Have you ever turned on your air conditioner, only to discover that it isn’t blowing cold air? If you have, you’re not alone. An air conditioner not blowing chilly air can be an unpleasant surprise for homeowners, but it’s also a fairly widespread problem. However, there are numerous probable causes for warm air blowing from your AC, and many of them can be problematic if you don’t address them quickly. To help you determine the cause of the trouble, we’ve come up with a list of seven reasons that could account for why your AC isn’t blowing cold air the way it should be.

The Seven Most Common Reasons for an Air Conditioner Not Blowing Cold Air

air conditioning not blowing cold

When cold air is absent, check these areas in the following order:

  • The Thermostat: believe it or not, but a disproportionate amount of air conditioner “problems” are nothing more than incorrect thermostat settings the owners haven’t noticed. A thermostat is like the brain of the air conditioner: the rest of the system does what the thermostat tells it to do. If the thermostat is set to a hotter temperature than you want, you’re going to feel warm air coming out of your AC. Always check the thermostat before looking at any other part of your system.


  • The Filters: one of the next leading causes of AC trouble is dirty filters. Clean filters prevent dust and other unwanted foreign matter from coming into your system where it can congeal in the ducts and eventually cut off airflow. Reduced airflow will limit the system’s ability to pump cool air throughout the space, so make sure that you always check your filters and replace or clean the dirty ones on a monthly basis.


  • The Coils: dirty ducts can lead to another problem: dirty evaporator coils. When evaporator coils become too dirty, they tend to freeze over and prevent your system from completing the cooling process. If enough dirt becomes lodged in the ducts through the filters or return vents, you may find yourself dealing with dirty coils as a result. You can check the coils by opening the indoor unit, which should be located slightly above the furnace in most home HVAC systems. However, do not attempt to clean the coils yourself. A licensed HVAC technician should always handle the process.


  • The Fuse Box: the outdoor unit is just as important to the cooling process as the indoor unit is, but it cannot function without a steady supply of electrical power. If there is a problem with the fuse box in your home, the outdoor unit may not receive the necessary energy to work correctly. A breaker flipped the wrong way can be switched back on quickly, but only a licensed electrician should ever handle problems with fuses or wires. Contact your HVAC service company and have them advise you on the next steps you should take.


  • The Refrigerant: refrigerant is the lifeblood of an air conditioner. If enough of it does not flow through the system, the air conditioner will be unable to function. When refrigerant leaks from an air conditioner, the cooling process becomes impossible. The air conditioner blower fan continues to circulate air throughout the ducts, but this air has not been treated and remains as warm as the air that comes into the system in the first place. If you notice liquid of any kind leaking from your air conditioner, call a professional immediately. Refrigerant is a chemical that should only be handled by those who have proper training and experience.


  • The Return Vents: return vents collect treated air from inside your home and recirculate it throughout the system. However, a broken return vent may allow air to enter the system from untreated areas—such as attics, crawl spaces, or the outside. If you have examined the areas mentioned above and found no apparent signs of trouble, there may be a problem with the return vents. If that is the case, you should contact a professional and have them conduct a thorough investigation of your system to determine whether the return vents are functioning correctly or not.


  • The Compressor: compressor failure is usually the result of other problems that have been left unchecked for too long. The compressor in your air conditioner can fail for numerous reasons, but when it does, it will immediately cause your system to stop working as it should. Without a compressor to force the refrigerant in the AC to change states, the cooling process becomes impossible. The best way to deal with compressor failure is to avoid it entirely—have your HVAC service company perform annual maintenance on your system and take diligent care of it if you want to prevent this costly problem.


The seven problems listed above account for nearly every instance of an air conditioner not blowing cold air. If you are having this problem with your AC, check the first four items on the list by yourself and call a professional to inspect the rest.

Check with us here at Valley Comfort Heating and Air, our customers love our attention to detail and our friendly, affordable service. (707) 800-6287