A dishwashing appliance includes a tub defining a wash chamber. The dishwashing appliance also includes an inlet defined in the tub and providing fluid communication into the wash chamber. A sump is positioned at a bottom of the wash chamber for receiving fluid from the wash chamber and a heater is in operative communication with the sump. The dishwashing appliance also includes a heat pipe heat exchanger having a condenser section and an evaporator section. The condenser section in operative communication with the wash chamber and the evaporator section is in operative communication with the sump.