Abstract: A washing system provided with a washing container for washing laundry and provided with a heater device for heating water in the washing container. In order to achieve a high energy efficiency the washing container is provided with a water outlet, a water inlet and an external connection extending between the water outlet and the water inlet. A pump unit is provided for pumping water from the water outlet to the water inlet through the external connection. The heater device comprises a gas burning device for heating a helical tube heat exchange portion in said connection. A water filter is provided for filtering the water.