How to reduce the noise of your air conditioning? Installation tips, safe, noise barrier...

My air conditioner is whistling!
The noise of the motor and the fan keeps me awake!
The neighbors haven't stopped complaining about the noise pollution since the installation of my air conditioning...

Ah, if the air conditioning provides the undeniable comfort of a temperate temperature in winter as in summer, it is also often a source of noise which can cause many problems for you… as well as for your neighbour.

So, is silent air conditioning possible?

The good news is that there are plenty of solutions and anti-noise tips for air conditioners.

soundproof outdoor air conditioning

In this article we explain:

  • What makes noise in an air conditioner
  • The maximum noise limit allowed for an air conditioner or a heat pump
  • How to find a quiet air conditioner
  • Where to install the outdoor air conditioning unit to minimize noise pollution
  • Possible solutions to reduce the noise of an air conditioner (anti-vibration base, soundproofing screen or wall, soundproof box, etc.)
  • Tips for adjusting friction, hissing, liquid noises, etc., that come from the air conditioning

In short, everything you need to know to allow you to preserve the calm of your environment.

Why is my air conditioner making noise?

We must first understand that an air conditioner works like a refrigerator: it moves the "hot" outside to produce "cold" inside.

When the air conditioner is "split", it consists of:

  • one or more indoor appliances (monosplit or multisplit) including evaporators that cool the rooms of the house
  • an outdoor unit comprising the compressor, the fan and the condenser, and whose role is to reject outside the heat that it has extracted from the habitat

These two devices are connected by a circuit where the refrigerant circulates which allows the heat to be moved

The air conditioning noises you hear are mainly due to:

  • engine operation
  • to the mixing of the air

When the air conditioner is not "split" but "one-piece", all the elements likely to generate noise are therefore located inside a single machine, which is placed in the home. We understand that this type of air conditioning, which is certainly easy to install, is however much noisier. You “pay” for the coolness of your room at the price of a lot of decibels.

But beyond the normal operation of the device, other sources of noise can generate noise pollution at the level of the installation, such as:

  • Vibration noises caused by a play in the attachment of the device or its accessories
  • A lack of maintenance that causes the filters to be clogged or the fan to be clogged with dirt, leaves for example, and that this produces noise when it turns
  • Intensive use that causes the engine to overheat
  • The location of the outdoor air conditioning unit is also decisive because placed against a wall or in an interior courtyard it can produce a sound box effect.

Noise pollution: What does the law say about the maximum noise authorized by an air conditioner?

The Health Code sets the rules for noise pollution: no particular noise must, by its duration, repetition or intensity, affect the tranquility of the neighborhood or human health.

In terms of noise pollution linked to an air conditioning unit, the decree of August 31, 2006 on neighborhood noise applies (articles R.1334-33 and R.1337-7 of this code).

This decree does not specify an absolute limit of decibels, but it stipulates thresholds of noise pollution not to be exceeded in a relative way, so as to evaluate what the device brings as additional noise pollution compared to the usual ambient noise (noise of traffic, city noise, etc.).

Thus, the difference between ambient noise and residual noise (also called “emergence”) must not exceed 5 decibels during the day (from 7 a.m. to 10 p.m.) and 3 dB(A) at night (from 10 p.m. to 7 a.m.).

If exceeded, the offender is liable to a fine of €450 and may have the air conditioner or heat pump causing the noise confiscated.

Also good to know: in new constructions (building permit issued since January 1, 2000), homebuilders are subject to NRA 2000 regulations (see decrees of June 30, 1999 – Official Journal of July 17, 1999, p. 10658 and s. and p. 10660) which imposes absolute thresholds in terms of noise in dwellings, namely:

  • 58 decibels maximum between apartments for the transmission of impact noise (noise of
  • 35 dB in living rooms for noise generated by air conditioning

What sound level (dB) for an air conditioner and what are the quieter ones?

Air conditioning uses a motor, a fan, and needs to be placed in a ventilated space to cool down. It is therefore difficult to find perfectly silent air conditioning.

But depending on your air conditioning model, its price and its brand (Daikin, Mitsubishi, Atlantic, etc.), the level of noise pollution can vary significantly.

