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Why Is Your A/C Unit Blowing Warm Air

It has to be one of the worst realizations ever.  You’re waiting to reach that comfortable temperature to cool you down from either exhaustion, summer heat, or being out in the sun.  The fan has been blowing for a while and dang it, it’s just not getting comfortable so you put your hand in front of the vent and, hot air?  What a bunch of malarkey!

Dealing with this scenario is incredibly annoying. When your A/C unit blows warm air it really brings out the heat from within (if you catch the drift), especially when the sweat is pouring down your forehead while you fiddle with the thermostat.  When you can’t cool down it can be a real mood-swinger. Why is this happening to you? Here’s are a couple of reasons why it could be happening:

Thermostat Setting:

Make sure you check the batteries in your thermostat.  If the batteries are low, the signal going to your air conditioner can get lost.  Sometimes it’s as simple as making sure the settings are not warm or hot and instead set to cool or cold.  If the button breaks, time to get a new Thermostat. If you know the thermostat is working exactly how it’s supposed to, the malfunction can be an electrical issue.  Your thermostat might be hooked up to a circuit that’s been tripped. Check your panel box.


With all the electrical wiring hooked up to the outside unit, outside forces of nature may have had a hand in your issue.  If critters are living close by or even stray animals are lurking around, they may have chewed on the wiring. This isn’t always a typical issue, but it’s common enough to check your outside unit for ‘fowl’ play.


Compressor failure can be caused by a few issues such as electrical failure, refrigerant coming back instead of going to the evaporator, or possible overheating.  The compressor is like the engine of the air conditioner unit. If it fails everything else is bound to follow. If the compressor cannot be repaired, the better option is replacing the entire unit.

Dirty Condenser:

Because your condenser releases heat from your home or if the coils on your condenser clog up and/or build up with debris, the warm air won’t be able to escape.  Check to see if you find build up or residue that looks like it shouldn’t be there.

Dirty Air Filter:

Debris, dust, leaves, and any other outside elements that could potentially clog up your filter may be filling up all possible ventilation.  Think if you never emptied your clothes dryer vent and left all the lint built up in there. Your clothes would never dry. Nobody wants a soggy outfit… unless you’re a scuba diver.  The same goes for air circulation and filters. Change your filters regularly.

Refrigerant Leak:

It’s possible you have a leak in your refrigerant line.  Freon is added to this line which gives your air conditioner cooling power.  If there is a leak and your ac is blowing warm air, before you add more freon (which is a whole other issue you need to be aware of) you need to patch the leak.  A professional would be the best option for this repairing. It’s also important to note that Freon is being phased out for all types of air conditioners at the beginning of 2020.  For more on that, read about the Freon Phase Out.

Your cooling line could also have a joint loose, either because of poor manufacturing or over time during usage and weather, wear and tear start to take hold.  Refrigerant leaks are unpredictable and usually not very common, but when they do arise they should be dealt with immediately.

Leaky Air Ducts:

As we have said in many of our Accurate blogs before, leaky air ducts have a tremendous effect on the efficiency of your HVAC system.  If you do have leaks within your air ducts then you could have an ac blowing warm air. Check your outside unit and your electrical system, but don’t rule out the possibility of warm air coming in thanks to damaged, dirty or worn air ducts.  

If you find your ac blowing warm air, instead of kicking the wall or yelling at the thermostat use the list provided above.  Do a thorough check to make sure everything is functioning normally. If you’ve had prior problems or a history of malfunctions with your air conditioner, you may want to think about the future.  We can help.