AC unit with tool bag and tools

If you have a noisy air conditioner and are getting complaints from your neighbours, your AC unit is likely not working properly. Sure, your AC unit will always make some noise, but it shouldn’t cause a disturbance. 

By the way, don’t dismiss complaints from your neighbours if you can’t hear the noise. Outside AC units might be closer to your neighbour’s window than to yours. If so, you need to address this problem before your neighbour makes a noise complaint and before the AC unit’s issue gets worse. Here are some common causes of unusual noise from your air conditioner. 

Causes of a Noisy AC Unit

Depending on the type of noise your AC unit is making, you can narrow down potential causes. Here are the top noises we encounter:   


Clicking can be a normal noise or the sign of a very serious electrical problem within the AC unit. While the AC unit should click when it turns on and off, if it is constantly turning on or off it has a problem. The clicking is caused by the electrical components, so one or more of them is likely the trouble. However, this clicking may also be caused by a broken thermostat that keeps signaling the AC unit to turn on or off.   

Buzzing or Humming 

A humming or buzzing noise is often caused by vibration. This typically means that a part is loose and potentially knocking into another part of the AC unit, damaging both. Any part of your air conditioner might be loose, from the fan to the compressor. Or, the buzzing could be caused by an electrical problem such as arching. Either way, these problems can get worse if not attended to.  

High-Pitched Noises Such as Squealing 

Squealing, screaming and whistling are all serious signs that your air conditioner could be a safety issue. For example, screaming often means there is a refrigerant leak or a problem with the internal pressure of the unit. You should immediately turn off the unit if it is making a high pitched noise. 

AC unit on side of house

When to Call the Experts 

Essentially any time that your AC unit is making an unusual noise it is wise to call up your HVAC professional. Unless you work with AC units, you will likely be unable to diagnose the problem and fix it. The longer you leave your AC unit running when it has a problem, the more likely it is to get worse, or completely breakdown. So, we recommend you call your HVAC technician right away.   

We can help with your noisy AC unit. For all of your AC and HVAC needs contact the experts at Woodbridge GTA ClimateCare. 


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