Need to ventilate
If lifting by hand, ventilate at least 3 - 4 times a day, for a minimum of 5 to 15 minutes. To save this work, there are automatic ventilation.
Mechanical automatic ventilation in skylights
Roof windows can already be fitted with automatic fans at the factory. These long-life fans ensure a constant air exchange according to the minimum air change rate prescribed in DIN 1946-6.
The mechanical ventilation is usually to be operated via the window handle. It can be completely closed, but normally this is not necessary. The ventilation is designed so that with the corresponding handle position an automatic continuous ventilation takes place.
In order to avoid too much heat loss at high wind loads, many roof windows have a wind load-dependent throttling. This throttling also works mechanically and automatically.
In order to prevent the ingress of water, the mechanical continuous ventilation is designed in such a way that water from outside (eg in case of rain) always flows around the fan and thus can not penetrate it. The continuous ventilation can thus be easily opened even in the rain.
This has the advantage that you can never forget or overlook to close the window in the rain, because it stays constantly.
Automatic ventilation in the case of electric roof windows
Roof windows with electrical control usually also have a built-in ventilation program. Here, the window is automatically ventilated at regular intervals and then closed again.
To prevent the ingress of water, the ventilation circuit is coupled to the rain sensor. If it triggers, the window is automatically closed within a planned ventilation period.
Ventilation with heat recovery
A very energy-efficient solution that can also be used with other types of windows, such as aluminum windows or plastic windows, is ventilation with heat recovery.
It is usually installed in the window frame or above the window frame and can also be retrofitted. Here is also an automatic continuous ventilation.
In this system, however, the heat of the exhaust air is transferred to the supply air, so that there are no heat losses through the continuous ventilation process. Such systems can transmit up to 85 percent of the room heat to the supply air, even if there are minus temperatures outside.