The Helios KWL-EVH 220 D is a built-in preheater element specially designed for the KWL EC 220D ECO ventilation unit. Providing a heating capacity of 1.0 kW, this electrical preheater ensures reliable intake air warming during very low outdoor temperatures, preventing heat exchanger icing and maintaining efficient ventilation performance. Ideal for use in passive house systems, it supports optimal climate control and energy efficiency