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Why Is My Air Conditioner Blowing Warm Air?

We all know that in Texas our air conditioners are essential most of the year, so when you have an AC not working you need a solution fast. Luckily, Mission AC knows HVAC systems inside and out, and we’re here to help you get your cooling system back in working order as quickly as we can. 

One of the most common problems AC systems have is when they start blowing warm air. If your AC is blowing warm air, or ever has, we have several reasons and solutions that might help you out.

5 Common Causes of Warm Air From Your AC

Though there could be many causes of warm air from your AC we have the most common listed here. There are even some that homeowners can assess and possibly resolve on their own!

Thermostat Settings

Though it may seem silly, an honest mistake when setting your thermostat could leave you with warm air blowing in your home. If the fan is set to ON instead of AUTO then the fan will continuously blow even when the system is not cooling. This means the fan will simply blow the warm air from the ducts out through the vents.

Check your thermostat to make sure AUTO and COOL are selected so that your system is cooling the air and will only blow the cooled air out of the vents.

Air Filters

Maintaining the air filters in your AC system is very important. One unfortunate consequence of not cleaning air filters can be warm air blowing from your AC. Dirty filters don’t allow the AC system to filter and move air efficiently which puts a strain on your unit. This can cause warm air flow throughout your home.

Checking your AC air filter is usually a simple job. If the filter is covered in dust and debris, change it out for a new filter to see if this resolves your warm air problem. Make sure you know the right size and thickness of your filters before buying new ones!

Electricity Interruption

If you have a split system AC unit, both the indoor and outdoor parts of the system need to be functional to complete the cooling cycles. An interruption in power to the outdoor unit causes the cooling components housed in that part of the system to not run. This can cause warm air to be circulated by the indoor air handler. 

Double check that your outdoor unit has electricity. Locate the electrical panel for your home and ensure no breakers have been tripped – reset any as needed. You can also find the ON/OFF switch for the outdoor unit itself and make sure that is ON. 

Evaporator Coils Are Frozen

The evaporator coils in your AC unit are designed to start the cooling process of air by absorbing heat. During this process condensation forms – thus a drip pan and condensate drain to remove the moisture from the unit. However, if the condensation does not get entirely removed it can freeze on the coils. If the coils are frozen the air can’t be cooled and may blow warm out of the vents.

If you’d like to check on this problem yourself, power down your entire system and find the access panel on the outdoor unit. This panel gives you access to the inside components, including the evaporator coils. If the coils look icy they must be thawed – this can take up to 24 hours if the freeze is severe. Do not turn your AC back on until they are thawed.

You can try to speed up the process with a heat gun or hair dryer carefully aimed at the coils. Double check that the drip pan and condensate line are open so that the melting water can be drained from the system. 

If you’re unsure about opening up your AC unit or thawing the coils, a technician will be happy to help. The causes of frozen coils are often damage or leaks that must be repaired by a licensed technician anyway, so they can thaw the coils and also assist you in finding a solution to keep the coils from freezing again. 

Leaking Refrigerant

Refrigerant in your unit is what allows the air to be cooled before it’s delivered to your home. If the refrigerant is leaking, then the air cannot be cooled and the fan is blowing warm out of your vents.

Refrigerant leaks must be fixed by licensed professionals who are certified for refrigerant handling. Other signs that commonly signify a refrigerant leak include:

  • Frozen evaporator coils (mentioned above)
  • Abnormal noises from the outdoor AC components
  • Sudden increases in electric bills

Ready For Cool Air Again?

At any time during the process of identifying a problem in an AC or attempting to fix an AC blowing warm air, feel free to use Mission AC repair services. Our team of highly experienced HVAC professionals is the best Houston air conditioning repair company to ask for help! Give us a call today!

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