The quick math: the $5,000 rule
Multiply the system's age by the repair quote. Over ~$5,000, lean replace; under, lean repair. A $400 capacitor on an 8-year-old unit (3,200) is a clear repair. A $1,200 coil on a 14-year-old unit (16,800) is throwing good money after old equipment. It's a heuristic, not gospel — but it forces age into the conversation, where it belongs.
Age and failure type matter more than the number
- Under 10 years: repair almost everything except a failed compressor — and check your warranty first; many parts warranties run 10 years if the unit was registered.
- 10–15 years: repair cheap electrical parts (capacitors, contactors, fan motors). Think hard on refrigerant-circuit repairs (coils, compressors) — they're the expensive organs.
- 15+ years: any four-figure quote should trigger replacement quotes alongside repair quotes.
The refrigerant transition changes the math
The industry is moving to new lower-impact refrigerants, and older refrigerants get pricier as supplies tighten — which quietly inflates the cost of keeping an aging system alive. Big refrigerant repairs on older systems increasingly mean paying premium prices for yesterday's technology. Ask any quoting tech what refrigerant the repair uses and how its price has trended.
Efficiency: the part of the math everyone skips
A 15-year-old system typically runs far less efficiently than a new high-SEER2 unit — both from technology and from age-related decline. If your summer electric bills are painful, fold the monthly savings of a new unit into the comparison, and check the ENERGY STAR rebate finder plus federal tax credits for efficient equipment before pricing the new option at sticker.
Get a plan for your exact situation
The free FixAC First-Aid wizard turns your symptom, system age, and ZIP into safe step-by-step checks — plus a briefing on what a fair repair should cost.