Turn off the power supply to the heating or cooling system
Let the system cool down if it has been running
Remove the old thermostat cover
Take a photo of the existing wiring
Label each wire before disconnecting it
Disconnect the wires from the old thermostat
Remove the old thermostat base from the wall
Check the wall and wiring for damage
Mount the new thermostat base level on the wall
Pull the wires through the new base opening
Connect each wire to the correct terminal
Tighten all terminal screws securely
Attach the thermostat display or cover
Restore power to the system
Set the thermostat to the desired mode
Test heating and cooling functions
Recheck wiring if the thermostat does not work
Secure the thermostat firmly once confirmed working