Young woman holds pillows over her ears to stop hearing strange air conditioner noises.

7 Air Conditioner Noises You Should Never Ignore

With summer around the corner, it’s almost time for you to turn on your AC for the season. But if it starts making strange sounds—like the ones below—it could spell trouble for your system. The pros at ComfortAire Heating Cooling explain what these air conditioner noises mean and what to do if you hear them. (Hint: Call us at 715-325-3969 in case of emergency.)

Clanking or Banging

Most commonly, clanking or banging is a sign that one of the parts inside your air conditioner is loose or broken. While it means you need one of our experts to help you replace or retighten fittings, these problems won’t typically ruin your system—unless you don’t have them fixed right away.

Hissing or Whistling

The key with these noises is to listen for how long they last. If your AC chirps for a few seconds but then stops, it could be as simple as gas in the unit’s expansion valve. Odd, but nothing to be alarmed about.

However, if it sounds like the system is whistling non-stop, the problem could be much more serious—like leaking refrigerant. Not only is this a pain, but if you have an older AC, it could be losing R22, a refrigerant that isn’t manufactured anymore. Your best bet with a hissing system is to turn it off and call in our pros for an expert diagnosis.


It’s normal for your air conditioner to hum as it runs—in fact, that tells you everything is working. But if that hum turns into more of a buzzing noise, it could mean a problem with a number of things inside, including the:

  • Fan motor
  • Condenser coil
  • Fan blades
  • Blower


A rattling air conditioner usually means one of two things: either parts are loose or deteriorating, or there’s debris like leaves and twigs gumming up the works. If this is the case, turn off your system and contact us to open it up and take a look inside.


With anything mechanical, grinding is never a good sound. As with other noises on this list, it’s likely caused by something loose inside—in this case, it’s usually a worn or damaged belt. However, it could also be an issue with the compressor.

No matter what, turn off your system and pick up the phone immediately.

Trust the Bryant® Factory Authorized Dealer—ComfortAire

With decades of experience in the industry, our expert techs have seen and fixed every problem out there. We’re always just one call away: either 715-325-3969 in Wisconsin Rapids or 715-342-0911 in Stevens Point. We’re ready and eager to fix any problems you might have.