Thermostat with multiple sensors

We recently added onto our home and in turn added a new AC. I previously had a honeywell prestige iaq that uses redlink to connect to multiple sensors and would average the temprature based on those sensors. My dumb though that I could pick up 2 Nest for the price of an additional IAQ and the nest would work together. It has been a little over a month and i really miss the iaq and the nest is not working well for me in the addition. I need individual room sensors. The new unit controls 2 bedrooms and a bathroom but the nest is in the hallway. As a result it is getting false temperatures from my main unit. I have tried adjusting it a few degrees but it still isn’t functioning well. The bedrooms are either too hot or too cold. The big realization is when you compare how much each unit has ran over the past month. The main unit has ran on average around 10 hours a day where the new unit has ran less than an hour. Without sending a fortune on new thermostats, is there some way that I can get a sensor to interface though Vera to control my nest?

Proper research would have led you back to the same thermostat you had, or the Ecobee3. Anyhow, you’re going to have to add your own temperature sensors, which isn’t going to be cheap and then write all of the logic to handle the variety of cooling and heating issues that you come across. I don’t envy you as I feel it’s going to take a while to get it back the way you expect it to work. If it were me, I’d change the thermostatsubject out for what I knew did what I needed and try to recover as much money as I could on the Nests…

Averaging the temperatures is not going to make all the rooms be at the average … you will still have some rooms that are to hot or to cold.

If you have a single forced Air system and if you want better control you need to do one of two things:

  1. Statically balance your HVAC flow (using dampers that statically restrict the air in some rooms)
    In this case the actual average is close to the room temperature average in multiple rooms.
    The problem is that often the damper settings are different for heating and cooling.
  2. Dynamically balance your HVAC flow (using dynamic dampers, where each room controls the damper position based on the room thermostat, the AC is on if ANY room requires cooling).
    NOTE: You may not be able to close any of the dampers by 100% … that’s because most AC units would not be able to run properly supplying air to only a small fraction of the design air flow.
    (i.e. only 1 of 4 rooms)

NOTE: The new ductless AC units (A Fan Coil unit in each room) are designed to work on a fraction of the house load. But each fan-coil unit works at it’s design spec (Correct Air-flow for coil size/refrigerant flow)

You can use a PLEG based approach that allows you to specify the “Current” thermostat … so at least you are comfortable in the room you select and then have it control the thermostat actually connected to the HVAC system.

Exactly, it’s going to be a trade off one way of the other. Getting the entire house to the exact same temperature is a feat of mechanical engineering at best.

The main thing is I need the temprature averaged from the 2 bedrooms and the hall left out. I have decided I am going to put my old IAQ back in for the main unit and looking at the Honeywell 8000 for the add on unit. It will allow me to use the add on redlink sensors I already have. I have the Redlink internet device too, so I should be able to plug it all into Vera too.

Ecobee 3 will do exactly what you are trying to do. I can’t say enough good things about this thermostat.

I’m getting an Ecobee3 this week. From what I’ve read, it’s the best option for what I want to do. I can use its sensors for occupancy as well as track temperatures throughout the house. I have to remove some restrictions in my ductwork and I may have to install a Helper fan but I’m looking forward to gaining a bit better control over it.