Abstract: An air conditioning unit comprises a housing (1) which consists of a bottom (2), a roof (3), two side walls (4, 4'), a rear wall (5), and a front wall (6) having an opening (8) which is closeable by means of at least one door (7, 7') and which permits access to the interior of the housing; means for introducing supply air into the housing; and means for evacuating exhaust air therefrom. Two vertical air ducts (13, 13') provided adjacent to the front wall (6) have a large number of small holes (14) through which supply air can be introduced into the housing in the form of partial currents which are directed away from the front wall (6) towards the rear wall (5), both when the door (7, 7') is closed and when it is open.