A method for operating a heating system in a building with at least one heatable room (R1), said heating system comprising: - at least one radiator (HK1) in each heatable room (R1), said at least one radiator (HK1) comprising an actuator (V1) for setting a volumetric flow through the radiator (HK1); - a heat generator (WE) for heating a carrier medium that flows via - a supply (VL) to - said at least one radiator (HK) and flows via - a return (RL) back to said heat generator (WE); - a pump (P) arranged in said supply (VL) or return (RL) for pumping the carrier medium; - a temperature sensor arranged in said supply (VL) for determining a supply temperature ( T VL ) of the carrier medium; - a temperature sensor arranged in the at least one heatable room (R1) for determining an actual room temperature ( T R ) of the room (R1); - a control device (Z) regulating or controlling said heat generator (WE) in order to adjust the supply temperature ( T VL ) of the carrier medium to a predetermined supply target temperature ( T VL,W ); and - a room temperature controller for controlling the room temperature by adjusting an actuator opening ( H akt ) of said actuator (V1) as a function of a predetermined target room temperature ( T R,W ) and the determined actual room temperature ( T R ), said method comprising the steps of: - detecting a current actuator opening ( H akt ) of said actuator (V1) of the at least one radiator (HK1); - determining the target supply temperature ( T VL,W ) as a function of the current actuator opening ( H akt ) of said actuator (V1) of the at least one radiator (HK1); characterized in that said method further comprises: - determining a set of control parameters ( K p , K i ) for operating the room temperature controller as a function of the current actuator opening ( H akt ) of said actuator (V1). - at least one radiator (HK1) in each heatable room (R1), said at least one radiator (HK1) comprising an actuator (V1) for setting a volumetric flow through the radiator (HK1); - a heat generator (WE) for heating a carrier medium that flows via - a supply (VL) to - said at least one radiator (HK) and flows via - a return (RL) back to said heat generator (WE); - a pump (P) arranged in said supply (VL) or return (RL) for pumping the carrier medium; - a temperature sensor arranged in said supply (VL) for determining a supply temperature ( T VL ) of the carrier medium; - a temperature sensor arranged in the at least one heatable room (R1) for determining an actual room temperature ( T R ) of the room (R1); - a control device (Z) regulating or controlling said heat generator (WE) in order to adjust the supply temperature ( T VL ) of the carrier medium to a predetermined supply target temperature ( T VL,W ); and - a room temperature controller for controlling the room temperature by adjusting an actuator opening ( H akt ) of said actuator (V1) as a function of a predetermined target room temperature ( T R,W ) and the determined actual room temperature ( T R ), - detecting a current actuator opening ( H akt ) of said actuator (V1) of the at least one radiator (HK1); - determining the target supply temperature ( T VL,W ) as a function of the current actuator opening ( H akt ) of said actuator (V1) of the at least one radiator (HK1); - determining a set of control parameters ( K p , K i ) for operating the room temperature controller as a function of the current actuator opening ( H akt ) of said actuator (V1). <EOS>