Showing results for 
Search instead for 
Did you mean: 
Replies are disabled for this topic. Start a new one or visit our Help Center.

The Nest Thermostat G4CVZ battery dies in about a month or two. Why?

Community Member

I installed an entirely new HVAC system two years ago, installed by a professional installer. The batteries die in about a month or two, why? Do you need a Serial number etc.? I just discovered that this model must be installed by professionals only, and troubleshooted by homeowners only. Why is that?

Niranjan Desai

Community Specialist
Community Specialist

Hello NDD61,

Thank you for taking the time to let us know about your inquiry. Happy to shed some light on the situation here.

The built-in battery of Google Nest Thermostats may be recharged over time using the heating and cooling wires. When the Nest Thermostat's battery is unable to recharge itself using the thermostat wires, you must connect the Nest Power Connector or a common wire (or C wire) in order to ensure that your thermostat is consistently powered on. A common wire serves just to maintain the current flow into the thermostat and to supply stable power; it is not responsible for any heating or cooling functions. Installing a C wire or a Nest Power Connector will be necessary if your thermostat experiences power issues or its battery drains regularly.

Feel free to let us know if you have more questions in mind.