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Nest Thermostat Installation Tips (2nd Generation)

I've been looking to add a Nest Thermostat to the house for years.  I'm probably the only person in our house that enjoys voice commands, but being able to voice control the thermostat is something I want to do. This weekend an awesome neighbor that had a spare Nest, let us borrow one to see if we like it. 

The unit I'm borrowing, pictured above, is a 2nd generation device. 3rd generation Nest thermostats are currently in stores with rumors of a new version around the corner.

Of course the industrial design is really good, but I want to briefly share my installation experience in bullet form:
  • Installation isn't physically hard. Nest includes a screwdriver that will help you remove your old unit and install your Nest thermostat. The white plate in the picture above is included in the box. This plate eliminates the need to patch holes or paint when removing larger thermostats.
  • Getting the wiring correct is another more difficult story that required trial and error. For example, it seems like my unit is working fine without the "common" wire. My previous thermostat used the "common" wire, but the Nest complained about it. Most posts I've read strongly encourage connecting the "common" wire. 
  • Speaking of wires, the main power source connects to either RC or RH. The installation manual seemed to imply you could use either. When connected to RC my unit blew hot air even when it said it was cooling. I'm currently running the unit connected to RH, but I'm already wondering what will happen when it gets cold and I need to turn on the heat. You can see my current wire configuration below.
  • Nest has an embedded battery to maintain device state, but what's really strange is that a low battery level greatly limits the ability to software configure the device. I suggest charging your nest with a micro USB if you have a low battery warning. 
  • While troubleshooting issues, it seems like many of the current articles reference features that require a software update. However, you can't even connect the device to wifi with a low battery warning. Furthermore, once you get connected to wifi, the device says, "new firmware available and it will be installed within the next day." So you are waiting for the latest and greatest software with no way to force the update.
  • Somewhat minor, but I had to create a Nest account. Despite being owned (for now) by Google, I wasn't able to use my existing Google account. 
Granted I'm testing with a 2nd generation loaner device, but I spent way more hours than I anticipated on the setup. Installation was quick. Setup was long and left me guessing. I'll give this loaner Nest a few days and see how it goes. Based on setup alone and limited exposure to using it, I'm not convinced it's necessary. 

My wiring setup: