Abstract: Only a small useful quantity of washing water as close as possible to the spray nozzles of the windshield wiper system is heated. As a result of corresponding miniaturization, the heating time can be reduced to 5 to 10 seconds. A sufficient cleaning effect can be achieved in most cases by hot water after the windshield spray system is actuated two or three times. Additional cleaning can be carried out either by rinsing with colder or cold water or by repeating after 10 to 20 seconds. The water is heated via an instant heating element which, with a content of, for example, 10 to 50 cm.sup.3, can be installed even in a secondary chamber. Some of the heat energy is therefore stored in a larger thermal reserve tank of, for example, 1 dl.