Nest Thermostat vs Learning Thermostat with not C Wire

[andre51]

I have a Nest Thermostat, and when I installed it, the system recommended adding a C-wire or Nest Power Connector for proper functionality. For reference, my system has R, Y, W, and G. The Nest compatibility checker is a bit confusing in that it explicitly warns that the some may find that Nest Thermostat needs a C Wire or Nest Power Connector. However, in the compatibility checker website, the Nest Learning Thermostats do not give that warning. 

Does that mean, that if I buy and install a Nest Learning Thermostat 4th Gen it will work just fine without a C-Wire or Nest Power Connector. Or will it still limit features or possible malfunction without them? Is there a sure-fire way to know before purchasing?

[moralesvicente]

Hello andre51, 

Thank you for contacting the Google Nest Community Forum. I understand you're asking whether the Nest Learning Thermostat (4th gen) requires a Nest Power Connector or a C-wire, unlike your current Nest Thermostat. I'm happy to provide more information.

Nest Thermostats are designed to use very little power and can often draw enough consistent power directly from your system’s heating and cooling wires. However, some systems may require a common wire (C wire) or a power accessory like the Nest Power Connector to ensure compatibility.

While the Nest Learning Thermostat (4th gen) often doesn't need a C wire to function, it's not guaranteed. Its necessity depends on your specific HVAC system or the current voltage. During the initial setup, the app will automatically perform a power test and inform you if a C wire is required for your particular system.

Let me know if you have more questions. 

Best regards, 

Daniel

[andre51]

Does the fact that my current Nest Thermostat requires a Nest Power Connector for full functionality give any evidence that the Nest Learning Thermostat will need one to function properly? Or are the electronic of the thermostats different enough that one is unrelated to the other?

[moralesvicente]

Hey andre51, 

Thanks for getting back to me. Regarding your concern, the Nest Learning Thermostat (4th gen) is more likely to work without a C-wire or Nest Power Connector than your current model because it features a larger internal battery to manage power fluctuations. While I can't guarantee compatibility until it's physically installed, this model offers the best chance of operating without an additional power accessory.

Regards, 

Daniel