The invention relates to an assembly including a heat exchanger and a mounting on which the heat exchanger is mounted. The heat exchanger including a first channel for circulating a coolant supplied by a first collector provided with a first pipe in which the coolant can circulate. The heat exchanger also including a second channel for circulating the coolant supplied by a second collector provided with a second pipe in which the coolant can circulate. The first and second channels define a heat-exchange surface that extends in a substantially vertical plane. The first pipe is located in a lower half of the first collector along a first axis parallel to the plane of the heat-exchange surface, with the second pipe located above the first pipe along the first axis. The invention further relates to an air-conditioning loop including the above-described assembly.