Imagine the scene; you get in from work after a long hard day and a hot, sweaty commute, turn on the air conditioning, settle back in your favorite chair and feel the temperature RISING, not falling. You immediately check the thermostat setting, it’s normal. You check the system setting, it’s on cool, not heat. Then you check the air coming out your vents and it is warm. The awful truth hits you, your AC is blowing hot air, not cool.

Not very pleasant is it, but it can happen. Here we’ll look at the various reasons why you might find your air conditioner blowing warm air.

Common causes of AC blowing hot air

Basically, if hot air is coming through your vents while your AC is on and in cooling mode, there is something causing the cooling mechanisms to malfunction. It could be something simple, like the thermostat setting, but it could also indicate that there are bigger issues with your system, such as a refrigerant leak.

If it’s an easy fix, you might be able to deal with it yourself, for something more serious you’ll need to call in the professionals. Below we’ve listed the most common causes of an AC blowing warm air, ranked in order from least to most serious.

  • The thermostat wars
    Whether at home or at work, it can be hard to find a thermostat setting that everybody who uses the space is comfortable with. This can lead to family members or coworkers making sneaky adjustments to the thermostat settings. This can also happen by accident if the thermostat gets bumped accidentally. So, the first thing to do with an air conditioner blowing hot air is to check the thermostat settings.
     air conditioner blowing warm air
  • Clogged filters
    This is one of the most common (and most easily preventable) causes of ACs not cooling properly. Your system needs an intake of air to function properly. If no air can get in because the intake filters are clogged with dust and debris, it won’t be able to cool properly and will blow warm air back through the system.
  • Blocked or closed vents
    If you’ve recently had your home or workspace remodeled, or rearranged the furniture, you might have blocked a vent, restricting the airflow in the system. Check that all your vents are open and free of obstruction.
  • Ductwork issues

    If your ductwork has sprung a leak, or parts of it have been blocked off during remodeling, your supply of life-giving cool air might be leaking away into your crawl spaces and attic. Your ducts may also be blocked by animal or bird’s nests or other debris. This is a good time to start thinking about bringing in the professionals.

  • Coated condenser coils
    Your condenser coils are responsible for releasing heat to the outside. But, as they are in the outside unit of your system, they can get dirty. If they become coated in dirt and grime, they won’t be able to do their job. Condenser coils are quite delicate and easy to pierce, so it’s better to seek professional help cleaning them.
  • Refrigerant leak
    Refrigerant is a liquid gas that circulates through your system and removes heat. It flows through a closed circuit and the level should remain constant during the lifetime of your unit. If you do spring a leak, your system will lose its cooling power over time. The speed this happens will depend on the size of the leak. If you think this could be the issue, call your repairman immediately. And while we are on the subject of refrigerant, if your AC is ten or more years old, you might want to read this article.

We hope you found this blog informative and remember, prevention is better than cure, so contact us now to schedule a maintenance check for your system and avoid having to call us out for an emergency visit.