Why Is Your AC Making Noises And Is It Normal?

Is your air conditioner making weird noises and is that considered normal? Well, some you shouldn’t worry about while others could be a sign of an underlying issue with your air conditioner.

Read on to learn how to tell if something’s wrong with your AC and what you can do to fix it.

What A Normal AC Typically Sounds Like

Low Level Hum

Most ACs will make a low humming noise that’s quiet enough to disappear into the background. In these cases, you have nothing to worry about. This is just the noise coming from the fan running and blowing air out into your home from the ducts and vents. 

That said, different units may produce different levels of noise.  

Read The Manual For Individual Units 

Generally, newer models of air conditioners tend to be quieter thanks to enhancements made to the technology over time.

The manual that comes with your air conditioning unit should contain information on how much noise your system will be making. This noise is measured in decibels (dB) and there will normally be 2 measurements:

  • Noise of the unit measured inside the home
  • Noise of the unit measure outside the home

Interior Sounds

The interior noise level depends on the type of air conditioning system but generally split systems shouldn’t go louder than 35dB while ducted systems can go as low as 23dB.

Here are some comparisons to get an idea of where these measurements rank with everyday noises:

  • 20dB is comparable to a whisper
  • 40dB is comparable to ambient noise in a car park
  • 60dB is comparable to a conversation
  • 70dB – 80dB is comparable to a vacuum cleaner

Exterior Sounds

Once again, the exterior sounds emitted by your air conditioner would depend on the type of system, model and brand. But typically the noise level should not go higher than 5dB above the ambient noise level in your outdoor area


Interior Sounds

23dB – 35dB

Exterior Sounds

< 5dB

Note: For comparison, a quiet room in a house can emit sounds between 20dB to 30dB

Other Sounds To Watch Out For

Loud Humming

Low humming is acceptable but if it gets louder than usual, it could mean that there’s an issue with the fan motor. 

The fan motor might be blocked from dust particles, dirt or debris, which can be what’s causing the loud humming sounds. If this is the case, you’ll need to get a trained professional to fix the issue as unblocking the fan would require access to the internal parts.  


Rattling noises are probably one the most common type of sounds you might hear from an AC. The noise might be coming from a buildup of debris within the system or if parts have been damaged and broken loose and have started to rattle around the ducts or fan inside the aircond. 

Rattling sounds could also mean that a fan blade may have been damaged or bent. If you encounter this noise, it’s best to get a trained technician to look at it immediately as the problem could get worse if not dealt with quickly.  


A buzzing noise could be the sign of an electrical problem within the system. This could be an indication of damaged or loose wiring, which can be dangerous and could be a potential fire hazard

If you suspect that there is an electrical fault within your air conditioner, seek help from a professional immediately before it worsens into a more serious issue. 


If hissing noises are coming from your air conditioner, it might be because of an air leak somewhere in the system or worse – a refrigerant leak. Air leaks are manageable but refrigerant leaks can be dangerous as the gas contains hazardous chemicals. 

If one inhales the refrigerant gas, it can be poisonous and cause serious harm. If you suspect that there is a leak within the system, get a trained technician to check it out for you right away. 

How To Prevent Unwanted Sounds

Professional Servicing

This is the best advice to offer to anyone using air conditioners as it can resolve most of your air conditioning problems. Making sure to have routine servicing of your split system will avoid unnecessary (and sometimes dangerous) problems.

In general, get your air conditioner serviced at least once a year, or twice if you’re using it for both heating and cooling. 

A technician would be able to clean your system thoroughly and check if all parts are working as they should. If some parts are faulty, the technician can replace them before they become a hazard. 


Regular cleaning around your air conditioner will ensure that dust and debris don’t build up around your system and lead to other problems. 

Also, make sure to also clean your air filters once every 3-4 months to make sure that airflow from your AC is not restricted. 

Replace With A Newer Model 

If your AC is still making loud noises but does not have a serious issue other than it being an old model, it might be time to consider upgrading to a newer unit. 

Newer models have evolved to contain better technology, with more advanced features and have quiet operation. Some of these models even have lower running costs and more versatility compared to their older versions. 

Consider Where You Place Your Indoor & Outdoor Unit

Where you place your indoor and outdoor units will affect the noise level the system generates. If you’re unsure of where to place them, rely on your air conditioning technician to point you in the right direction. 

They’ll be able to give you advice on placing your outdoor units as far away as possible from your neighbours windows or bedrooms for instance. They can also provide other options to keep the noise level low

Don’t Settle For A Noisy AC

You don’t and shouldn’t have to put up with a noisy air conditioner. Unless it’s a sign of an underlying issue, noisy air conditioners are a thing of the past. 

Keep an ear out for the noise your system is generating and try out the solutions that we’ve suggested. If your air conditioner is due for a service, book an appointment with our Gaschill experts today and get your system up and running again.