For HVAC applications in heat-generation environments, type-tested thermostats are ideal. There are a variety of thermostats available, including safety temperature monitors, aka STM, temperature regulators, double thermostat TR/STL, and safety temperature limiters.
Single thermostat models include Types 5345, 5344, and 5343, and double thermostats include types 5349, 5348, and 5347.