I currently have a Google Nest Thermostat downstairs, and it works fine. I want to add a second thermostat upstairs and then have it 'learn' that I sleep upstairs so it should adjust the temperature based on the fact that I'm upstairs at night, but downstairs during the day.

What I'm not sure of is how a single HVAC unit works off of two Nest Thermostats. Is this 'zoning'? Also, the one downstairs is wired, so if I add one upstairs and give it power, does it need to be wired or will it report the upstairs temperature to the one downstairs wirelessly? I'm not sure how you would go about wiring two of these things up if that's what is necessary.

  • 3
    Have you contemplated using one of their remote sensors instead?
    – Jon Custer
    Jan 18, 2023 at 15:40
  • 1
    I have an Ecobee thermostat with remote sensors, and for each programming chunk, you can tell it what sensors to use. So in the day, it can use the main temp, and at night, it can use an upstairs sensor. Nest may have similar functionality.
    – JPhi1618
    Jan 18, 2023 at 15:45
  • @JonCuster: I just looked at the sensors, but they are just that, sensors only. There is no way to control the temperature from upstairs aside from a mobile device, or go downstairs to change the temperature.
    – myermian
    Jan 18, 2023 at 16:37
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    @myermian - no, the main thermostat can be taught which input sensors to use to control the furnace to make which room comfortable for you at which times.
    – Jon Custer
    Jan 18, 2023 at 16:58
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    @myermian - I'm not sure I fully understand, but... Say you like the room you are in to be at 72F. So you set the main thermostat to 72 and the thermostat turns the furnace on and off to keep the thermostat near 72. But the upstairs room, facing north, with a big window stays colder than 72. So you put a remote sensor there, and have the Nest control based on that sensor. Now the furnace comes on to warm that room up to 72 (and the rest of the house warmer than 72). But you are happy if you are in that room. When you go back downstairs, have it use the main thermostat instead.
    – Jon Custer
    Jan 18, 2023 at 17:34

1 Answer 1


Zoning would describe having each thermostat control a separate part of the house. For example, my system has three zones: upstairs, downstairs, and the one that provides hot water; each has its own thermostat and it's own forced-hot-water pump, with a circuit board that combines the thermostat inputs and manages the boiler itself.

It sounds like you just want to make sure that both locations are at the desired temperature or higher -- which is less efficient but doesn't need heating zones.

As others have said, many of the smart thermostats offer remote temperature sensors as an accessory. Those would be much easier and cheaper to set up than putting in another whole thermostat, especially if you have only one heating zones (or just one plus hot water). How intelligently the system uses these additional inputs varies between manufacturers and models; check your owner's guide for details. An advantage is that you can move these sensors to wherever you're spending the most time; disadvantage is replacing batteries every year or two.

  • Would the sensor allow me to adjust the temperature while upstairs as well, or do I have to go downstairs or use my phone app to change the temperature while upstairs?
    – myermian
    Jan 18, 2023 at 16:32
  • @myermian - see support.google.com/googlenest/answer/…
    – Jon Custer
    Jan 18, 2023 at 16:34
  • Also, no. I don't want both areas at the desired temperature -- that just can't happen in any house I have ever lived at with a single HVAC. I just want to be able to sense and change the temperature when I'm in that area, so it learns when I am typically upstairs (sleeping) and when I am typically downstairs (daytime).
    – myermian
    Jan 18, 2023 at 16:39
  • 3
    The sensor is probably just a sensor; use your phone controls, it set up an old phone to run that app as a control panel .. Learning may be difficult unless the sensor includes occupancy sensing and the software supports that. Being able to program which measurement it pays attention to at any given time if day is more likely. Again, read your user's clues
    – keshlam
    Jan 18, 2023 at 16:59

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