Common Causes of Bad Odours Coming From Air Conditioners

air conditioner

Nobody wants to turn on their air conditioner expecting refreshment, only to find a bad oudour coming into their environment. 

If unpleasant scents start circulating from your unit, it’s most likely time to get an aircon service to deal with the situation. It’s a good idea to identify what’s causing the smell so that you know what you’re dealing with.

Here are some of the most common reasons your aircon smells bad:

Overheating or Mechanical Faults

If your air conditioner smells like burned wires or melting plastic, it’s best to turn it off and contact your air con specialist. 

Your system might also be suffering from overheating due to a faulty motor or damage to certain internal components. An aircon repair service should be able to fix the issue, so call them to check your unit.

You should also reach out to an electrician if your wiring is compromised. If you still smell a burning odour when you shut off your AC, call the fire department right away and turn off the breaker.

Sewage Leaks

If you smell a rotten sewage-like odour coming from your AC, you might be dealing with a sewage leak. This means you have a problem with the drainage pipes, which need to be checked immediately.

Because the AC circulates air, any problems with your P-Traps and sewer lines can result in a smell that emanates and spreads throughout your home. You would need to get a plumber to check on this to ensure that you are not dealing with severe damage.

Mould and Mildew

Not only is mould a disgusting sight, but it also smells especially bad. It’s a result of excess moisture being trapped in the air. If you smell a musty odour coming from your air conditioner, you may be dealing with mildew or mould growth.

This can be dangerous to your health, so it’s best to get it managed right away. You can prevent this by getting your air conditioning serviced annually to maintain proper humidity and moisture. You don’t want too much moisture, but you also don’t want things to be dry, so a tune-up should do the trick.

Clogs in the System

If your air conditioner smells like a wet dog, then it’s possible that you have a build-up of condensed water that is not draining properly. It’s best to get it checked to check for any clogs, clear them, and optimise the setup to prevent further clogs.

Dead Pests

Rotting smells can mean a pest may be trapped in your air conditioner and has died in there. In this case, you need to get rid of the carcass right away. An aircon service can get everything sanitised and identify any bugs or pests being harbored in the unit.


If your AC has a persistent odour coming from it, have it checked to fix the situation.

Roberts Air Conditioning specialises in the installation, repair, and maintenance of air conditioning units. Contact us to get quality air conditioning service in St. Mary’s and surrounding suburbs.