System for operating a heating unit in a building having a plurality of rooms to be heated, comprising: at least one heat exchanger per room to be heated, a heating unit having at least one heat generation unit for heating a carrier medium which flows via a feed line (VL) to the at least one heat exchanger and via a return line (RL) to the heat generation unit , and a heat distribution unit , a pump arranged in the feed line (VL) or in the return line (RL) for circulating the carrier medium, a control device for controlling the heating unit , a plurality of setpoint value transmitters which each provide a setpoint temperature T n,soll for the plurality of rooms to be heated, at least one temperature sensor per room to be heated for determining an actual temperature T n,ist of the room to be heated, the control device is set up to control the heating unit as a function of a maximum difference Δ T max = max n Y T n , soll − T n , ist , X n and additionally as a function of the setpoint temperature T n,soll of the one room to be heated or of the plurality of rooms to be heated, wherein: Y is a function as a function of the setpoint temperature T n,soll of a room n of the plurality of rooms to be heated, the actual temperature T n,ist of the room n, and a parameter X n , which comprises a value of the area of the room n to be heated, a value for a volume of the room n to be heated, a value as a function of the exposure of the room n, a value as a function of a weather forecast and/or a value as a function of weather data, and the maximum over the plurality of rooms to be heated of the building is determined. at least one heat exchanger per room to be heated, a heating unit having at least one heat generation unit for heating a carrier medium which flows via a feed line (VL) to the at least one heat exchanger and via a return line (RL) to the heat generation unit , and a heat distribution unit , a pump arranged in the feed line (VL) or in the return line (RL) for circulating the carrier medium, a control device for controlling the heating unit , a plurality of setpoint value transmitters which each provide a setpoint temperature T n,soll for the plurality of rooms to be heated, at least one temperature sensor per room to be heated for determining an actual temperature T n,ist of the room to be heated, the control device is set up to control the heating unit as a function of a maximum difference Δ T max = max n Y T n , soll − T n , ist , X n and additionally as a function of the setpoint temperature T n,soll of the one room to be heated or of the plurality of rooms to be heated, wherein: Y is a function as a function of the setpoint temperature T n,soll of a room n of the plurality of rooms to be heated, the actual temperature T n,ist of the room n, and a parameter X n , which comprises a value of the area of the room n to be heated, a value for a volume of the room n to be heated, a value as a function of the exposure of the room n, a value as a function of a weather forecast and/or a value as a function of weather data, and the setpoint temperature T n,soll of a room n of the plurality of rooms to be heated, the actual temperature T n,ist of the room n, and a parameter X n , which comprises a value of the area of the room n to be heated, a value for a volume of the room n to be heated, a value as a function of the exposure of the room n, a value as a function of a weather forecast and/or a value as a function of weather data, and the maximum over the plurality of rooms to be heated of the building is determined. <EOS>