System of VMC set out again ensuring a continuous ventilation of housing without network of conduits centralized, thanks to two apparatuses (Mono and Multi) to combine according to housing. By a renewal of constant and controlled air, it allows the drainage of visible and invisible pollution, and in particular of moisture. Installed in livable volume, the apparatuses are characterized by a low acoustic level, low fuel consumption (microwatt, basic consumption of Mono to 2,5 W) and the possibility of rejecting the air in conduit, thanks to an electronic regulation of the flow.