There are several reasons for your AC to be blowing warm air instead of cool air. We recommend following the following steps:
First, check your thermostat. It sounds silly, but it is fairly easy to accidentally bump into the thermostat and set it to blow warm air instead.
If your thermostat is fine, then check to make sure that your outside unit is getting electricity.
If a circuit has been blown or tripped, it can cause the AC to stop; if that is the case, it is always best
to get a trained electrician or HVAC provider to take a look at it as a tripped or blown circuit could point to a more serious issue.
If your air conditioner is getting plenty of electricity then it’s possible that the coils have frozen – while it seems counter-intuitive to blow warm air when frozen, this means that your air conditioner is blocking the cool air from getting through to the fan. If you check your AC and see that it has frozen, turn it off for a few hours and turn it back on again. By then it should have melted and should be offering you cool air again.
If, however, your air conditioner continues to blow warm air, then call in a professional to take a look at it. There could be much more than just freezing coils going on.
If your coils are fine, the thermostat is fine, and there is electricity going through to your outside unit, check to make sure that your AC has a clean filter. While this doesn’t account for all the problems that could cause warm air to come out of your AC, it can inhibit the cool air from exiting.
Make sure to have your air conditioner serviced on a regular basis by a professional and change out your filters on a regular basis as well to ensure that your HVAC unit is working properly.