The invention relates to a method for operating a circuit having a heat accumulator, having a coolant circuit, having a heat accumulator in a line of the circuit and having at least one valve and one pump, wherein, when the valve is open, the heat accumulator can be charged with coolant from the coolant circuit by means of the pump, or coolant can be discharged from the heat accumulator into the coolant circuit, wherein the charging or discharging of the heat accumulator takes place in an open-loop-controlled or closed-loop-controlled manner as a function of a temperature difference of a temperature of the coolant in the circuit and a temperature of the coolant in the heat accumulator.