Is there anything more dismaying than turning on your AC on a blistering day and feeling warm or hot air coming from your return vents? This is one of the most common air conditioning problems we hear here at All Pro. If you’re struggling with an air conditioner that is blowing hot air, here are some possible causes and solutions for you to consider.

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6 Reasons Why Your AC Isn’t Blowing Cool Air

Incorrect Thermostat Settings

Make sure that your thermostat is set to “COOL” instead of “HEAT” (it may seem obvious, but trust us—it happens). Be sure to also select “AUTO” instead of “ON” so that your AC fan will only turn on when air is being cooled. If the problem persists, you may have one of the problems listed below, or you may potentially need to have your thermostat recalibrated or replaced.

Dirty Air Filter

Regularly replacing your air filter is one of the simplest things you can do to keep your air conditioner in good working order. If your AC is blowing warm air, there’s a good chance that a dirty, clogged air filter is to blame. Dirty filters restrict airflow and make your AC work harder than it should, consuming more energy while failing to deliver cool air. Dirty filters can also interfere with how your thermostat works and can lead to the formation of ice on your AC’s evaporator coils, which can be extremely damaging to your system. Be sure to change these filters out at least once every month or few months depending on the type of filter you buy.

Low Refrigerant

Refrigerant is the chemical that absorbs heat and humidity from the air. If your AC is low on refrigerant due to a leak, it won’t be able to cool the air. Resolving this problem is more involved than just adding more refrigerant, though; you’ll need a licensed AC technician to assess the condition of your system and determine whether the source of the leak can be fixed. If your AC still uses Freon, a type of refrigerant that has been banned, your old AC will probably need to be replaced.

Dirty Condenser Coils

Your condenser is the outside potion of your air conditioning system. Since it lives outdoors, it’s susceptible to the elements and can quickly become covered in dirt and debris. If the coils become too dirty and clogged, it can interfere with the performance of the system and cause the AC to blow warm air. The simple fix is to shut off the power and give the condenser a good clean. Remove as many leaves and other debris as you can by hand or with a shop-vac and give it a once-over with a soft bristled brush and/or a soft cloth.

Frozen Evaporator Coils

Believe it or not, your air conditioner can actually freeze on a very hot day, which can cause catastrophic damage to your system if ignored. If it’s an extremely hot day and your AC is running non-stop, you run a higher risk of a frozen air conditioner, especially if you’re lax on your AC maintenance. Dirty air filters are a common culprit in this situation because they restrict airflow and cause the evaporator to get too cold. If your AC is blowing hot air and you have noticed ice on your air conditioner, turn the system off immediately and call your local air conditioning repair company.

Leaking Air Ducts

If your air ducts are in bad repair, much of that cool air you’re paying for will end up escaping into your walls before it even makes it into your rooms. Since they’re out of sight, the only way to know if there’s something wrong with your air ducts is to have a qualified HVAC technician perform an inspection. If the inspection reveals a section of air duct that is cracked or disconnected, you’ll need to have it repaired.

You need a working air conditioner you can rely on as we head into another blazing San Bernardino County summer. If your AC is blowing warm air, don’t wait to call All Pro Plumbing, Heating, Air & Electrical at (909) 500-8193.