1. Heating and/or air-conditioning installation, especially for a passenger compartment of a motor vehicle.2.1 In known installations for heating and/or cooling, hinged flaps are employed as control means for distributing the air, which flaps need a large mounting space.2.2 It is proposed that a mounting frame with hinged or sliding lamellae be inserted into the free cross-sections of each of the channels to be controlled.2.3 Use of the motor vehicle air-conditioning systems.