The Five Factors
1. System condition
A well-maintained system with one failed part is a repair candidate. A neglected system with multiple worn components is a money pit with a fan. Condition beats age as a predictor, which is why inspection comes first.
2. Repair scope
Capacitors, contactors, fan motors, and thermostats are modest repairs on almost any system. Compressors and evaporator coils are major repairs whose cost approaches a meaningful fraction of new equipment. Scope reframes everything: the same system can be an obvious repair or an obvious replace depending on what failed.
3. Equipment age
Central air conditioners commonly serve 12 to 15 years with maintenance. Under ten years old, repair is usually the default. Past fifteen, replacement deserves serious weight in every major-repair conversation. Between those marks, the other four factors decide.
4. Efficiency
Older systems run at efficiency ratings well below current equipment. The gap matters more the more you run the system, but be honest with yourself about the math: no contractor can truthfully guarantee specific savings, and payback periods depend on your usage and rates.
5. Replacement cost and parts availability
Get the actual numbers: the written repair quote and a written replacement quote for comparable equipment. Some older systems also face parts scarcity, and systems using phased-out R-22 refrigerant face refrigerant costs that change the economics of any leak repair.
The Informal Check (Not a Rule)
Multiply the repair cost by the system's age in years. If the product exceeds the price of a new system, replacement usually deserves the nod. A $400 repair on an 8-year-old system ($3,200) against a hypothetical $5,000 replacement argues for repair. A $1,200 repair on a 14-year-old system ($16,800) argues the other way. Use it to structure the conversation, not to replace it.
Questions That Expose Bad Advice
- "What exactly failed, and can you show me?" A contractor who cannot name and show the failed part has not diagnosed anything.
- "Is this failure isolated, or a symptom of broader wear?"
- "What would you do if this were your house, and why?"
- "Can I have both quotes in writing?"
Be wary of replacement pitches made without inspection, and of repair pitches on systems that are clearly at end of life. Both patterns cost you money.
Next Steps
The AC repair and AC replacement pages go deeper on each path. When you are ready for real numbers, call (515) 724-6446 to connect with an independent contractor, and verify licensing and insurance before authorizing work.