It depends on where you would use it, but always insulate completely from the outside, e.g. in the outside air before the [Kontrollierte-Wohnraumlüftung] with Armaflex because of condensation (which the rest of the piping should also have [Außenluft + Fortluft]), after the [Kontrollierte-Wohnraumlüftung] aluminum-coated mineral wool 30mm. There should also be a G4 pre-filter in the outside air (which is usually located in the [Kontrollierte-Wohnraumlüftung], but it won't help you because you don't want coarse dirt in the activated carbon filter). The manufacturer doesn't matter as well as the filters because they are made according to DIN.
