This is ultimately a fairly simple question about the Ecobee3 thermostat and the wireless room sensor functionality, but I'll explain my situation first.
Twin home, 2 stories + finished below grade basement.
I'm looking at an Ecobee to replace our first floor thermostat. Our HVAC is a forced air attic unit, so the 2nd floor is much warmer than the first floor and basement when the heat is on. (Cooling does fine since the cold air wants to move down naturally) The basement has a gas fireplace (it operates on it's own thermostat-I'm NOT looking for Ecobee to control that) which when on heats the basement very well and even raises the 1st floor temperature decently. Rather than spend the money on a true zoned HVAC system at the moment I'd like to try using the central heat to cover the 2nd floor and set the basement fireplace to a comfortable temperature and allow it to cycle on/off throughout the day, and also set the ecobee to run the fan occasionally to help pull the heated air from the basement to the first floor.
From reading it sounds like the Ecobee room sensors would allow me to turn the HVAC system control over to JUST a room sensor, rather than working alongside the main thermostat unit to average out the house. So I would put the room sensor in an upstairs hallway and set the entire system based on what temperature I want up there. (the other ducts throughout the house will of course still get air when the unit runs to heat the 2nd floor, which is perfectly fine)
to my question---So in this Room-Sensor-only setup, what number does the main thermostat (1st floor) actually display? The temperature of where the room sensor is located (2nd floor), or the actual temperature of the 1st floor?
I ask because I would prefer it to show the actual first floor temperature so I can gauge how well the fireplace is heating the rest of the house and determine if my fake zoning is working, and not becoming a horrible gas wasting mistake...