What is the color code for a thermostat?

This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).

What are the wire colors of a thermostat and their function?

Red – Rc – 24VAC (dedicated to heat call) Red – Rc – 24VAC (dedicated to cooling call) Green – G – Fan. White – W – Heat.