What’s That Strange Noise Coming From My A/C?

If you operate your air conditioner regularly, then you probably know what it normally sounds like while turning on, shutting down, and even while running normally. Therefore, while you may not think about it all that much, it’s actually quite easy to recognize when your air conditioner is making a noise that isn’t normal. Bangs, clangs, grinding squeals, and other strange sounds are not something you should ignore: they’re your air conditioner telling you something’s gone wrong and needs to be fixed soon!

Here are a few of the most common atypical noises your system may be making and what your system could be indicating is wrong.


If you hear a thumping, thudding, or other type of banging noise, the most common cause is a loose or out-of-balance part throwing your system’s operation out of whack. Unfortunately, this isn’t usually something simple to repair: the most common causes include connecting rods, piston pins, or crankshafts in your air conditioner compressor. However, if you hear the sound from your indoor unit, the issue likely lies with your blower fan. The latter is certainly an easier fix, but you shouldn’t wait to have your issue diagnosed by a Sarasota air conditioning professional as soon as possible.


Squeaking, squealing, or loud screeching noises are usually a sign that something that moves is going bad. Usually you’ll hear this noise coming from your outdoor unit, as it’s a sign that your blower motor may be going bad (usually from too much exposure to the elements causing wear and rusting on your motor itself). This could also happen to your indoor blower motor as well. However, the motor itself may not be the issue all of the time, as your drive belt could simply need to be lubricated or replaced, which is a much simpler fix.


Have you ever heard a buzzing noise that sounds like an angry bee got stuck somewhere in your system? This is usually a symptom of vibration from somewhere, and could be an indicator of a number of different malfunctions. On the simple end, you could just have a loose part somewhere, debris stuck in an inopportune place, loose or out-of-balance fan blades, or refrigerant lines rubbing against something. Most of these issues aren’t super serious and require just a simple repair to get rid of the issue. However, buzzing could also be a sign that your blower is going bad, or even a refrigerant leak (which you could also identify by a lack of cold air coming from your system).


When your system turns on or off, a clicking sound is fairly normal and isn’t anything to worry about. What is a problem is if this clicking noise continues during normal operation as well. This could be a symptom of a defective controller or a failing thermostat causing an electrical problem that could damage your system if left unchecked for too long. If you hear a constant clicking, it’s a good idea to have a professional inspect your thermostat and control system to see if there are any issues that may need resolved. You may wind up having to replace your thermostat entirely.

Screeching, Screaming, or Loud Whistling

This is arguably the most serious noise on this list, as it points to a catastrophic problem that could not only lead to serious and permanent system damage, but possibly a danger to you and your family’s overall health. A high-pitched whistling or screaming noise during normal operation is usually indicative of a refrigerant leak. This is usually the result of your compressor not receiving a high enough flow of pressure, which is bad for it and could result in it overworking itself or overheating and failing. Not to mention most refrigerants can evaporate and turn into toxic fumes that are dangerous to humans and pets, particularly if your system is older and runs on R-32 Freon refrigerant.

If you fire up your system and hear a loud, high-pitch whistling from your outdoor unit, immediately shut off your system entirely and call a professional to conduct an inspection.

Need Air Conditioning Repair? Talk to your air conditioning repair experts at Airrific Air Conditioning & Heating today! Call (941) 371-3355.

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