Question

What is an antonym for thermostat?

Answer 1

A synonym for thermostat could be a term that has to do with measuring energy. But an antonym for thermostat would probably be something that measures the cold. But you can't measure the absence of energy so there might be no antonym I suppose. 

Answer 2

To be honest there is no answer for that because a thermostat is a measuring device to measure temperature I hope this helps you understand why there is no answer