What To Do When Your AC Unit Starts Blowing Warm Air

Does Your Home Need a Breath of Fresh Air? These Tips Can Help

What To Do When Your AC Unit Starts Blowing Warm Air | It is a simple fact of life that things tend to go wrong when they are needed the most. Your air conditioning unit is a perfect example of this, it is most likely to fail on the hottest day. Of course, speaking to your local air conditioning sales specialist will help as they can arrange regular maintenance and reduce the risk of problems arising.

While the best course of action is to call a specialist and have them investigate why your air conditioning unit is blowing warm air, there are several things you can check yourself. That doesn’t mean you have to fix the issue but you will at least be able to identify it.


The thermostat controls the air temperature. Check yours to make sure it hasn’t been accidentally knocked and not telling the unit to produce very cold air. 

If you turn the thermostat you should hear it click. This is the temperature it thinks the room is at. Turning it down to a cooler setting will lower the temperature of the air from the unit. If you turn it to the lowest setting and wait a couple of minutes you should be able to feel the air blowing cooler. If it doesn’t it could be a thermostat fault. 

Dirty Coils

The evaporator and coils suck the warmth from the surrounding air. If these are covered in dirt and dust the fluid in the evaporator will stop moving and it can freeze. This doesn’t equate to cooler air. It does mean that the air cannot be cooled and the motor may warm excessively, potentially creating additional problems.

Cleaning the coil regularly prevents this. It is also a good idea to change the air filter regularly as this prevents most of the dirt and debris from getting to the coil. However, if they are already frozen you need to get a specialist to help you defrost them and check the system before using it.

You should note that there are usually coils inside and outside your home. Check both are clean to ensure you have eliminated this potential cause of warm air.


Your air conditioner uses refrigerant. This is a specialized liquid inside the unit that helps cool air. It is under pressure but one of the most common AC issues is a leak in this part of the system. If there isn’t enough refrigerant, the unit will not be able to produce cold air properly. Alongside blowing warm the unit may make gurgling or hissing noises.

Refrigerant is pressurized and dangerous, only a technician can resolve this issue for you. However, a tune-up before you start using the system can help to prevent leaks from being an issue.


Your air conditioner may be incorrectly sized and working too hard to cool the space inside your home. This can result in excess strain on the unit and an inability to cool the air properly. You will need a second unit or to replace it with a larger unit to eliminate this issue.