Why Is My AC System Blowing Hot Air?

Dirty Air Filters

All of the air that comes through your HVAC system passes through any air filter. In order to keep these filters clean — and the air you’re breathing fresh — these air filters need to be routinely cleaned or replaced.

One sign that your air filter is dirty or blocked can be hot air. That’s because the air is unable to properly move through the dirty filter, putting strain on your AC unit and causing it to blow warm air. Start with having your air filter replaced.

Frozen Coils

The evaporator coils in your HVAC system helps absorb heat from the air in the compartment. A byproduct of this process is condensation, which should be collected by a drip pan and drain in your system. But if that moisture starts to collect on the coils, it can freeze and prevent that heat from transferring, causing the air to blow out hot instead of cool. Once you get this problem fixed, your AC unit will go back to producing cool air.

Incorrect Thermostat Errors

Is your thermostat set to “heat” instead of “cool”? Warm air coming from your AC unit might be as simple as an incorrectly set thermostat. Take a look at your system’s settings and see if an incorrect setting could be to blame for the warm air.

Not Enough Electricity

You seem to have power to your home, so your first thought when you feel warm air blowing from your AC unit might not jump to an electrical problem. But just because your HVAC unit has enough power to operate doesn’t mean that it’s not short on power.

HVAC systems have both an indoor and outdoor component. If that outdoor component loses power but the inside one doesn’t, your indoor unit will still be blowing air through your vents but it will be warm air instead of cool air. Check that both your indoor and outdoor units are getting power.