If your thermostat has power related issues, like the battery draining too quickly or Wi-Fi constantly disconnecting, you can typically fix them by connecting a common wire (C wire) or by installing the Nest Power Connector. Either one will provide a stable power source for your Nest thermostat when your system can’t deliver enough consistent power to it.
If your system already has a C wire or a spare wire, you can simply connect it to your thermostat and HVAC system. If there isn’t a C wire, you have 2 options: get a pro installer to run a new C wire from your system to your thermostat, which can be expensive, or you can install the Nest Power Connector, which is usually simpler and more affordable.
If you don’t feel comfortable installing the Power Connector yourself, you can contact a pro to install it for you.
The Nest Power Connector works with these Nest thermostats:
- Nest Thermostat
- Nest Learning Thermostat (3rd gen)
- Nest Thermostat E
- Nest Learning Thermostat (4th gen)
For more information, refer to How to tell which Nest thermostat you have.
How to tell if you need the Nest Power Connector
Use the interactive tool to check if you need a Nest Power Connector with the compatibility checker.
Cases that may require power connector installation or a C wire:
- During thermostat setup, the Google Home app tells you that you need the Power Connector or a C wire.
- Your thermostat screen shows a power-related help code, such as E1, E297, N260, N261 or M27.
- Your thermostat screen shows “Very low battery. Replace now and install stable power source.”
- Your thermostat battery keeps draining.
- Your thermostat repeatedly disconnects from Wi-Fi.
- Your thermostat isn’t getting enough power and disables the following features:
- Remote sensor
- Matter support
- Occupancy detection
- Wake-on display
- Farsight
For a more extensive list of symptoms, go to How to tell if your Nest thermostat needs a C wire.
Note: If the app tells you that you do need the Nest Power Connector during installation, you may need to exit set up until you have received the connector.
How to install the Nest Power Connector
You can install the power connector yourself, or call a pro. For a brief video of the installation process, go to How to install the Nest Power Connector.
Note: If your system doesn’t have a C terminal, you’ll need to call a pro.
Before you start
- Finish installing your Nest thermostat before you install the power connector.
- Update your thermostat if needed. To check for available updates:
- Make sure your thermostat is set to Off mode.
- On your thermostat, select Settings
Software or Version
Software or Version 3. If the C wire information that was entered in the app is incorrect, update the wiring info:
Home app
- Open the Home app
.
- Tap and hold your device's tile.
- At the top right, tap Settings
- Update any incorrect wiring information.
.
Nest app
- Open the Nest app
.
- Tap Thermostat
- Update any incorrect wiring information.
4. Turn off power to your system at the fuse box or system switch. This prevents damage to your system and helps keep you safe.
5. Check if you’ve turned off the right breaker by changing the temperature with your thermostat. Wait a few minutes to make sure your HVAC system doesn’t turn on.
Where to install the Nest Power Connector
- If your home has one thermostat, install the power connector at the furnace or air handler.
- If there’s a control board, find the series of labeled terminals on it and install the power connector there.
- If there’s no control board, which is common for heat-only systems, find the thermostat wiring and where it connects to the furnace.
- If you have a zoned system with more than one thermostat, install the power connector at the zone controller. If you can’t locate your zone controller, contact a pro.
Installation guides
Important: Installation will require access to wiring, and may require the use of ladders or working in locations with little space. Use a helper if possible and avoid installing the device when home alone.
Basic installation guide
The Nest Power Connector comes with instructions in the box. Follow those instructions to install the connector. You can find the same instructions in this Installation Guide.
Advanced/Pro installation guide
For more complex systems and for pro instructions, use this Pro Installation Guide.
Troubleshoot installation issues
For more help, contact us or call a pro.