Filter unit

On A process for the sterilization of a filter unit (1) and a filter unit (1) for the purification of air with at least one filter layer (5, 7) is available provided that a safe and successful sterilization of the filter allows and can be manufactured at economical costs simultaneously.This is achieved, that a vaporous and / or liquid sterilizing agent in the filter unit (1) and / or in the at least one filter layer (5, 7) is introduced and that following the sterilizing agent by means of a gaseous Medium having a temperature above an activation temperature the sterilizing agent is activated, wherein the gaseous medium by means of a filter unit provided within the heater heated (4) becomes.