Abstract: A hair dryer has a housing including an air inlet opening and an air exit opening for passage of an air stream. The housing accommodates a blower structure and a heater, and the air inlet opening has associated to it a filter element. Provided in the housing are a detector producing an output signal in dependence upon at least one temperature prevailing in the housing and having associated thereto a signaling device which is actuatable on attainment of a predeterminable threshold value of the output signal. The signaling device indicates to the user of the hair dryer that the filter element requires cleaning or replacement.