Equipment which controls the heating supply in buildings according to outside temperature and time is necessary for the reduction of the energy consumption of heating plants. This equipment can bring about improved comfort and energy savings. For this purpose, outside temperature compensated controllers are necessary. This standard describes the main equipment characteristics and functions of controls required for reaching energy saving and comfort requirements. The DIN EN 12098-3:2014-01 standard resulted from the summary of both the DIN EN 12098-3:2003-05 and DIN EN 12098-4:2005-12 standards. This standard applies to electronic control equipment for heating systems with direct electrical emission. This control equipment controls and regulates the distribution and/or the generation of heat in relation to the outside temperature and time and other reference variables. Moreover, this standard covers controllers which contain an integrated optimum start or an optimum start-stop control function. The controller modulates heating or control modes of electronic individual zone or emitter control equipment. Safety requirements on heating systems remain unaffected by this standard. The dynamic behaviour of the local thermostats, sensors, or actuators is not covered in this standard. A multi-distribution and/or multi-generation system needs a coordinated solution to prevent undesired interaction and is not part of this standard.