What is a thermostat c wire or common wire?
The c wire or common wire for your thermostat allows the thermostat to receive power from your furnace or air conditioner. This powers your thermostat, and is required for most wifi and smart thermostats.
General
What is a thermostat?
What is a thermostat? – This is article will explain what a thermostat is and give example of different types of thermostats