Be aware that a monobloc air conditioner emits on average 50 to 55 dB. It is the noisiest , especially since it makes noise in the room where you live.
The multi-split air conditioner emits a noise generally between 30 and 40 dB at the level of the indoor unit, and between 45 and 55dB (A) for the device located outside .
But 50dB is the noise of an old dishwasher, a noise that can already produce fatigue if it is suffered continuously.
So carefully compare the labels mentioning the sound power of the appliances before buying your air conditioner.

The latest models of air conditioning sometimes offer “silence” or “night” options that reduce noise during the hours when it is cooler and when everyone is looking for rest.

If you find your air conditioning too noisy, you can use smartphone applications that evaluate the volume in decibels. Although these estimates are not very precise, they can nevertheless give you an idea of its noise level and thus allow you to estimate the opportunity for a specific action.

Where should you install your air conditioning to reduce noise pollution?

ADEME (Agency for the environment and energy management) has published a comprehensive guide on best practices in terms of energy renovation, acoustic comfort and air quality in individual housing . There are illustrated recommendations on the best way to install your air conditioning or heat pump so as to minimize the annoyance that their operating noise could cause:

install outdoor noise canceling air conditioner

The windows insulate less from noise than the walls and can be opened: it is therefore necessary to keep the air conditioning as far away as possible from the windows (your own as well as those of your neighbours), in particular the windows of the bedrooms.

outdoor air conditioning tutorial without noise

We would naturally want to store our air conditioning unit in a corner between 2 walls so that we can see it less and because we forget that the noise will bounce off the wall … and actually increase the noise pollution!

If you want to make your outdoor air conditioner more discreet, don't try to hide it by sticking it against a wall in a corner. Instead, opt for an air conditioning cover that will make it disappear from your sight by covering it with a pretty wooden or aluminum casing that will act as a soundproof box for air conditioning noise.

ADEME has calculated that positioning your heat pump or air conditioning unit against a wall actually increases the noise pollution by 3 decibels , it even increases by 6 decibels if you place the device in a corner and by 9 decibels in an inner courtyard which will have a sounding board effect.

But sometimes, we don't have a choice of location for our air conditioning. Especially since the device must remain accessible for maintenance and not too far from the indoor air conditioner to which it is connected so as not to increase the bill.

In addition, it is also recommended to install the outdoor air conditioning units away from humidity, strong winds, the sun (avoid facing south or use an air conditioning cover to shelter the device ), and position them in a perfectly ventilated place.

Finally, try to install it if possible turned by 90° so as not to direct the noise of the right fan towards the windows of your neighbor opposite.

In short, if your outdoor air conditioning unit is hung on the facade near a window, placed on the balcony or in the garden of the house, it may be necessary to use additional solutions to soundproof your outdoor air conditioner .

An anti-vibration base to isolate the outdoor air conditioning unit

As we have seen, air conditioners generate vibrations during their operation. However, if the air conditioning is attached to a wall, these vibrations can be transmitted to the walls of the home and thereby accentuate the noise generated by the air conditioning. By isolating the device from the building, the propagation of vibrations and therefore noise pollution can be limited.

To neutralize this noise, you can place your outdoor air conditioner on Silent Bloc or even install an anti-vibration base .

anti-noise base vibration air conditioning

Anti-vibration pads are designed to prevent this transmission vibration by isolating the device . One can for example use a concrete inertia base which will be independent of the main building and raise it by placing it on anti-vibration pads . These bases can be found quite easily in DIY stores, but they must weigh at least three times the air conditioner to insulate it properly. Also, keep in mind that the device placed on this type of stud tends to move a little and this must therefore be taken into account when connecting.

Once the vibration noise has been neutralized by the base, it remains to prevent the propagation of the sound waves generated by the motor and the fan . It is therefore recommended to combine the anti-vibration base with the insulating properties of a formwork for the device under a suitable air conditioning cover.

An air conditioning box that acts as a soundproof box

Simple to set up, the formwork of the outdoor air conditioner is thus generally the most popular solution because if you install a quality box, it solves the visual nuisance in addition to reducing the noise pollution .

Would you like to make a casing for your outdoor air conditioner yourself? It is possible, but be careful because the task is not easy.
If you isolate the air conditioner completely, you will certainly not hear any noise, but your air conditioner will not be able to operate correctly. Indeed, it is always necessary to guarantee air circulation around the air conditioner because it is absolutely necessary for its operation.

