How to Install a Programmable Thermostat

Installing a programmable thermostat involves turning off power, removing the old unit, connecting wires to matching terminals, and mounting the new thermostat to the wall.

1. Kill the Power First. Switch off the circuit breaker that controls your heating and cooling system. Remove the front cover of your old thermostat, then unscrew it from the wall. Take a photo of the wire connections before disconnecting them. Carefully pull the wires through the wall opening without letting them fall back into the wall.
2. Label Before You Lose Track. Use the labels that came with your new thermostat or masking tape to mark each wire according to its terminal letter (R, W, Y, G, C). Common wire colors are red for R, white for W, yellow for Y, and green for G. Disconnect each wire by loosening the terminal screws on your old thermostat.
3. Mount Straight, Mount Once. Hold the new thermostat's mounting plate against the wall where your old thermostat was located. Use a level to ensure it sits straight. Mark screw holes with a pencil, then drill pilot holes if needed. Secure the mounting plate with the provided screws.
4. Match Wires to Terminals Exactly. Feed the labeled wires through the center opening of the mounting plate. Connect each wire to its corresponding terminal on the new thermostat by wrapping the wire around the screw and tightening securely. Double-check that each connection matches the photo you took earlier.
5. Power On and Program. Snap or screw the thermostat unit onto the mounting plate according to the manufacturer's instructions. Turn the circuit breaker back on and verify the display lights up. Follow the programming guide to set your desired temperature schedules for different times of day and days of the week.