How can I view aux/stage status for Honeywell T6 thermostats?

I’ve recently installed a T6 thermostat to control my heat pump and I’m having difficulty figuring out how to monitor when the heat thermostat enables the AUX heat to supplement the Stage 1 heat cycle. The information is available directly on the thermostat, but I can’t figure out how this would be getting reported via ZWave… any suggestions?

If your device supports the Thermostat Operating State V2 command class it can report this. If not, I don’t think it’s possible.

You can check by downloading the device diagnostic file from the device page. Feel free to post the file if you don’t figure out the contents.

Even if supported by the device, HA does not support this. This can be worked around with a template, but the device needs to support it first.

Within the diagnostic logs file, I’m getting this whenever Stage 1 is active, regardless of whether it is receiving supplemental AUX:

        "12-66-0-state": {
          "endpoint": 0,
          "commandClass": 66,
          "commandClassName": "Thermostat Operating State",
          "property": "state",
          "propertyName": "state",
          "ccVersion": 1,
          "metadata": {
            "type": "number",
            "readable": true,
            "writeable": false,
            "label": "Operating state",
            "min": 0,
            "max": 255,
            "states": {
              "0": "Idle",
              "1": "Heating",
              "2": "Cooling",
              "3": "Fan Only",
              "4": "Pending Heat",
              "5": "Pending Cool",
              "6": "Vent/Economizer",
              "7": "Aux Heating",
              "8": "2nd Stage Heating",
              "9": "2nd Stage Cooling",
              "10": "2nd Stage Aux Heat",
              "11": "3rd Stage Aux Heat"
            },
            "stateful": true,
            "secret": false
          },
          "value": 1
"ccVersion": 1,

Version 1 doesn’t support it.

Ah, bummer. I guess the workaround then is CT clamps… Now to figure out how to get the home energy monitor wired up, because it looks like the wires for the CT clamps might not be in-wall rated…

I’ve had success putting a CT clamp on the 24vac control wires, these may be easier to get to.