AC Not Blowing Cold Air
If the indoor fan blows but the air isn't cold, go outside: if the outdoor unit is silent or just hums, a failed capacitor or contactor is the most common cause. Capacitor replacement typically costs $100–$400 (around $175 on average), and a contactor $150–$400.
Last reviewed September 2026
Troubleshoot it now
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Check the thermostat and breakers
Set cooling a few degrees below room temperature. Check the breaker for the outdoor unit and the disconnect switch next to it; reset a tripped breaker once.
Signs it's this problem
- Vents blow air, but it isn't cold
- The outdoor unit is silent or makes a humming sound
- The outdoor fan doesn't spin, or spins slowly
- A tripped breaker or blown fuse for the outdoor unit
Why it happens
The outdoor unit holds the compressor and fan that actually remove heat. The capacitor gives them the jolt to start, and the contactor switches power on. Heat and age wear both out, and when they fail the indoor fan still runs, so the vents blow room-temperature air.
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Safety: Capacitors store a dangerous electric charge even with the power off. Don't open the outdoor unit's electrical panel; leave testing and replacement to a technician.
AC Not Blowing Cold Air cost
| Job | Typical cost |
|---|---|
| Replace a capacitor (average about $175) | $100–$400 |
| Replace a contactor | $150–$400 |
| Typical AC repair (average about $350) | $150–$650 |
Got a quote? Check if it's fair
Typical professional price for this job: $100–$400
Common questions
Why is my AC fan running but not cooling?
The indoor fan can run while the outdoor unit is off. A failed capacitor, contactor, tripped breaker or a compressor problem leaves the system blowing uncooled air.
Is a bad capacitor expensive to fix?
Usually not. The part is cheap and replacement is one of the most common, least expensive AC repairs, though a failing capacitor left too long can strain the compressor.