Important: This article only applies to the Nest Thermostat. Learn how to tell which thermostat you have.
The Nest Thermostat receives power from your HVAC system. It also uses 2 AAA alkaline batteries as a backup, or to supplement if your system can’t deliver enough power.
You can’t replace the batteries for the Nest Thermostat E or Nest Learning Thermostat. Instead, charge the thermostat with a USB cable.
During initial setup, you may get a low battery message. This can happen if the batteries are loose or there’s a piece of the battery tab still stuck to the contacts.
- Pull the thermostat display off the base.
- Make sure you’ve completely removed the battery tab. Pull out the batteries from the back of the thermostat display and check that there are no pieces of battery tab left.
- Reinsert the batteries. Make sure they're fully seated and face the right way.
- Push the thermostat display back onto the base until it clicks into place.
- If the low battery message doesn’t go away, replace the batteries with high-quality 1.5 V AAA alkaline batteries from a known manufacturer.
If power fails and the backup battery is low, your Nest Thermostat will alert you on its display and in the Google Home app. If you get this alert, replace the batteries with new ones.
Tip: If the batteries were recently replaced, remove and reinstall the same batteries. Make sure the contacts are clean and the batteries are seated firmly in them.If you repeatedly get low battery messages from your thermostat, or if there’s another power-related message, you may need to check the C wire connection. If you don’t have a C wire, you may need to install one to provide consistent power to your thermostat and prevent the backup batteries from draining. Some systems, such as heating-only, cooling-only, zone-controlled, and heat pump systems, require a C wire or the Nest Power Connector. For details, go to g.co/nest/cwire.
- To let your thermostat control your system and help you stay comfortable while you check the C wire, replace your batteries first.
- After you put in fresh batteries, learn how to troubleshoot or connect your C wire.
Important: Use only high-quality 1.5 V AAA alkaline batteries from a known manufacturer.
- Pull the thermostat display off the base.
- Remove the old batteries from the back of the thermostat display.
- Insert the 2 new AAA alkaline batteries.
- Push the thermostat display back onto the base until it clicks into place.