Compatibility
Based on Nest’s online compatibility checker data, the Nest Thermostat works with most 24V systems, including gas, electric, oil, forced air, variable speed, heat pump, and radiant. It can control:
• Heating: one, two, and three stages (W1, W2, W3)
• Cooling: one and two stages (Y1, Y2)
• Heat pump: with auxiliary and emergency heat (O/B, AUX, E) • Fan (G, G2, G3)
• Power (C, RH, RC)
• Humidifier or dehumidifier (HUM, DEHUM)
The Nest Thermostat’s * connector can accept only one of these wires: W3, E, HUM or DEHUM.
The Nest Thermostat is designed to work even if your home doesn’t have a common (C) wire. Rarely, installing a new C wire may be required.
Professional installation recommended for:
• Dual fuel systems (heat pump with furnace) • Whole-home humidifiers and dehumidifiers
In the Box
Installation Steps
1. Switch off the power
This protects you and avoids blowing a fuse in your equipment. Adjust the temperature on your old thermostat to make sure your system is off.
2. Remove cover
Some covers pop off, while others need to be unscrewed.
3. Check your system
If your old thermostat is labeled 120V or 240V or has thick wires with wire nuts, your system is high voltage. Not sure? Contact support.
CAUTION: Do not connect Nest to high-voltage wires.
4. Remove any jumper wires
Jumper wires are short wires between two connectors. You won’t need them. An R wire can go into either RC or RH.
5. Label wires
Peel off the labels below and attach them to the thermostat’s matching wires.
Use the white labels for any W3, E, HUM or DEHUM wires. The * connector can only connect to one of these wires.
See two names for each connector on your old thermostat’s backplate?
Tip: Take a picture of the wires on your old thermostat to help you remember.
6. Disconnect wires and remove the base
After removing the base, we recommend gently wrapping the wires around a pen or pencil to ensure they don’t fall back into the hole in the wall.
Remember, the power to your HVAC system must be off to avoid blowing a fuse in your equipment.
7. Mark where screws will go
Use the bubble level to make sure the Nest Thermostat is level.
Use trim plate if needed
You can cover up holes or marks left by your old thermostat with the optional trim plate.
Snap the base and trim plate together, then screw them to the wall.
You’ll find the trim plate in the bottom of the box.
Mounting on an electrical box
Electrical boxes aren’t common, but if you have one, secure the steel plate to the electrical box with two of the short steel plate screws. Insert the screws into the long slots on the steel plate.
Use the other two short screws to attach the Nest base and trim plate to the steel plate.
8. Attach the Nest base
Pull the wires through the center of the base, then attach it to the wall with the screws.
9. Connect wires
After all the wires are securely connected, push them down to make sure they’re flush with the base.
The exposed wire should be straight.
10. Attach the display
Press the display onto the base until it clicks.
11. Switch the power back on
12. Setup and Nest Account
The Nest Thermostat will turn on and walk you through setup. Just turn the ring and press to select. During setup, you can connect the thermostat to Wi-Fi.
Go to nest.com/account or download the Nest app to create a Nest Account.
The app will show you how to connect your Nest Account and thermostat.
Remember, you can download the Nest app from the AppStore or GooglePlay.