Abstract: An electrically heated vaporizer having a pair of prongs to be plugged into a wall socket for vaporizing a chemically treated diffusable tablet for deodorizing, disinfecting, perfuming or otherwise treating air of a room, is formed of a hollow dome-like casing suitably foraminous so that air currents induced by a heater pass about the tablet to effect diffusion thereof. The casing is separated into two compartments by a shelf in the form of a row of laterally spaced pins or tines. On the under side of such shelf is an electrical heater for inducing the air currents, air inlet ports being on one side of the shelf and air outlet ports on the other side. The electrical heater is carried by a back plate which has hook-like catches adapted to snap into edges of the air ports for securely holding the parts in assembled relation. Cooperative locators insure proper positioning of the back plate and casing.