Communicating HVAC system

Next spring, I plan to replace my HVAC system: Furnace and AC. I have two zones which are controlled by ecobee3 thermostats. I’ve been generally happy with these thermostats, and I was hoping to keep using them with new system. However, I learned that the most efficient and green systems are now all controlled by proprietary communicating thermostats. For example: regular thermostat cannot control modulating furnace gas valve, and only is able to do two stages. The same for AC: no variable speed compressor control, only up-to two stages.

I found the following incompatible HVAC systems from various manufacturers:

  • Carrier: Infinity
  • Bryant: Evolution
  • Amana, Goodman and Daikin: ComfortNet
  • Trane and American Standard: ComfortLink II
  • Rheem and Ruud: Comfort Control System
  • Lennox: iComfort
  • Maytag, Tappan, Westinghouse and others: iQ Drive
  • Heil, Comfortmaker, Keep Rite and others: Observer
  • Armstrong Air: Comfort Sync
  • York: Affinity
  • Luxaire: Acclimate
  • Coleman: Echelon

I hate going to proprietary thermostats as it is a regression. There is also ClimateTalk standard, that supposed to solve the communicating thermostat problem, but I do not think anyone is actually using it (am I wrong?).

Which of the above standards work best with Home Assistant, should I just ignore the communicating systems, and buy less efficient two stage systems instead?

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Did you ever figure anything out with this? I am just now starting to look at integrating thermostats and have the same issue. I have Amana and therefore the ComfortNet thermostats.


Unfortunatly, discussion never started. I ended up deciding to use non-communicated thermostats with a new system (i am going with Carrier), so I will have two-stage heat, and cool, but unfortunatly no modulation.

@soleen I recently installed a Fujitsu heat pump and I’m running into the same situation now. They make a module to allow 3rd party thermostats to interface, but it knocks out the variable speed, inverter function, etc. (is my understanding).

How much of a difference do you really think it makes? I’m really wanting to throw an Ecobee on this thing, but feel like I’m giving away a chunk of my investment in the new system.