We've got full radiant in the house, with tubes in slab in the basement and warmboard on the first & second floor. Each floor is a zone, and the system runs off of a 48 gallon buffer tank heated by a 3 ton synergy 3 system. The house is ICF, so it's well insulated and the warmboard system generally heats up pretty fast. The thermostats that were originally installed are those terrible viega dial models - they don't tell you the temperature, they only go on when you turn the dial which tells you the temp is lower than the setting. They seem to go on in a range of 3 - 4 degrees, which is a huge amount of inaccuracy for a radiant system. I'm looking to replace the thermostats on the warmboard floors. I'd like something with some radiant smarts, that can track the temp of the floor, that can figure out the reaction time for the system, that displays the air (and maybe slab) temp, that is accurate, and looks nice. What models would meet this requirement? Thanks

What are the stats controlling? What type of valves are they opening? Is there a system controller?

The system is controlled by a Taco 4 zone valve controller (ZVC 404). The thermostats are connected to the Taco, which actuates 3 caleffi Z-one Zone Valves. The buffer tank directly triggers the synergy for heat.

You might consider outdoor reset or some type of learning thermostat to keep the buffer tank at a lower temperature when little heat is needed. Cooler tank means more efficiency and less overshoot.

The buffer tank is also an indirect water heater used to preheat our domestic water, so I don't want it to go too low. I do plan on doing a manual reset at the onset of spring, adjusting it from 110 down to 90 or so, and then adjust it back up in fall.