Four Sounds You Don't Want To Hear From Your AC Unit

If working correctly, the only time you should ever hear your air conditioning unit is when it kicks on at the beginning of a cycle. If you hear noises while it's operating — or even while it's supposed to be off — you need to call an HVAC company to come investigate the cause. It could be a minor issue, or it could be the beginning of your unit failing entirely. Either way, the best way to avoid a major problem in the long run is to take care of any problems as soon as they appear.

Below are four sounds you definitely don't want to hear coming from your AC unit. If you hear them, schedule an air conditioning repair service as quickly as possible.


If you hear what can only be described as a pterodactyl in your ventilation system, the most likely cause is a broken fan blade that is scratching the metal nearby. It's extremely unpleasant to listen to, but even worse, it can damage the inside of your unit and cause a major air conditioning system repair. Get it fixed as you can to preserve the integrity of your system and your own sanity.


A loud squealing sound could also be related to your main air conditioning unit, but instead of the fan blade, it could be the belt that's attached to the motor. The fan belt ensures that your blower is operational to begin with, so if it snaps, you can expect the entire system to stop working overnight, prompting a major air conditioning repair. If that happens, you'll be left without cold air indefinitely.


While the other two on this list are signs of a major issue, a clanking sound in your air vents could be relatively minor. A bolt may have fallen off one of the attachments and is rattling around inside your air vents, which would need to be found and reattached to ensure the connection. Alternatively, it could be a major problem — it could be a piece of the unit itself that has broken off and making the sound instead.


When you turn your air conditioner on initially, you should hear a faint click in your system. If you continue to hear clicks after it's on, even irregularly, you may have a problem with the electrical relay that is causing your unit to shift on and off repeatedly. Left unattended, it could short out your system entirely, so schedule an air conditioning repair service to have it looked at.