Different AC Noises & Their Causes

In today’s world, our ACs are, now more than ever, an integral part of our daily lives. It would be near impossible for us to function without them, especially in the hot climates of St. George and Mesquite. As important as our air conditioners are, most homeowners have very little operational knowledge of the units and wouldn’t be able to fix them.

From time to time, your air conditioning unit may make various sounds. If you can tell the difference between the sound the AC makes when it’s doing its job and when it means there’s a problem, you’ll save yourself the hassle of calling in the experts when there’s nothing wrong. Here is a list of sounds you might hear emanating from your air conditioning unit and what each sound could mean.

Clanking or Banging

If the unit makes a loud clanking sound, it might be because the compressor unit, indoor blower, or outdoor fan has come loose and needs to be replaced and tightened. Connecting rods and piston pins are some of the most common culprits. These two parts bear a lot of the pressure of cooling. If they need to be tightened, the unit will not be working at full capacity.

A banging sound might indicate that something smaller within the air conditioner has come loose, like a nut or a bolt that needs to be looked at.

Buzzing Noise

Buzzing noises come from several conditions. Buzzing could mean that coolant is leaking out of your AC unit. If the buzzing sound is accompanied by a lack of cooling, this could be the culprit.

Another reason could be that your condenser coils need cleaning. Not only do dirty coils create a low buzzing sound in the unit, but they also make the whole cooling process inefficient.

If there are loose metal plates inside the unit, they can cause electrical charges to pass between them, causing a buzzing sound. Any one of these can be the source of the sound, but it’s hard to make a diagnosis without more information. This is best left to the professionals.

High-Pitched Squealing

The culprit for this sound is usually built-up pressure within the unit, most likely caused by a compressor that needs replacement.

Hums and Clicks

Humming usually means something is stuck inside and needs to be removed. On its own, the humming sound isn’t likely to cause any permanent damage to your unit. If the humming is accompanied by a clicking sound, however, that could mean that the thermostat is acting up. In that case, you would need to get your AC looked at quickly.


Rattling noises are usually just indicators of old age, but they can also mean that there is in the unit that shouldn’t be there. Twigs, leaves, pieces of plastic, and foreign objects can somehow find themselves where they shouldn’t be. Once you remove these pieces of debris, your AC should stop ratting.

If your AC makes a sound you can’t identify, it’s time to call in the experts. A-1 Services can take of everything and anything related to your air conditioner. If your AC starts making any of these sounds, contact us to get the problem solved.