A method for regulating a temperature of a combustion medium in a mixing zone of a burner and a method for regulating a burner, in particular an oil burner, a burner performance being modulated. A heating system including a burner, which includes a regulating device, and a regulating device for a burner, in particular an oil burner. The method/system is intended to provide as constant a temperature as possible in the mixing zone during the different operating modes and with changed burner performance. The combustion air flows through a first supply tract in a first operating mode and in adjustable proportions through the first and/or a second supply tract in a second operating mode, and the combustion air is supplied with heat via a heating element, which may be switched on and off, in the first supply tract, and with heat from a combustion zone in the second supply tract.