Ventilation unit for a vehicle passenger compartment

The unit has a case (12) placed under roof of a passenger compartment, and including an air inlet and an air outlet. The case has a blower (28) including a motor and a radial turbine (26) permitting air circulation. The turbine is housed in an inner chamber (38) of the case. The blower is placed in upstream of a filter (40) and the chamber is directly delimited around the turbine.