Quick answer: replacing an AC capacitor costs about $100–$450 installed, parts and labor, across three 2026 price guides. It's one of the cheapest and most common AC repairs.
What the price guides say
| Source | Installed price |
|---|---|
| Fixr (updated January 2026) | $100–$400 |
| This Old House (updated March 2026) | $150–$400 |
| PickHVAC (May 2026) | $120–$450, average $250 (capacitor or contactor, with 1–2 hours of labor) |
Nights and weekends cost more: Fixr puts emergency labor at $150–$300 an hour. The cost estimator can add that for you.
What a capacitor does
A capacitor stores an electrical charge and gives the compressor and the outdoor fan motor the push they need to start and keep running. When it weakens or fails, the motors struggle or don't start at all.
Signs the capacitor has failed
- The outdoor unit hums but the fan doesn't spin
- The AC runs but blows warm air
- Clicking from the outdoor unit as it tries to start
- The system shuts off on its own, or takes a while to start
These overlap with a failed contactor (about $75–$450) and, less often, a failing compressor, so let the technician test before replacing parts.
Why it's a job for a technician
A capacitor can hold a dangerous electrical charge even after the power is off. Leave the outdoor unit's panels closed and let a technician test and replace it.
Savannah's coastal air
HVAC Project Cost says salt from the Atlantic and the marshes settles on outdoor HVAC parts, including capacitors, and speeds up wear. A yearly tune-up includes checking the electrical parts, which can catch a weak capacitor before it fails on a hot afternoon.