Air conditioning system comprising a support carrying constituting elements of the system

The system (1) has an air-conditioning, heating and/or ventilation installation unit (3) that is constituted by a plastic material case (7). Coolant/heat transfer fluid heat exchangers (13, 14), an internal heat exchanger (19), a distribution block (22), a hybrid or electrical compressor (15) and an accumulator (16) are connected on a support (100). The support is provided with a fixation unit (103) at a chassis of a motor vehicle, and a gripping unit (102).