Thermostats are components of the heating system and fulfil a central task on the radiator: to control the temperature in a room. The lower part of the thermostat is connected to a valve that can be controlled with the thermostatic head. The thermostatic head contains the most important component - the temperature sensor. After the temperature has been measured by the temperature sensor, a preset value or range is set, which must be kept constant. If it is too cold or even too hot, the valve is opened or closed accordingly.

Thermostats can be divided into two broad groups: analogue and digital. With the analogue or manual version, the temperature is set manually. The desired temperature is set indirectly via the digits on the rotary knob. Here, the first stage corresponds to about 13 degrees Celsius room temperature. The third stands for around 20 to 21 degrees Celsius, the fifth for 24 to 28 degrees Celsius. The exact values can vary depending on the model and manufacturer.

With the digital version, the temperature can be set specifically to the desired value. The set value is shown in real time on the display. The digital version works with an electric motor, which makes it more flexible for automation. While simple devices can store times and temperatures, more expensive devices are linked to an intelligent control system. This form of the smart home makes it possible to adapt the heating behaviour optimally to the environment and the users. In addition, temperature settings can also be adjusted on the move via an app on the smart phone.