Abstract: A method for operating a heat pump (1) which transfers heat to a fluid heat transfer medium which circulates in a heating circuit is provided. An outside temperature is acquired. When the outside temperature is higher than a limit temperature, a runtime of an electric heating rod (2) of the heat pump (1) and/or energy consumed by the heating rod (2) are acquired. When the runtime exceeds a first limit value within a specified period of time and/or the energy consumed by the heating element (2) in the specified period of time exceeds a second limit value, a message is output.