Why do you need a special Thermostat for Radiant Heat?

When it comes to radiant heat, you need a thermostat that is easily adjustable and smart enough to not overheat your home.   So, it is best to get one made specifically for radiant heat.   That being said, some thermostats work with a traditional system as well as radiant heat, and you need to ensure the thermostat you are purchasing will work with the type of heat system you own. You must also keep in mind whether your underfloor heating is hydronic or electric.

How many thermostats so you need for underfloor heating?

One of the advantages of radiant heat flooring is the control you can have over different parts of your home by setting up multi-zone areas with separate thermostats.

This is a personal preference, as you can set up the entire system to be controlled by one thermostat.   However, by having multiple zones with their own thermostat, those separate rooms and areas can be adjusted due to their size or inhabitants.