Why Is My AC Blowing Hot Air?

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When the heat of summer begins to find its way into your home, it may be because your air conditioner is not working effectively. One common AC problem is hot air coming out of the vents.

We need our air conditioners working as well as possible in the summertime. We rely on the coolness of our home for comfort from the blazing heat. If your air conditioner is blowing hot air, you should address the problem as soon as possible.

5 Reasons Why AC is Blowing Hot Air

1. One reason your AC may be blowing hot air is that your thermostat is set to heat. This is the best case scenario if you notice warm air coming through the vents. The simple solution is to switch your thermostat to cool. Your thermostat may also need new batteries.

2. One common reason air conditioners blow hot air is low refrigerant levels. If you have low refrigerant levels, this means you leak. Simply adding more refrigerant will not solve the problem. You must get the leak fixed before you add more refrigerant. The problem may also be undercharged or overcharged refrigerant. To be safe, you should call a professional if you have a refrigerant problem.

3. Your AC could be blowing hot air because of a tripped circuit breaker. If the thermostat or refrigerant levels were not the problems, check the electrical panel your HVAC system runs on. Check for tripped breakers and blown fuses. A tripped breaker can be turned off and on again. A blown fuse must be replaced.

4. A dirty or frozen evaporator coil can cause your AC to blow hot air. An evaporator coil can get too clogged with dust and other debris that air can’t flow through. The reason your evaporator has build-up may be because your air filter needs replaced.

5. If the above reasons were not the problem, it might be a problem with the outdoor unit. Check the outdoor evaporator coils to make sure everything is working fine. Large items and debris could be clogging your evaporator coils, causing a halt in airflow.

How do I Fix my AC from Blowing Hot Air?

If your AC is blowing hot air, the first thing you should do is check that the thermostat is not set to heat. If it was set to heat, there is a simple fix. Switch your thermostat setting to cool. Also, check that the temperature is set low enough for your AC to kick on and that your thermostat has working batteries.

If your thermostat is working and that was not the problem, next check if the circuit breaker that your AC system uses is tripped. If this was the problem, flip the breaker off and back on. If the problem was a blown fuse, you must replace it to get your AC running again.

If a tripped breaker was not the problem, it is time to look at the evaporator coil. The evaporator coil should be located near the air handler next to the blower fan.

Evaporator coils absorb heat so that cool air can be circulated throughout your house. It is essential to keep these clean to ensure your AC runs efficiently and for a long time.

If you have a dirty or frozen evaporator coil, this can cause hot air coming from your AC system. If you suspect this is the problem, turn off your AC unit, then replace the air filter with a new one. A clogged air filter can cause build-up in your evaporator coil. Once the AC unit has thawed, turn it back on again. 

If this solved the problem and your AC is running efficiently, great! If replacing the filter with a new one did not fix your evaporator coil problem, you might have other issues, such as a refrigerant leak.

If the evaporator coils were not the problem in your AC blowing hot air, check your outdoor unit for a blockage in airflow. Outdoor evaporator coils can also get clogged with debris. Using a hose, you can rinse off the debris from your outdoor condenser unit.

If your AC system has low refrigerant levels, you have a refrigerant leak. This is a common reason AC units blow hot air. Check for ice on your refrigerant line. Don’t hesitate to call a professional and solve the problem as quickly as possible.

AC Maintenance Tips to Prevent from Blowing Hot Air

You can do certain things to maintain your air conditioning unit, including things you can do yourself and things you need a professional for. Regular AC maintenance helps your unit run as efficiently as possible, extending its lifespan and saving energy.

1. Change your air filter often. You should replace your air filter with a new one (or clean your reusable one) at least every 60 days. For the highest efficiency and the cleanest air, change your filters every 30 days. 

2. Clean your evaporator coils. Check your evaporator coils frequently to make sure they don’t have debris build-up. To clean your evaporator coils, turn your unit off and spray a commercial cleaner onto the evaporator coils to loosen the build-up. The build-up will drain away on its own. It may take more than one round of cleaner to remove all the debris.

3. Maintain clearance around the outdoor condenser unit. There should be at least two feet of clearance around your outdoor unit to ensure debris won’t clog the airflow. Check your outdoor unit frequently for debris and other build-ups. Remove larger items and spray off the dirt or leaves with a hose.

4. Schedule regular professional maintenance checks, tune-up, and cleaning. To get the most out of your AC system, it is important to get it checked out by a professional once a year. Getting your AC unit tuned up and cleaned will keep it running efficiently.

Other things you can do to maintain your air conditioning system include: keeping your thermostat above 72 degrees in the summer, so your AC doesn’t run non-stop, running ceiling fans to keep your home feeling cool and to give your AC a break, and keeping doors and windows closed to keep cool air in.

Don’t let your air conditioning run all day, every day. This can cause maintenance issues and waste a lot of energy. Set your thermostat to cool your house on “automatic,” not “on.” This can save you trouble in the future and help you save on your energy bill.

Hot air coming from your AC vents can be caused by various things such as a refrigerant leak, frozen evaporator coils, a tripped breaker or blown fuse, debris build-up in your outdoor condenser unit, or even a problem with the thermostat. 

Depending on what issue caused your air conditioner to blow hot air, you may not be able to fix the problem yourself. If you are not comfortable repairing your own AC unit, it is best to call a professional. You don’t want to risk breaking your system even further and causing more problems.

Discovering hot air blowing from your AC vents can be alarming. The solution to the problem can be as simple as switching your thermostat back to cool or as complicated as hiring a professional to look at the inner workings of your unit.