Close-up of a woman making the sign of silence with her fingers

How do I stop a noisy ventilation system?

CMV (controlled mechanical ventilation) is a system for circulating air inside a house, building or structure. It allows, among other things, to maintain a healthy habitat with a constantly renewed atmosphere, free of humidity and pollutants.

Normally silent, the CMV can however in some cases make unpleasant sounds in everyday life. Let's find out why a noisy ventilation system can be a problem and how to solve it.

Why does the CMV make noise?

Woman bothered by noise in the house

While ventilation inside the house is usually done as quietly as possible, a noisy ventilation system can be a real nuisance to your nerves in the long run. Buzzing, rattling, repetitive sound, it is not possible to put up with this on a daily basis, especially since the use of a VMC is indispensable in a house.

To understand why the CMV makes noise, you must first understand how it works. A controlled mechanical ventilation rotates by circulating air inside a building. This circulation is achieved by means of an electric motor that drives a fan. The fan blows air into the house by means of an artificial air flow.

The airflow created by your CMV normally makes a low or even inaudible sound, but with wear and tear, noise can occur. This can depend on several factors:

  • a problem in your installation (if the system is new);
  • no maintenance has been carried out for a long time on your entire installation;
  • a hardware failure (a damaged fan or an electrical problem).

What should I do if I have a noisy ventilation system?

PM Bricolage | How can I reduce the noise of the VMC?

The first thing to do when you are bothered by the noise of your VMC is to clean it. Some periods are better than others to do this, but if you are in a hurry, don't wait. Usually, a ventilation system is cleaned after the winter, as it is supposed to have been heavily used during this period.

The purpose of cleaning is to remove the accumulation of dust, especially from the air vents. To clean them effectively, it is recommended that you dismantle them, suck out as much dirt as possible from the grille and ductwork, and possibly rinse your vents. Allow them to dry thoroughly before reattaching them and, as a precaution, switch off the power supply before you do so. To keep the advantages of a double flow CMVDon't forget to clean the air vents.

After this procedure, the noise is normally gone and that is very good news. If not, you have not wasted your time, because the air circulating in your house will always be healthier than before the maintenance. In any case, you will have to make further checks to find out the origin of the unpleasant sound if it persists:

  • If the noise nuisance is not caused by a maintenance problem, and your ventilation system is not new, the problem is most likely to be the motor. Over time, it is normal that the motor wears out and does not work as well as it did in the early days. It can also become clogged and require more effort and therefore make noise. Beware: in this situation the motor can heat up and cause a fire, so it is strongly advised to change it.
  • Alternatively, the problem may lie with the ventilation ducts. The erosion of time can cause them to become torn or clogged. In this case, it is strongly recommended to call in a professional, as it is difficult to do this yourself.
  • Finally, if your installation is new and making noise, it is clearly a question of calibration or a design fault. Quickly go back to the person who did the installation, or see them again if you did it yourself.

How can I reduce or insulate the noise from a noisy ventilation system?

Craftsman connecting a flexible duct to a single flow controlled mechanical ventilation

If your ventilation system is too noisy and is working perfectly, there are solutions to reduce the number of decibels in your system. You can use :

  • Silent blocks: these are pads to be placed on the engine to reduce the vibrations caused by its mechanism when it is placed on the ground. Polystyrene can also be used instead;
  • a soundproof box: if you want to go further, you can put your motor in it. This can be bought or made by yourself;
  • Acoustic rings: these are foam collars that are placed around the CMV ventsThese will reduce the noise of the circulating air.

These solutions are not always reliable, but they do provide a little more comfort, as they reduce the disturbance caused by your installation.