An electrical motor-vehicle auxiliary heating device is held in a housing forming oppositely situated air passage areas with formed air passage apertures. A flow resistance element protrudes beyond the outer side of the housing, is manufactured as a component independent of the housing, and is connected to it. The invention also relates to a motor-vehicle air conditioning device with an air conditioning housing which accommodates a motor-vehicle auxiliary heating system and which forms at least one flow channel, which leads to the motor-vehicle auxiliary heating and forms an insertion opening for the motor-vehicle auxiliary heating as well as a boundary wall situated opposite the insertion opening. At least one flow resistance element is provided that is manufactured as a component independent of the housing and the air conditioning housing and that bridges a clearance distance between the housing and the wall(s) of the air conditioning housing.