You searched for: “thermostat
thermostat (s) (noun), thermostats (pl)
1. An apparatus for the automatic regulation of heat: Cryostats and pyrostats are two kinds of thermostats which start or stop the amount of hotness.
2. A device used to control the temperature in an enclosed area: In office buildings hotter or cooler air is supplied as necessary to maintain the temperature at the same level as the setting on the thermostat.