Heating unit for dishwasher machine

A heating unit (1) for a dishwasher machine is described comprising at least one filter (5) positioned on the bottom of a washing tank (2) of said dishwasher machine so as to collect and to filter the washing water contained in said tank, a tray (8) for the collection of the filtered washing water containing said filter (5), a suction duct (11) that takes such washing water toward a recycle pump (12). The unit comprises a heating element (20, 30) arranged around said filter (5) inside said tray (8) and fastened to the bottom of said tray (8).