A method for adjusting the setpoint temperature of a heat transfer medium circulating in a heating or cooling system (9) inside a building or at least inside a surrounding part of a building. The heating or cooling circuit includes a plurality of heat transferring units, each with a temperature controlled valve. A sum opening degree (OD) of all temperature controlled valves is determined in a time dependent manner and a setpoint temperature Tw,ref of heat transferring medium is controlled according to a predetermined sum opening degree (OD) of all temperature controlled valves. A heating system (9) is provided for supplying heat to a building or a part of the building via a liquid heat transfer medium circulated in a circuit. The heating system (9) includes heat transferring units, each being equipped with a temperature controlled valve. The system is controllable according to the method for adjusting the setpoint temperature.