When an AC runs but is not cooling, the most common causes are a dirty air filter, a frozen evaporator coil, a dirty outdoor condenser, low refrigerant from a leak, a failed capacitor, or a thermostat set wrong. Replace the filter, set the thermostat to cool and a lower temperature, and clear debris from the outdoor unit; if it still blows warm air or the coil is iced, call for same-day AC repair before the system is damaged further.
Common causes
- Dirty or clogged air filter
- Frozen evaporator coil (turn the AC off to thaw)
- Dirty outdoor condenser or blocked airflow
- Low refrigerant from a leak
- Failed capacitor or contactor
- Thermostat set to the wrong mode
What to try, and when to call us
- Replace the air filter if it is dirty
- Set the thermostat to cool and lower the temperature
- If the coil is iced, turn the AC off and the fan on to thaw
- Clear leaves and debris from the outdoor unit
If it still blows warm air, trips the breaker, or freezes again, call First Response for same-day AC repair across San Antonio, 24/7.
Frequently asked questions
Why is my AC blowing warm air?
Common reasons are low refrigerant, a frozen coil, a dirty condenser, or a failed capacitor. We diagnose it on-site the same day.
Should I keep running it?
If it is frozen or blowing warm, turn it off to avoid compressor damage and call us.
How fast can you come?
AC failures in San Antonio heat are emergencies; we dispatch same day, 24/7.