The Schellenberg Universal window fans provide a healthier room climate, despite closed windows or doors. They reduce the relative humidity and pollutants in the indoor air by means of constant air exchange. The continuous fine ventilation prevents the formation of mold on window sills and returns its original insulating properties to damp walls. The improved room air requires less energy to heat the rooms, which can also save you on heating and energy costs.The universal window fans are attached to the window wing of a plastic window with a few simple steps. To do this, a part of the rubber seal must be removed. The accessories required for mounting are included in the delivery. The universal window fans do not require a power connection and are operated purely mechanically. They are comparable in effect to more cost-intensive to or to exhaust systems.We recommend that you install a window fan on different sides of the facade for each 10 m² living area, in order to enable a transverse