Here’s a ready-to-use about the Nest Thermostat Wiring Diagram for 4 Wires . You can publish it as is or adapt it for your site. Nest Thermostat Wiring Diagram: 4 Wires Explained (Step-by-Step) If you’re upgrading to a Nest Thermostat (Nest Gen 3, Nest E, or Nest Learning Thermostat) and only have 4 wires coming from your wall, don’t worry. Four-wire setups are very common for low-voltage HVAC systems — usually heat-only or cool-only with a fan.

But to get it right, you need the correct wiring diagram. Let’s break it down simply. | Wire Label | Traditional Color | Function | |------------|------------------|----------| | R or Rh | Red | 24V power (heating) | | Rc (if separate) | Red | 24V power (cooling) | | W or W1 | White | Heat signal | | Y or Y1 | Yellow | Cool signal | | G | Green | Fan control | ✅ For 4-wire setups, you typically have: R, W, Y, G . That means you have both heating and cooling + fan control — no C-wire (common wire) for continuous power. 📄 Nest Thermostat 4-Wire Wiring Diagram Here’s the correct mapping:

Got a heat pump or different wire labels? Leave a comment or check Nest’s compatibility checker.