To install a home furnace thermostat, choose the right kind of thermostat for the home’s heating system, remove the existing thermostat, and install the thermostat mounting plate. Assemble the necessary wiring, and install the new thermostat.
Determine whether a mercury contact, mechanical contact, electric or digital programmable thermostat suits the furnace. Turn off the power source before removing the old thermostat. Label and take a photo of the old wires to facilitate easier installation of a new thermostat. Slowly detach the wires, ensuring that they do not fall into the wall. Unfasten the thermostat mounting plate from the wall.
Next, tug the old wiring through the new mounting plate’s opening. Position the plate on the wall so that the wires fit through both the wall’s hole and the mounting plate’s hole without getting tangled. Attach the plate to the two holes on the wall, and fasten the mounting screws.
Connect all necessary wires, ensuring that color-coded wires match correctly with the terminal connections. To connect wires without colors, use the labels and previously taken pictures of the wiring as reference materials. Feed the excess wire into the wall. Finally, attach the new thermostat to the mounting plate, turn on the power supply, and adjust the thermostat controls.