That's a 120V thermostat, Anne. I still have a 120V heater plugged into one of those thermostats in each greenhouse. They are simply back-up heaters, in case my 240V heater(s) might fail for some reason. So far these 120V heaters have not been needed since the 240V ones have been installed. 240V would have to be hard-wired, since the heaters themselves have to be hardwired directly into the house's electrical panel, each with their own breaker.
