You can use it on any type of finished floor. There are a couple of things you want to look out for. With carpet, you want to make sure you stay below a R value of 2.5. Let's say you put a thick pad on top of your radiant floor. Then, you put a thick carpet pad on top of that, and then you put a thick dense carpet on top of the pad. Basically, you are laying down insulation on top of the radiant floor. That is not a good idea. If you have that dense of carpet, the heat is not able to travel up to through your carpet. It will heat up the water more. Typical carpet applications work completely fine. You just want to make sure you check the R value before installing your carpet on top of the radiant floor.
