When summertime temperatures begin to soar and your air conditioning system gets pushed to the limit, this increases the likelihood that your AC system will experience some kind of breakdown that calls for repairs. One of the most common conditions that may occur due to a stressed air conditioner is that it begins to blow warm air.
There are a number of troubleshooting steps you might take before calling your preferred HVAC contractor to come in and fix the problem. Let’s take a look at some of the reasons your air conditioner may be blowing hot air.
Clogged Air Filters
Whenever your cooling system has a dirty filter, it will be impossible to have proper airflow through the system, which can put a major strain on your air conditioning unit. If the filter is clogged badly enough, it can definitely cause your AC unit to blow warm air. This is the very first check you should make when you’re troubleshooting a cooling system that is issuing warm air. If you discover that the filter is indeed clogged with debris, you should either clean the filter or have it replaced entirely.
Evaporator Coils Are Frozen
The evaporator coils on your air conditioning unit serve the function of extracting heat from your interior air in order to begin the cooling process. One by-product of this process is condensation, and that’s why you’ll find that air conditioners have a condensate drain and drip pan which catches the extracted moisture and removes it from the system.
When moisture begins to collect on your evaporator coils, it’s possible that they can freeze up. When this happens, heat transfer is prevented, and the result is that you will feel warm air blowing from your air conditioner. You can check to see if this is the problem by shutting off the power to your cooling system and opening the access door so you can see the evaporator coils.
If there is frost or ice present on the coils, your best bet is to allow them to thaw out, although that may take as long as 24 hours. You might also want to expedite the process by using a hairdryer to melt the frost or ice which has accumulated, and if this works, you will be able to use the cooling system much sooner.
Improper Thermostat Setting
Surprisingly, having your thermostat on an improper setting can cause warm air to be blown from your air conditioning system. For example, if you have the blower fan set to ON rather than AUTO, that will cause it to run all the time rather than only during a cooling cycle. Between cooling cycles, the air you feel coming from the vents might be fairly warm. When you feel warm air coming out of your air conditioner, make sure the fan is set to AUTO and that you have the COOL setting selected.
Another reason why your air conditioning unit might be blowing warm air is that you have a refrigerant leak. When your system is losing refrigerant because of a leak, the air conditioner simply won’t have the appropriate charge to finish its normal cooling cycles. That means you’ll feel warmer air than you would normally. If this happens to be your problem, you should leave the repairs to a licensed HVAC technician who is experienced in handling refrigerants.