Abstract: The invention relates to a device (1) for heating a fluid (9), with a housing (2) comprising a housing shell (3), a housing base (4) and a housing cover (5), with at least one inlet opening (11) and at least one outlet opening (13) for the fluid (9), and at least two electrodes are disposed in the housing (2) at a distance (25) apart from one another, which are each electrically conductively connected to a pole of at least one pulse generator (20). At least one other electrode (45 or 46) is provided or at least two other electrodes (45, 46) are provided in the reaction chamber (12), which is/are electrically conductively connected to a power source (47).