Without the use of filter pads.
Water is the filter.
Because, in general, the basic principle of cold evaporation is widely acknowledged as the best method of air humidification compared with the two other methods of vaporization and nebulization . Because the cold evaporation system used by the Venta-Airwasher is the only evaporation system in the world which is based on a brilliantly simple technology without filter pads. As there are no filter pads, the Venta Water Treatment Additive can be added without causing any problem of clogging. Because the Venta system not only humidifies indoor air, but washes and purifies it as well. This is not possible with vaporizing or nebulizing appliances.