An electrical device for evaporating a volatile liquid (for example an air freshener) into a room employs a wick (14) which extends upwardly from a container of the volatile liquid. A ring heater (16) is in the vicinity of the end of the wick and assists the evaporation. Vapor escapes from the device through an aperture (10) in a casing above the wick. The vapor emission rate is controlled by a user, who operates a control member in the casing, to alter the vertical position of a tubular body (18). Vapor may flow from the wick to the exterior through the tubular body (18) and then through the aperture (10). However, in all positions of the tubular body vapor may also flow to the aperture, and thence to the exterior, by an auxiliary route, not through the tubular body. It is found that the provision of this auxiliary route for vapor significantly improves the performance of the device. The tubular body (18) may have an upper surface (31) comprising a wall (32) and apertures (33). The wall (32) together with the apertures (33) ensures that any non-evaporated volatile liquid is directed back towards the heater. |