IQHab › United States › HVAC › AC Not Cooling — What To Check
AC not cooling
Your AC is running but the house isn't getting cooler. The cause is usually simple — and often fixable before you call a pro.
Likely causes
| Cause | Likelihood | Severity | Cost |
|---|---|---|---|
| Dirty air filter | high | Low | $0–$25 |
| Low refrigerant / leak | medium | Medium | $200–$1,500 |
| AC capacitor or contactor | medium | Medium | $150–$400 |
| Thermostat issue | medium | Low | $50–$300 |
| Compressor failure | low | High | $1,500–$3,000 |
Safe checks you can do
- Check that the thermostat is set to cool and the fan is on auto.
- Replace or clean the air filter if it's clogged.
- Make sure the outdoor unit isn't blocked by debris.
Emergency signals
- Ice on the refrigerant lines or indoor coil
- Burning smell or unusual noises
- Warm air even with a clean filter and correct settings
Next action
If the filter is clean and settings are correct but it's still not cooling, book an AC service call. If you see ice, a burning smell, or hear loud noises, call an emergency HVAC technician now.