Using a heating system is absolutely necessary in areas where the temperature is always around 15 degrees Celsius. The difference between a floor heater and a radiant heating system is that with the first one the area heated is the floor and the mid air of the room while with the second one all the heat rises to the ceiling leaving the floor cold.
The system uses a boiler to heat water, which is also the source of heat, and then this water is carried through PVC pipes through the rooms.
The floor over the under floor heating system can be of any type. The best is still the wooden floor because it helps at proving a uniform insulation. The other preferred type is carpet. The maximum temperature reached will differ with the type of flooring used.
If you decide to install the system after the construction of the building is finished, then it will require a lot of destruction. You can do it yourself but a job done by a professional is always better. The same thing applies to installing the insulation.