Noisy AC

It’s July. It’s hot. You need to cool down, fast.

So, like many people in Guelph, Kitchener, Waterloo, and Cambridge, you turn on your air conditioner, only to discover that it sounds, well, awful.

In particular, there are a few noises you want to watch out for:

  • Hissing.
  • Banging.
  • Clicking.

Read on to learn what’s causing each of these awful sounds.

Then, contact us at Guelph ClimateCare for prompt air conditioner repair.

1. Hissing

Your air conditioner should not sound like an angry snake while it’s in operation.

If it does, it could signify it needs maintenance to fix the following:


  • More than likely, refrigerant is escaping from a line due to something like a tear or rip. When this happens, your AC will lose its capacity to cool.
  • Don’t wait to get this looked at. If too much refrigerant is lost, the compressor may be damaged beyond repair. Without a compressor, your air conditioner can’t function.
  • With a line leak, you’re actually paying to use a home cooling system which isn’t keeping your home cool.
  • In order to repair this properly, the leak must be sealed first and then any lost refrigerant needs to be replaced.


  • If the hissing noise is coming from your thermostat, that’s symptomatic of an electrical problem (such as a short circuit or disconnected wire).
  • Do not attempt to repair this yourself. Live, uncontrolled electricity flowing to the thermostat can give you an unpleasant shock.

Whenever your air conditioner turns on, do you sometimes think to yourself “that sounds like gas or steam escaping?”

If so, follow your instinct and contact us to schedule repairs.

2. Banging

Blower wheel

Whether it’s from your furnace or your air conditioner, be wary if you hear any banging sounds.

Banging coming from inside your AC sometimes means there’s a loose or unbalanced part rattling around inside there.

Although it could be anything, more often than not it’s caused by things like:

  • Connecting rod.
  • Piston pin.
  • Crankshaft.
  • Blower unit.

An incessant banging sound could also mean the compressor has reached the end of its life and needs replacing.

If the banging noise is accompanied by the following, you’ll want to get the compressor looked at ASAP:

  • The AC motor won’t start.
  • The air conditioner keeps turning on and off, over-and-over again.
  • It feels like it’s overheating.

3. Clicking

Of all the sounds listed in this blog, clicking sounds are perhaps the easiest to identify and diagnose, especially if you can determine when and how often it clicks.


  • If the clicking noise starts slow and gets louder and faster, there could be something like a wayward branch or loose part hitting the fan blades.


  • It’s normal for your AC to make one click at start-up; this is the thermostat telling the capacitors to get to work.
  • It’s an electrical problem if the clicking noise is constant, but the air conditioner won’t turn on. Don’t try to fix this yourself.
  • The thermostat is sending the signal, but the capacitors aren’t receiving it due to shorted wires or a fault control board relay switch.


  • If the clicking noise sounds like it’s coming from outside, that could mean there’s an issue with the compressor.
  • Sometimes, it could be as innocuous as a loose bolt or refrigerant tubing. The best way to know for sure is to have an expert look at it for you.

Hear any of these three sounds? Call us ASAP

This summer, there are two things you don’t want to happen to your air conditioner:

  • For it to fail on the hottest, stickiest day of the year.
  • For you to spend a fortune on unwanted AC repair.

Should your air conditioner make any of the noises listed in this blog – or any other worrying sounds – don’t try to fix it yourself or hope it “goes away on its own.”

Contact the AC experts at Guelph ClimateCare.

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