The bathroom, toilet and livingroom/kitchen are connected to a mechanical ventilation system. The valves on the exhaust openings are set to the desired exhaust capacity and should therefore not be adjusted or closed. Any interruption of this permanent ventilation (by switching it off) will irrevocably result in serious damp problems, such as mildew on the walls and ceilings and condensation on the windows. Clean the vents regularly with a soft soap solution. In addition, ensure there is a supply of fresh air by regularly opening windows or doors.
There is no mechanical ventilation in the rooms. For good health, it is important to ventilate your room properly. You can do this by using the ventilation grids above your window or by opening windows. More information can be found on the website of Milieu Centraal.