As the refrigerators and freezers fit behind the unit door, they integrate into a fitted kitchen creating a uniform look. The appliance door and unit door are fastened to each other by the door-on-door system. Ventilation is effected via the plinth of the appliance, meaning that no louvres have to be provided in the worktop. The Vario plinth allows adaptation in height and depth to the kitchen units. Ventilation is effected by way of the plinth and therefore no ventilation slots are required in the worktop. The Vario plinth permits adjustment in height and depth to the kitchen units.