Just like in the WC, we install a fan in the bathroom and we let it run for a few minutes after the person has left the room. After all, when we take a bath or a shower, the humidity rises. The result is that the mirrors steam up. In order to prevent this, we can fit a humidity sensor in the bathroom. When the humidity gets too high, the fan will automatically come on to get rid of the damp air. When the use of an analogue humidity sensor is not possible, then you can do the following. When the light is switched on in the bathroom, a timer can run for 5 to 10 minutes, for example. If the person continues to stay in the bathroom, the fan will come on after the set time. The chance that we are taking a bath or a shower is greater because we are in the bathroom for longer.