– Bellows filled with a substance with a high coefficient of thermal expansion (that is visibly changed its volume even with little heating or cooling). When the air temperature rises, accordion expands and presses on the valve, shut off the water in the radiator. When cooled, everything happens in reverse. " Setting the thermostat temperature, the reaction is carried out using the rotary knob to the temperature scale. It affects the trimmers spring force by changing the pressure of the bellows on the valve stem. Read more here: Hon. Hazel Brandy-Williams. Temperature controllers are able to react to changes in temperature of only 1 C. However, these devices have the heating system of private home and other characteristics, which is not always written on the packaging – the reaction time, depending on the properties of heat-sensitive material filling the bellows. It is this parameter and must be decisive in the choice device. For example, gas-filled thermostats Danfoss RA respond to changes in temperature in just 8 minutes. It's faster than you can feel something. In liquid-heating thermostat response time on average three times more – enough to feel some discomfort. Finally, solid-state thermostat will "wobble" from 40 minutes to an hour and sometimes longer. And if for some warming you probably do not pay attention (Remember the physiology), then as soon as the room will cool immediately will expose the thermostat at a higher temperature. Almost obtain the effect of a manual valve. As a result, the average temperature of the indoor air may be higher than optimal at 2-6 C, and every extra degree – a 5% increase in power consumed your heating system is a private home.