HVAC
How to Estimate a Central AC Replacement
Contractor method for estimating central AC replacement: size, SEER2, coil and refrigerant line.
Central AC bids fail on the indoor coil and the line set. The outdoor unit is the headline price; the coil, the line set and the refrigerant are where the quote runs over.
THE SHORT ANSWER
How do you estimate a central AC replacement?
Size by tons with a load calc, pick the SEER2 class (14/16/20+), then price the unit, matched indoor coil ($700-$1k), line set, removal and permits. A typical install runs $5,500-$14,000.
Size the system
Size by tons (2-5) using a load calc, not the old unit's rating alone. Oversized units short-cycle; undersized units run constantly. Note the SEER2 class — 14 standard, 16 efficient, 20+ premium.
Price the indoor coil
A matched coil runs $700-$1,000 and should be replaced with the outdoor unit for efficiency. Mixing old coil with new condenser is a call-back risk. Include the line set if the lines are old.
Price removal and permits
Removing the old system and reclaiming refrigerant runs $400-$600. Permits $350-$500. Use the Central AC Replacement Cost Calculator to build the full quote.
Check the total
Your total should land within 10% of the calculator output before markup. Note utility rebates and the 30% federal credit for eligible heat pump systems.