Sunny Windows, Shady Trees and Other Non-Electrical Supports to HVAC

When your central air conditioning unit is running, you expect to feel cold air coming out of your vents. But sometimes improper settings or failing parts can cause warm air to blow out your vents instead. If you recently experienced this hot problem, you can be reassured that the problem is likely only one of three possible causes – and one of those is extremely easy to fix.

Here are the most likely potential causes of a central air conditioner that blows out warm air and when you should leave the fix up to the ac repair professionals.

Thermostat Setting or Air Filter Issue

The first place to check is the easiest problem to fix. Make sure that your thermostat is set to cool instead of heat, which is a common mistake to make especially if you have children or guests. You want to also make sure the unit's fan is set to Auto and not On, which means the fan will run even when the unit isn't running. The fan could end up blowing out warm air when the main unit isn't running.

You also want to change out the batteries in your thermostat if they haven't been changed in the while. It doesn't matter if the thermostat seems to be operating properly. The failing batteries can cause glitches, such as improper temperature readings, before any visible problems occur.

While you are performing simple checks, take a look at your unit's air filter and clean or replace, if necessary. A blocked air filter can prevent enough cold air to come through your vents so the air can feel comparatively warm compared to the normal cold blast.

Compressor Issue

Thermostat and air filter check out with no problems? Time to head outside to the condensing unit to check on the compressor. Ask someone inside to turn on the unit at the thermostat when you walk outside. Listen for the sound of the unit kicking on and the fan speeding into motion.

Does nothing happen? Or does the unit kick on but quickly shuts back off? You might have a problem with your compressor.

The compressor receives the electrical signal from the thermostat then pumps out gas refrigerant that starts off the cooling process. If the compressor fails to start up or doesn't stay on long enough, then the system can't cool your air and the fan is likely just blowing recirculated warm air into your home.

Call in an HVAC service professional to check your compressor and its associated capacitors. The tech can replace parts where needed and get your unit back up and running quickly. Contact a business that handles AC repair for more information.