A
breathing air humidifier (1) comprises a
breathing air inlet (3), a
breathing air outlet (5), and an
electric heating element (9). The breathing air humidifier (1) is switchable between a humidification mode and a preparation mode for preparing the breathing air humidifier (1) for operation in humidification mode and is designed to humidify breathing air supplied at the breathing air inlet (3) in humidification mode, whereby the breathing air is tempered by means of the
heating element (9), and to provide it in such a humidified state at the breathing air outlet (5).A method for operating the humidifier (1) comprises: when the humidifier (1) is switched on or off, switching the humidifier (1) into preparation mode and operating the humidifier (1) in preparation mode to allow the dissipation of
excess heat from inside the humidifier (1) due to prior operation of the humidifier (1) in humidification mode, with the
heating element (9) deactivated.