A thermostat switch is used to control the mode of a unit, which is the heating or cooling element, and the circulation fan on applicable units. The switch is powered by the accompanying unit, and engages or disengages when the set temperature is reached.
A thermostat switch is commonly used in an electric oven. The user sets the temperature for the oven using a faceplate or dial, and the thermostat switch automatically engages or disengages the heating element when the set temperature is reached. A thermostat switch is also used for home thermostats to engage or disengage the heating or cooling unit when a desired temperature is reached.