Ventilus TQD 400+, 450 Q1 and 250 Compact heat recovery units

Photo: Mariusz Młynarczyk / CloudAir.tech

Three black Ventilus heat recovery units labelled TQD 400+, TQD 450 Q1 and TQD 250 Compact stand on metal frames before a backwall showing a cutaway house at night beneath the "Ventilus Rekuperatory" logo. Blue flexible ducts on a distribution plenum fill the foreground, and a wood-finish "Arkon" column with diffusers stands at the left.