Abstract: A housing for a heating or air conditioning unit for a motor vehicle is provided, which housing is disposed under the windshield at the middle of the vehicle and includes portions extending adjacent the lower or passenger foot region. This housing is provided with air outlet nozzles for directing warm (or cooled) air into the passenger foot region. The housing includes two upper housing parts separated by a separation plane extending perpendicular to the vehicle travel direction and a lower foot level housing part for the air outlets at the foot level. These three separate housing parts are form fittingly assembled together by slidably interengageable housing parts. With this arrangement, the foot level housing part can be assembled with the other housing parts without the need of additional work tools and is so integrated into the complete housing assembly that, with the slidable connection of the housing parts together, the foot level housing part is also securely and rigidly assembled.