Ventilation of a bathroom: an imperative how to envisage solutions?

A bathroom is a wet room since it contains several water points and is used for washing. However, the ambient humidity generated must be evacuated by good ventilation, otherwise it will settle on the surfaces, form condensation and develop traces of humidity and mould. Let’s discover together the possible solutions to properly ventilate your bathroom.

Why is it essential to ventilate a bathroom?

The bathroom is a wet room because of the many water points it has. It is important to ventilate it well to prevent the humidity released from settling there and forming mold through the phenomenon of condensation. By ventilating, you renew the ambient air, you evacuate bad smells, you preserve your walls, your equipment and your electrical installation from premature ageing, etc. In addition, ventilation helps preserve the health of the occupants of the house, since humidity can cause respiratory problems and skin or eye allergies.

Ideally, a bathroom should be ventilated with the window open for at least 15 minutes a day and the door kept open as much as possible during the day and at night to avoid storing humidity. However, not all accommodations have a bathroom with a window. Other solutions must therefore be found.

What are the possible solutions for ventilating a bathroom?

Recent homes and new constructions are systematically equipped with single or double flow VMC. The question therefore does not arise since the ventilation of the room is well done. On the other hand, there are solutions to remedy ventilation defects in older homes.

VMC (centralized mechanical ventilation)

It is quite possible to equip your bathroom with a VMC as part of a renovation. According to the regulations, the air extraction rate for a bathroom connected to a VMC extraction unit varies according to the number of rooms. It goes from 15 m3/h for one or two room accommodation at 30 m3/h beyond.

If you opt for this device, an extraction vent must be added to your bathroom.

There are two types of VMC: single flow VMC and double flow VMC.

  • La VMC simple flux ventilates the bathroom with a constant air flow (self-adjusting) or with a modulated start of air depending on the humidity level of the room (hygro-adjustable).
  • La VMC double flux uses the same operating principle as the simple flow CMV, but it also diffuses heated air.

Count 400 to 700 euros for a self-regulating single-flow CMV and 700 to 1,200 euros for a humidity-controlled single-flow CMV. For a double flow VMC model, plan 2,000 to 3,500 euros.

VMP (punctual mechanical ventilation)

If you do not have the possibility of installing a VMC, which remains the most effective solution, you can opt for a VMP. It is a smaller air extractor dedicated to humid rooms such as the bathroom. It kicks in when you walk into the room and shuts off a few minutes after you leave, once all the moisture has been wicked away.

A VMP must carry out between 10 and 15 complete renewals of the volume of the part each hour. All you have to do is connect it to an existing pipe or install an exhaust outlet. Note that if the VMC is discreet, the VMP is generally noisier.

There are two types of VMP: the single extraction VMP and the simultaneous extraction VMP.

  • The single extraction VMP contains only an air extractor and is installed at the entrance to the duct. It works alone the time of use of the bathroom.
  • The VMP with simultaneous extractions contains 3 connected extractors, which allows it to ventilate 3 different rooms. It works alone or by being connected to a switch for the light.

For a VMP with single extraction, count at least 75 euros, against a minimum of 110 euros for a VMP with simultaneous extractions.

The window

If your bathroom has a window, you can use it to ventilate your room. It can replace a VMC or a VMP if you cannot install one. The tilt-and-turn window, which opens slightly upwards, is recommended in order to ventilate your bathroom even when it rains. It is enough to ventilate well and to renew the ambient air in order to drive out the humidity. Do not hesitate to have this type of window installed in double or triple glazing.


If none of the previous solutions is possible for your bathroom, you still have the solution of aerators. They are extractors, but it is up to you to create the evacuation.

There are two models:

  • The window ventilator : if you cannot open your window, you can equip it with an aerator which is fixed on the glazing, inside and outside. You will need to cut the glass for this. There are manual, electric or battery-powered models, with manual or automatic control.
  • The wall aerator : more powerful, it consists of an aerator fixed in the bathroom, a conduit and an evacuation grille to conduct the humidity to the outside. So you have to drill the wall. This model is electric, but its control can be manual or automatic.

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