Electric heating device, in particular additional motor vehicle heating and motor vehicle air conditioning device

The device has a heating block comprising a radiator element that lies on a positive-temperature coefficient (PTC)-heating element. The radiator element is held in an air passage surface (8) with a housing, which is held in a sliding holder. A flow-resistance element (10) is molded such that a clear distance between outer dimensions of the housing and inner walls of flow channels bridges the height of the device, which is inserted into an insertion opening in the flow channels. The sliding holder comprises retaining straps (14) that lie opposite to each other. An independent claim is also included for a motor vehicle-air conditioning device with an air conditioning housing.