In supply and exhaust air systems with cross-counterflow WT, the air is usually exchanged room-by-room without supplying other (overflow) rooms. A variant to wall-integrated systems is the integration of the ventilation unit in the area of the window, e.g. in the roller shutter box. This means that no visible air outlets are necessary to disturb the façade appearance, so that the device can be placed without any loss of design.
Source: bauwion
