Method for operating a pump with an integrated heating element for determining the heating efficiency of the pump or of the heating element, wherein the pump comprises: - a pump chamber with an inlet into the pump chamber and an outlet out of the pump chamber, - a pump rotor inside the pump chamber, - a drive motor for the pump rotor, - a heating element being provided on at least a part of a wall of the pump chamber, - a temperature sensor for sensing the temperature of water in the pump chamber, the method having the steps of: A providing water in the pump chamber, preferably a predefined amount of water, B rotating the pump rotor for mixing the water provided in the pump chamber without transporting water out of the pump chamber, C measuring the temperature of the water in the pump chamber with the temperature sensor as a starting temperature, D activating the heating element to heat the water in the pump chamber after measuring the temperature of the water, preferably for a predefined heating duration, wherein the water is mixed or rotated according to step B when the water is heated, E measuring the temperature of the water in the pump chamber with the temperature sensor, F deactivating the heating element, preferably after the predefined heating duration, and determining the maximum temperature of the water during the heating duration or within a maximum of 10 sec after the heating duration, G calculating a temperature relation between the maximum temperature and the starting temperature of the water, wherein these steps A to G are executed in the pump at a beginning of its operation or at one of the first 50 operating cycles of the pump for determining an initial temperature relation, wherein these steps A to G are executed again after 5 to 100 operating cycles of the pump or after 30min up to 20h of summed up heating operation of the heating element for determining a later temperature relation to determine the heating efficiency of the pump or of the heating element by comparing the later temperature relation to the initial temperature relation. - a pump chamber with an inlet into the pump chamber and an outlet out of the pump chamber, - a pump rotor inside the pump chamber, - a drive motor for the pump rotor, - a heating element being provided on at least a part of a wall of the pump chamber, - a temperature sensor for sensing the temperature of water in the pump chamber, A providing water in the pump chamber, preferably a predefined amount of water, B rotating the pump rotor for mixing the water provided in the pump chamber without transporting water out of the pump chamber, C measuring the temperature of the water in the pump chamber with the temperature sensor as a starting temperature, D activating the heating element to heat the water in the pump chamber after measuring the temperature of the water, preferably for a predefined heating duration, wherein the water is mixed or rotated according to step B when the water is heated, E measuring the temperature of the water in the pump chamber with the temperature sensor, F deactivating the heating element, preferably after the predefined heating duration, and determining the maximum temperature of the water during the heating duration or within a maximum of 10 sec after the heating duration, G calculating a temperature relation between the maximum temperature and the starting temperature of the water, wherein these steps A to G are executed in the pump at a beginning of its operation or at one of the first 50 operating cycles of the pump for determining an initial temperature relation, wherein these steps A to G are executed again after 5 to 100 operating cycles of the pump or after 30min up to 20h of summed up heating operation of the heating element for determining a later temperature relation to determine the heating efficiency of the pump or of the heating element by comparing the later temperature relation to the initial temperature relation.