Step 3 · Label Wires

Using the labels provided with your Nest thermostat or small pieces of tape, label each wire according to the terminal it was connected to on the old thermostat (e.g., R, G, Y, W, C). If you don't have labels, you can use small pieces of tape and a pen. Ensure each label accurately corresponds to the terminal designation from your reference photo. This step is vital for ensuring proper communication between the Nest thermostat and your HVAC system.