AC Blowing Warm Air? What It Means
Warm air from the vents usually means the outdoor unit is not removing heat, or the system is not set to cool.
Common causes
Thermostat settings
The fan may be set to On while the system is not actually cooling, or the mode is wrong.
Outdoor unit not running
A failed capacitor, contactor, fan motor or tripped breaker can leave the indoor fan blowing unconditioned air.
Frozen coil
Ice can block heat exchange and cause warm or weak air.
Low refrigerant or a leak
Without enough refrigerant, the system cannot absorb heat.
Compressor problems
A failing compressor may run without cooling effectively.
Heat pump in the wrong mode
A heat pump stuck in heating mode or with a reversing valve problem can produce warm air in summer.
What you can safely check
- Confirm the thermostat is on Cool and the fan is set to Auto.
- Check your breaker panel for a tripped breaker for the AC.
- Check the filter.
- Look for ice on the indoor unit.
When to call a professional. If the outdoor unit is silent, the breaker trips again, or the air stays warm after a filter change, call a technician. Never open electrical panels or remove access covers on equipment. If you smell burning or see smoke, turn off power and call 911 if there is any danger.
Why is my AC blowing warm air but running?
The indoor fan can run even if the outdoor unit has failed. Check the thermostat and breaker, then call a technician if air stays warm.
Is warm air from the vents dangerous?
The air itself is not, but the underlying cause may be an electrical or refrigerant problem that should be repaired promptly.
Could my heat pump be stuck in heating mode?
It is possible. A technician can check the thermostat, reversing valve and controls.
Next steps and related help
Comfortable again, without the runaround
$30 off your first service call. Mention this website when scheduling. Cannot be combined with other offers. Excludes diagnostic fee and maintenance visits.