A double pole thermostat is a device for controlling indoor temperature that allows heat to be shut off completely. This is a useful function in homes with central air and alternative energy resources so as to help homeowners better monitor power and heat usage.
A double pole thermostat is outfitted with a circuit break on either end of the heating array. This allows the entire system to be disconnected in a way that eliminates all power going into the heater so that no energy is being used by that system. Such a feature is denoted by an "off" function on the thermostat.