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Air conditioners: What do noise ratings mean and how do they affect home life?

If you have ever experienced staying in a hotel with a noisy old air conditioner rattling away through the night, you can be forgiven for thinking that if you have an air conditioner must be sacrificed for a cooler temperature. While this may be true of some older AC units, air conditioner noise is not a problem with most modern units.

What is noise?

The definition of noise is generally considered as “an unwanted, usually unpleasant, sound.” However, noise can be difficult to quantify as it is often subjective, perception varying between people and situations.

Take a moment to stop and listen. What can you hear? A ticking clock, the humming refrigerator? Perhaps the sound of a car passing by or a dog barking in the distance? Did those noises bother you before you started to focus on them? Many noises surround us every day, but unless we really concentrate on them, they generally go unnoticed, especially when they are continuous.

Sound is measured in decibels (dB). However, when referring to noise levels, measurements are usually given in dBA which is adjusted to account for the sensitivity of our hearing dependent on the sound frequency. Noise levels are on a scale from 0 dBA being the softest sound a person with normal hearing can detect, to 140 dBA, which is the level at which a noise could cause physical harm with just one exposure. Any prolonged exposure to noise levels above 85 dBA can cause damage to your hearing.

To put this into some sort of perspective, below are the noise levels of some common sounds we might hear. These are the expected levels from within 2 or 3 metres of the source.


Normal breathing10 dBA
Whispering20 dBA
Refrigerator32 - 47 dBA
Washing machine50 - 75 dBA
Dishwasher55 - 70 dBA
Normal conversation60 dBA
Vacuum cleaner60 - 85 dBA
Hairdryer60 - 95 dBA
Foor processor80 - 90 dBA
Pnemautic drill110 dBA

What are AC noise levels?

As with any piece of machinery, it must be expected that an air conditioner will make some noise. From fans to motors, the moving parts of an AC unit will create sounds as they work to do their job of cooling or heating your room.

The amount of noise generated by an air conditioner is related to its age, type and condition. It used to be the norm for air conditioners to operate quite loudly, but advances in technology mean that with today’s modern AC units, noise is no longer a problem.

The decibel rating for an AC should be given in the product specification of your unit. There will be one number for the noise of the air conditioner unit inside your home, and another for the AC unit outside. Air conditioner decibel levels can vary widely. The loudest part of an air conditioner is the compressor, which is the reason why portable ACs can be quite loud, getting as high as 55 dBA, since the compressor is part of the indoor unit. However, a modern split system residential air conditioner, housing the compressor in the outdoor unit, will be much quieter.

When it comes to noise levels, you also need to think about the outdoor unit of the air conditioner. Not only do you want to avoid any noise disrupting you and your family, you also need to consider your neighbours. However, when it comes to sound, particularly outdoors, there are other factors which can affect the level of noise you really hear. For this reason there are two ways in which sound ratings are evaluated. Sound power is the actual noise generated by the AC unit, while sound pressure takes into account a reduction in perceived noise as you move away. This is usually calculated between 1 and 5 metres from the unit. In reality, other ambient sounds from the surroundings will blend with the outdoor unit’s sound and also affect the level of sound you actually hear.

Whisper quiet air conditioning

Modern air conditioners are built with noise reduction in mind and advances in technology have brought noise levels far lower than ever before, so quiet air conditioning really is possible.

Daikin has invested in research and development to ensure minimising noise is a significant factor of their air conditioner design. Through the development of aerodynamic fan blades, specifically designed noise reducing air vents and the latest innovations in compressor technology, Daikin air conditioners have whisper quiet operation, with a cooling and heating noise level of just 19 dBA, the equivalent of a whisper. Daikin’s inverter technology also ensures that the unit never needs to run at high power to maintain a comfortable temperature, which keeps noise levels consistently low.

Read more about the Daikin range of air conditioners here.

How to reduce air conditioner noise

As they start to wear, air conditioners need to work harder so you often find an air conditioner can get louder with age, particularly those that do not have the advantage of modern technology. If you are having problems with a noisy AC unit, here are some things you can do to help keep air conditioner noise to a minimum.

  • Regular maintenance. By cleaning the filters, vents and heat exchangers you can avoid your air conditioner having to work harder which can result in more noise.
  • Check the surface it’s mounted on is stable. An uneven wall or floor can cause vibrations, so you may need to level the surface or use foam to absorb the shocks.
  • Reduce the fan speed. Higher speeds mean the AC will be louder as the motor and components work harder to cool your room. Turning it down to a more tolerable sound level usually allows the unit to cool the room, just a little more quietly.

When to call an air conditioner specialist

Over time you will get to know what is ‘normal’ when it comes to the noise level of your air conditioner and, like that humming refrigerator or ticking clock, you will get so used to it that you

barely notice it anymore.

Consequently, you should recognise any unusual sounds or increase in volume of your AC unit. If you notice any changes you need to contact your air conditioner technician as it could be a sign of a more serious problem.

  • Squeaking:  may need cleaning or lubricating.
  • Humming: could be a buildup of dust or a sign of something more serious.
  • Rattling: fan rotor may be loose.
  • Grinding: possibly a bearing problem or motor breakdown.
  • Hissing: the unit should be turned off immediately and checked for leaks by a professional

By getting into the habit of a good maintenance plan, regularly cleaning your air conditioner filters and getting it professionally serviced each year, you will keep your AC in top condition and achieve that quiet air conditioning you expect. 

Not sure where to start? 

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Alternatively, take a look at our Home Solutions Hub to find out everything you need to know about heating, heating with air conditioners and heat pumps.

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