Compact heating, ventilation and/or air-conditioning system

The appliance has an air inlet casing (2) comprising an air inlet pipe (18) allowing entry of air flow in the appliance. An air distribution pipe (30a) allows distribution of the air flowing out of the appliance. The air distribution pipe is integrated into the air intake casing. The air distribution pipe is delimited by an external wall (38) that comprises a localized deformation part (44) partially accommodated in the air inlet casing. The localized deformation part is defined by a reversed section (42) of the external wall.