Im planning on putting my HVAC on automation. My builder wants to use the Tekmar 557 (new, same as 552, but with a few more bells). I'd have a few of these in my house. They can be interfaced to several automation systems, via a tN4 controller. He likes these due to the controllers internal programming to adjust humidity and temperature based on inside, and outside feed back. If it changes inside, it adjusts. If it senses a temp drop, and humidity increase outside, it throttles up hear, and cuts humidity.
The system will be a 6-7 zone infloor heat system. (he thinks six inside, plug garage) with AC. Is there a better thermostat? Or would it be better to just put sensors in the zones and let home automation do it?
Yes. There is the Ecobee, also there is the Proliphix Thermostat
One could use an RC-2000 thermostat as well as the outdoor temp/humidity sensor with an Omni/Lumina controller from HAI. The Omni/Lumina controller will allow you to have the I/O logic on HVAC that you and the builder desire as well as the ability to expand into lighting, remote access, etc. This would provide you with a complete system vs. just having the tekmar stuff and then having to add another control/automation system.
Just don't "over engineer" the system. The more you put into them, the more things can go wrong. Remember, at some point you WILL have a no heat situation and Murphys law will make that at 2:00AM on the coldest night of the year. The poor slob that shows up to try and get you running again will probably not have seen any of this.
I plan to use a furnace as backup to the infloor. No price difference when compared to a big air handler. And I can jumper it, but yes most techs to do repairs will be like WTF is this lol.