- Read the manufacturer's instructions.

- Turn the electricity off to the thermostat.

- Take down the old thermostat and wall plate.

- Keep track of how the wires are connected to the back of your old thermostat.

- Keep the wires from falling back into the wall.

- Put up the replacement wall plate, if there is one.

- Connect the wires from the wall to the thermostat.

- Attach the thermostat face to the new wall plate.

- Turn the electricity back on to the furnace and air conditioner.

- Test the thermostat by causing the furnace and air conditioner to come on at various temperatures.