Thanks for the reply. What are your feelings regarding reliability between the two systems? Are the communicating systems ready for prime time or am I asking asking for trouble?

The Lennox quote did not include new thermostats. I asked about a new quote. He had mentioned that 1 thermostat could control system and then sensors placed where the other three thermostats are now. I can adjust temp from any of these sensors for that zone.

Lennox offers a $700 rebate if I buy a thermostat with the system. I had originally gotten the quote through Costco but he can re-quote w/o Costco for me to get the rebate.

Communicating systems are just another level of a possible problem. This is how these systems are designed to be able to deliver the performance as to how they were designed. So if you go with a legacy thermostat the systems performance is no where near what it would be with the communicating thermostat.

From your reply it sounds like you have a zone system, this is likely why they didn't include the thermostats as that zone board that controls your current system is not likely to work with the communication signal.

This reason is partly why I chose Bosch inverter over the others as there is no proprietary signal to get it to work. I also have a zone system. It's not saying you can't have a zone system, just that the zone system will again be another proprietary layer of controls that cost more money to get the system to work as designed from the factory.

The Lennox inverter does provide legacy control, so it's not to say that it won't operate with legacy control. However, from what I can see you give up some operational functions by doing so.

Given this system is tied to a zone system / what those trade offs are isn't exactly clear.

Communication has to do with algorithmic control. All the pieces communicate with one another, the unit knows the set point temp, the actual temp, humidity, temp outside based on all those inputs so that the equipment then can make decisions on 1% increments up and down, maintaining comfort levels.

Non communication equipment like Bosch does things differently, the smarts are all in the outside unit. It knows out door temp then translates refrigrerant pressures / converted to temp as opposed to relying on a thermostat to "communicate" that info.

The Bosch learns, constantly evaluating. The advantage in the Bosch is primarily no need for specialized controls to get the system to perform "as designed".

It's typically not recommended to shop these kinds of things from a big box store as that box store is going to get a cut of the job. It might be in the realm of 10 to 20 percent of the job.

If this company is willing to shyster costco out of their commission? What else would he do?

I would continue to do some more home work if I were you.

I service the Katy, Texas area.