnage you actually need is the one that matches the home's calculated load.
Efficiency rating changes the ticket
A higher efficiency system costs more to buy but less to run. For a 3 ton unit, Fixr prices a 14 SEER system at $1,725 to $3,600, a 16 SEER at $2,875 to $6,000, and a 20 SEER at $5,750 to $9,600. HomeAdvisor notes only that higher SEER units cost more up front while lowering long term energy bills.
The federal government frames the trade in payback terms. The Department of Energy Federal Energy Management Program reports that an ENERGY STAR model pays off in hot-humid states if it costs no more than $1,853 in 2023 dollars above a less efficient model, and that the best available models can save up to $6,724 over their lifetime.
Labor and installation scope
Labor is a meaningful slice of a replacement. Fixr puts installer rates at $75 to $250 per hour and split system labor at $1,250 to $3,000. HomeAdvisor lists $75 to $200 per hour for a job that usually takes four to eight hours, for total labor of $300 to $1,600.
Scope beyond the equipment matters too. Fixr expresses whole-project pricing as $2.90 to $7.20 per square foot of conditioned space, which captures the effect of home size, ductwork condition, and access. A replacement that requires new ducts or electrical work lands well above a like-for-like swap.
Tax credits and the post-2025 caution
Federal incentives can offset part of a high efficiency replacement, but the rules changed for work done after 2025. ENERGY STAR states that qualifying split systems must meet SEER2 of 17.0 or higher and EER2 of 12.0 or higher, packaged systems must meet SEER2 of 16.0 or higher and EER2 of 11.5 or higher, and the credit equals 30 percent of project cost up to $600, claimed on IRS Form 5695. That same page describes the credit as effective for products purchased and installed between January 1, 2023 and December 31, 2025.
Because the 25C energy-efficient home improvement credit changed for improvements placed in service after 2025, do not treat any current percentage or cap as settled for a job done now. Confirm the current status directly at IRS.gov or energy.gov before promising a homeowner any credit.