My old thermostat has wiring going to W, RH, RC, G, Y and jumper between RH and RC. After I scan the QR code, Google Home App says the device is not Compatible. Does it mean it will not work even with a C wire or Power module. Not very clear
Your current thermostat has a standard configuration. Without a C wire, the basic Nest Thermostat will work since it uses two AA batteries.
Here is then link to the Nest Compatibility checker: https://store.google.com/us/widget/compatibility/thermostat
The AC Cooling Wizard.
@CoolingWizard, thanks for the help!
@Giri1, I'm glad to hear that your Nest Thermostat is working fine. I will be locking this thread in 24 hours. Please feel free to create a new thread should you have some more questions or concerns in the near future and we'll be more than glad to help.