Remove Old Thermostat
Take the face plate off of the old thermostat and remove the mounting screws. This will expose the thermostat base. Carefully remove the wires from the thermostat base. Mark down on a piece of paper which color wire goes to what terminal. It should be red to “R” for power, white to “C” for common, blue to “Y” for cool, and green to “G” for fan. Be sure to tie the wires together so that they don’t fall into the wall.