The invention relates to a fan-and-filter unit to be mounted in the wall of a switch cabinet or housing, and includes a fan unit inserted in a fan housing, a filter mat arrangement mounted upstream of the fan unit and a fan cover immobilizing the filter mat. An embodiment advantageous for operation of the fan-and-filter unit may be provided where the fan-and-filter unit has a filter mat monitoring unit which is designed to detect the service life and/or a degree of soiling of the filter mat arrangement and which includes an insert integrated into the fan housing or the fan cover and having an illuminated display visible from the exterior of the fan cover facing away from the fan unit and being designed to display at least exceeding of a predetermined or predeterminable service life and/or a predetermined or predeterminable degree of soiling.