Abstract: A heating-ventilation and/or air conditioning apparatus for use in the passenger space of a motor vehicle. The components of the apparatus, disposed on the side of the passenger space in relation to a transverse partition separating this passenger space from the front engine compartment, comprise a heating device for producing warm air and having a heating impeller for sending this warm air into the passenger space and a ventilation device for producing the cool or conditioned air and having a ventilation impeller for sending this cool or conditioned air into the passenger space. The apparatus is applicable to motor vehicles having a very inclined windshield, especially for "single box" type vehicles.