I've experimented w/that (based on a suggestion and lots of help from @aaiyar) using Honeywell T6 and a Zen Zigbee thermostats, and it works techically...but it's dicey if you have others in the house (i.e., my wife) who don't want to have to remember not to try to use the controlled physical thermostat mounted in the hallway outside the HVAC closet. Just didn't like that at all.
So I think the only way it will work for me is:
Z-Wave or Zigbee thermostat connected to HE and the HVAC, but hidden inside the closet HVAC closet. This is the controlled thermostat.
Z-Wave or Zigbee thermostat connected to HE on the wall in the original thermostat's spot, not connected to HVAC. Any changes on this thermostat are mirrored via Rule to the thermostat controller controlling the first thermostat that is connected to HVAC.
Might add third Z-Wave or Zigbee thermostat in my wife's office so she can manage temps as desired from there as well. Wanted to set up a dashboard for her to control settings or even push/hold buttons on a Pico that would increase or decrease cool or heat temps by 2 degrees at a time, but she didn't like that for some unfathomable reason. She loves Picos, but evidently not for this purpose.
Aside from a custom app (which I'd like to try if one is created) this seems like the only way I'll ever get to use Thermostat Controller to set up cooling and heating in different parts of my house based on temps and occupancy.
Aye, Thermostat Controller needs to be fixed to recognize and handle properly manual events from the real thermostat. Without that (and without buying multiple thermostats), it's not usable in a house with humans who rightly expect that the buttons on the thermostat must always have priority. We'll have to wait for either the source code or the fix.
Don’t wait for the source code. Closed source means closed source. I don’t speak for anyone at Hubitat but it’s clear from previous statements that staff have made, that’ll never happen.
What do you think the interpretation for such an event should be? Does it just become another way to set the Controller Thermostat? What if you don't want the Controller Thermostat to be changed by this?
Perhaps an option: "Allow Controlled thermostat changes to set Controller Thermostat" ??
This is not at all as simple as it appears at first blush. Thermostat Controller uses the Control Offset to set the Controlled Thermostat degrees above or below the desired setpoint for the Controller Thermostat, thus forcing it into heating or cooling. When the Controller Thermostat demand is satisfied, it sets the Controlled Thermostat setpoint the opposite direction to force it to stop heating or cooling. So at any given moment, adjusting the Controlled Thermostat will not be an obvious thing to do for someone not familiar with how it works. How would you propose overcoming this for "humans who rightly expect" things to work the way they have before?
In reality, unless the other humans in the house come to understand that adjusting the Controlled Thermostat is NO LONGER the right way to adjust things, this will fail from human factors problem. One fix is what @danabw does. Another fix would to be a wall mounted mini-tablet with a Dashboard displaying the Controller Thermostat, and eduction of household members that this is how heating/cooling are adjusted. There third fix is not to use Thermostat Controller if there are other people in the house who can't learn what to do. Dashboards with the Controller Thermostat can be put on any phone, tablet or computer in the house.
Indeed, you describe Thermostat Controller as operating in a way that makes the controlled thermostat set point meaningless, because the Controller manipulates the set point of the controlled thermostat to turn on/off the heating/cooling. The controlled thermostat set point does not reflect when the heat/cool will actually trigger; the actual trigger set point information is only known inside the Thermostat Controller. What is visible on the controlled thermostat is irrelevant; it's just a value set by the Controller to turn on/off the heating/cooling.
Using Thermostat Controller, the set point visible on the controlled thermostat is meaningless (only the Thermostat Controller knows the real set point). That makes the buttons on the controlled thermostat equally meaningless.
Since this is the way Thermostat Controller works, the Controller can't be used if you want the real thermostat set point to mean something (and thus the buttons to mean something). If you want the real thermostat to show a meaningful set point and to have the buttons meaningfully change that set point and affect heating/cooling, then don't use Thermostat Controller.
In cases where people have kludged in a second thermostat, not connected to HVAC, to trigger Rules for its buttons and adjust the Controller set point, there may be a disconnect between what that second thermostat shows and what actually happens, especially if Thermostat Controller is averaging temperatures from multiple places.
One might adjust the set point on the second thermostat to be a few degrees higher than the temperature on that thermostat, hoping to turn on the heat, only to find that the Thermostat Controller refuses to turn on the heat because the new set point is actually still below the Thermostat Controller averaged temperature from the multiple temperature inputs. So the second thermostat buttons might look like they were being ignored because they didn't change the set point enough to convince the Thermostat Controller to do anything.
Given that the Controller Thermostat is virtual, it can have a presentation as such for human interaction. It does behave the way one would expect a thermostat to behave. The temperature it displays as the current temperature is the weighted average of the temperature sensors, and its setpoints control the real thermostat with respect to achieving that computed temperature to be as set.
So, a Dashboard makes a reasonable way to present this Controlled Thermostat, while a physical thermostat does not.
As I became more familiar with home automation it became clear that a light switch is an unnecessary anachronism. This is equally true of a physical thermostat as a human interface point. One just hopes that the placement of the physical thermostat as a temperature sensor has been done wisely. It's control interface resides there, but could reside anywhere.
Yes, I see that now. If physical thermostats could decouple what is being displayed from what the HVAC is doing, allowing an intermediary to make the connection, they could be used with a Controller. If a Thermostat Controller could control the HVAC without altering the displayed set point on the physical thermostat, and if the displayed set point and displayed temperature could be sent to the physical thermostat from the Controller (allowing the physical thermostat to display the internal state of the Controller), then a real thermostat could be an interface to a Controller. But because physical thermostats control the HVAC by comparing the set point to the local ambient temperature, and because you can't set the displayed ambient temperature in a physical thermostat, physical thermostats are not useful human interaction devices under a Thermostat Controller. If you use a Controller, find a way to prevent access to the physical device being controlled, since its display is meaningless. (Even the displayed temperature is misleading, since the temperature in that one location may be only one of several temperatures being used by the Controller internally, and it's that averaged internal temperature that should be displayed.)
