Central AC Replacement Cost
National range, installed
$5,000 – $12,500+
3-ton, 15–16 SEER2 systems cluster around $7,000–$9,500. Ductwork extra.
What drives the price
| Driver | Impact | Notes |
|---|---|---|
| System size (tonnage) | +$800–$1,500 per ton | Must match a Manual J load calculation — oversized units short-cycle and mold |
| Efficiency (SEER2) | +$1,000–$3,000 per tier jump | 14 → 16 SEER2 is the common step; 18+ is premium with longer payback |
| Ductwork | $3,000–$7,000+ if replaced | Leaky 30-year-old ducts can waste 25%+ of cooling; get a duct test |
| Refrigerant & line set | $500–$1,500 | R-410A phaseout raised this; new line sets add labor |
| Electrical & permits | $300–$1,200 | Panel upgrades and local permits vary widely by municipality |
| Region labor | ±20–30% | Coastal metros run hot; rural South runs cheapest |
Repair vs replace
Use the $5,000 rule: multiply the repair quote by the unit's age in years. Over $5,000 — replace. A $900 repair on a 12-year-old unit ($10,800) says replace; the same repair at 4 years ($3,600) says fix it. Also replace when the unit uses phased-out refrigerant, needs its third major repair, or your summer bills keep climbing on the same thermostat.
Getting quotes that compare
- Demand Manual J in writing. Any contractor sizing by "rule of thumb" or matching the old unit is guessing. Load calcs take an hour and prevent a decade of regret.
- Compare identical SEER2 tiers. A cheap 14 SEER2 bid against a premium 18 SEER2 bid is not a comparison — normalize efficiency first.
- Ask what is excluded. Ductwork, permits, thermostat, disposal, and electrical are the classic exclusions that explode "cheap" bids later.
Quick answers
How much does it cost to replace a central AC unit in 2026?
Most homeowners pay $5,000–$12,500 installed, with 3-ton 15–16 SEER2 systems around $7,000–$9,500. Ductwork adds $3,000–$7,000+.
Is a higher SEER2 rating worth the extra cost?
In hot climates with 5+ months of cooling, jumping from 14 to 18 SEER2 typically pays back in 6–9 years. In mild climates, buy mid-range — the payback often exceeds the unit's life.
Before you sign: read our contractor quote guide — allowances, vague line items, and deposit terms are where AC quotes hide surprises.