The compressor is usually the component responsible for air conditioner noises, but an issue with this part or another component connected to it can cause a buzzing noise.
While it is normal for air conditioners to make a bit of noise when they are running, a strange buzzing sound could indicate an internal issue.
If you notice that your air conditioner is buzzing, the best thing to do is to inspect your coils, the inside of the casing and the compressor.
Normal air conditioner noises
If you have been an air conditioner owner for a long time, then you will know that these machines do tend to make some noise as they work.
However, these normal air conditioner sounds should never get louder than a low hum if all of the components in the air conditioner are functioning correctly.
Air conditioner making a buzzing noise
If you have found that the noise coming from your air conditioner has suddenly changed from this low hum to a more noticeable buzzing or the buzzing seems to get louder every time that the air conditioner starts a new cycle, this is likely a sign that there is some kind of underlying issue in the system.
There are a few different main components in your air conditioner which are responsible for making most of the sounds that you hear on a regular basis, like the compressor, condenser and even the fan motor.
If your air conditioner is buzzing, the chances are high that one of these components is to blame. But it is not always as simple as the component itself having an issue.
Air conditioners are complex systems, and many of the components have to work in tandem with others to complete every air conditioning cycle.
This is why, even if your compressor is the component making the buzzing sound, the actual root cause of the problem may lie in frozen evaporator coils or loose parts and debris inside of the casing.
When something is preventing proper airflow or one of the unit’s components is not working as it should, this could force one of these main components to work even harder than it usually does, which is what ultimately leads to the buzzing sound that you are hearing.
This also means that the best way to diagnose, and hopefully stop the buzzing sound coming from your air conditioner, is usually to open the air conditioner up. This way, you can have a look around for the root cause of the problem.
Are your coils frozen?
Frozen coils may be preventing your air conditioner from taking in enough air and your compressor may be overcompensating to make up for this deficit, which could be causing the buzzing noise.
If you notice any ice, pools of water or warm air coming from your air conditioner, you may be dealing with frozen coils. In this case, your best course of action will be to switch off the unit and let it thaw completely.
Then, switch the unit back on and run it in the “Fan Only” mode for about an hour.
Do you notice any loose parts or debris?
Rattling and buzzing noises in an air conditioner can sometimes come from loose parts vibrating inside of the casing.
These parts can prevent proper airflow, but they may also damage other components or even be a fire hazard, thus, it is important to get them repaired.
Other loose pieces of debris, like sticks leaves or dirt, which may have built up on the inside of the air conditioner casing, could also obstruct your fan blades.
So it is a good idea to scoop these out if you find them.
Possible issues with the compressor
If you notice that your air conditioner is only making the buzzing noise as it starts up or starts to cool or that this process intensifies the buzzing noise, then the issue may be more closely related to your compressor.
The compressor is one of the most important components in the air conditioner, and if you notice that the compressor seems broken or has any loose wires, it might be time to hire professional help to repair it.
However, the buzzing sound may also be caused by less serious issues related to the compressor.
Sometimes the compressor’s rubber isolation pads can wear out, which will make the compressor noisier.
The buzzing could also be coming from the outdoor contactor switch if it is not properly connected.