How do I know if I should repair or replace my AC?

The rule most HVAC technicians use: if the repair cost times the system's age exceeds the cost of a new system, replace. For example, a $600 repair on a 12-year-old system ($600 × 12 = $7,200) against a $5,000 replacement — replacement wins.

Age also matters independently: systems over 15 years old are significantly less efficient than modern units, and refrigerant for older R-22 systems is no longer manufactured and very expensive.

Vinson and Sill will always show you both numbers and let you decide.