The balance between sound insulation and openings necessary for ventilation is therefore difficult to find.

air conditioning noise canceling box

If you don't want to make any mistakes, prefer the installation of an insulating box specifically designed for outdoor air conditioners .
In collaboration with air conditioning specialists, Decoclim has thus launched a louvered air conditioning box specially designed to allow perfect ventilation of the outdoor air conditioner, while hiding the view of the device under a box which insulates the air conditioner soundlessly and attenuates a lot the noise .
The air conditioning cover, its material, its assembly and the specific orientation of its louvers, insulate the noises of the engine and the fan and thus make it possible to reduce the noise of the air conditioning by 10 to 30% . A really big gain when it comes to decibels .
This formwork also has the great advantage of being installed in less than 5 minutes and of being removed just as easily to allow maintenance of the device.

Sound insulation: Install a noise barrier

noisy outdoor air conditioning screen

Another way to reduce the noise pollution generated by an air conditioner is to install a noise barrier or wall. But here again, it is necessary to pay attention to the quality of the installation and to take account of the configuration of the premises.

The first thing to know is that not all materials have the same properties in the fight against noise . Must be distinguished :

  • Absorbent materials, such as expanded wood, plastic foams and glass or rock wool. They reduce the rebound of noise on the walls and avoid the resonance box effect.
  • Insulating materials, such as concrete or bricks. They prevent the transmission of noise through the air
  • Resilient materials, such as felt, cork, rubber. They prevent the propagation of vibrations

Ideally, a perfectly insulating wall should combine these 3 materials and offer a high density of material. In reality, the cost of such a wall is generally prohibitive...

Depending on the configuration of the premises (air conditioning glued to a wall or placed in an interior courtyard, etc.) and the type of main nuisance generated by the air conditioning (vibration or fan noise, etc.), screens or walls with different virtues are often used.
In addition, it must also be taken into account that the wall must be made of a material suitable for outdoor installation.

The second thing to keep in mind is the preferred location for the noise barrier relative to the location of the air conditioner.
If you are bothered by the noise of your neighbor's air conditioning, your first intention might be to install the noise barrier near your home. However, as seen in the diagram below, the insulating panel should actually be located closest to the noise source in order to protect the widest area.

noise reduction screen wall effectiveness

Tips and maintenance to reduce noise pollution

An air conditioner must be maintained regularly to prevent noise pollution from increasing. The filters can become clogged with an accumulation of dust, leaves can interfere with the operation of the ventilation... It is therefore advisable to carry out maintenance on your air conditioner every year.

If you have the impression that the noise of the air conditioner has increased lately it may be due to one of these causes:

Vibration noises:

Parts may have come loose and are causing vibration noises.
While the air conditioner is running, put your hands on the grille of the device: if the noise changes, tighten the screws on the frame of your air conditioner.
You can do the same with the different parts of the device to identify if certain parts have a "play" that generates a specific noise in order to neutralize it.

Hissing or scraping noise:

If your reversible air conditioning whistles or makes a grinding noise when you turn it on, this may be due to a defrosting problem. This is normally done automatically, but if you hear a hissing or rubbing noise, we advise you to start a manual defrost by leaving the appliance unplugged for several hours in order to melt any ice that may have accumulated on the 'evaporator. Like a freezer!
If despite this the noise persists once the device is reconnected, then it is advisable to call a professional to repair the device because a part must have been damaged at the level of the motor or the fan and it will have to be replaced.

Noise in the pipes:

As with a fridge, the refrigerant that circulates in the pipes, compresses, expands, and can generate noises (hissing, cracking, gurgling, etc.). These noises are normal, but if their intensity bothers you, contact a refrigerant specialist to fix the problem.

How to reduce the noise of a portable air conditioner?

There is no shortage of solutions to reduce the noise of the outdoor air conditioner. On the other hand, they are more limited to limit the noise pollution of a monobloc air conditioner installed inside the home.
It is therefore important to consider the criterion of decibels from the purchase even if it means increasing the bill a little.
Once the mobile air conditioner is at home, you can still act to a certain extent by installing the one-piece air conditioning unit on an anti-vibration base and regularly checking the tightness of its screws to prevent vibration noise that could arise. .