query: Who invented the thermostat?
passage: Thermostat
Warren S. Johnson (1847–1911) of Wisconsin patented a bi-metal room thermostat in 1883, and two years later filed a patent for the first multi-zone thermostatic control system.[5][6] Albert Butz (1849–1905) invented the electric thermostat and patented it in 1886.
passage: Wax thermostatic element
The wax thermostatic element was invented in 1934 by Sergius Vernet (1899–1968). Its principal application is in automotive thermostats used in the engine cooling system. The first applications in the plumbing and heating industries were in Sweden (1970) and in Switzerland (1971).