Repair or replace your AC

First, the age

This Old House gives a home cooling system 12 to 15 years. The Department of Energy's Energy Saver guide is more conservative and says to start thinking about replacement after 10. Greenville owners should lean toward the DOE end, for a local reason: 84% of homes in the city heat with electricity (Census ACS 2020-2024), so the outdoor unit is usually a heat pump that works January mornings as well as July afternoons. Ten years on a heat pump here is more running time than ten years on an air conditioner in a gas-heated house.

Don't know the age? The data plate on the outdoor unit has a serial number, and the build year is usually coded into it. Photograph it and attach it to your request; the technician will read it for you.

Second, the size of the repair

Repair	Typical cost (Fixr, 2026)	On an old system
Capacitor	$100 to $400	Usually repair
Thermostat	$150 to $500	Usually repair
Refrigerant leak repair	$200 to $1,500	Depends on where the leak is
Evaporator coil	$400 to $2,700	Get a replacement price
Compressor	$600 to $3,000	Get a replacement price

To fold both numbers into one, use the $5,000 rule: age times repair cost, and anything over $5,000 means get a replacement price before you approve the repair.

Tiebreakers

• The service history. One repair is bad luck. A call every summer for three summers is a pattern.
• The refrigerant. Per EPA, R-410A systems remain repairable with R-410A parts, while equipment built from 2025 parts runs on lower-GWP refrigerants. An R-22 system is the expensive one to recharge. The refrigerant change.
• The feel of the house. If it's clammy at 75 degrees, the cause may be an oversized unit or leaking crawlspace ducts, and swapping a part won't touch that. When the house feels sticky.
• The GUC bill. A system rated at or above the 14.3 SEER2 Southeast minimum draws less power than an old low-efficiency one.
• Permits and credits. North Carolina requires a permit for a replacement, not for most repairs, and the federal 25C credit doesn't apply to equipment placed in service after 2025.

Where I'd draw the line

Under 10 years: fix it, unless it's the compressor. Over 15: I would not buy a compressor or a coil for it. I'd replace it on my own schedule, in April or October when installers aren't buried and a day without cooling is no hardship, instead of in the middle of a July failure.