So pex can take 180, good , can the floor , can your Feet. At 180 you
could put a pot of beans and a pot of stew on the floor and have it
cooked when you awake. I think crock pots cook at 160. Radiant floor
should be warm , not hot. Ive lived with radiant and the floor was a
comfortable Warm.
My point is they need a pro to calculate load and plan it and do it
right. It may need its own loop, tempering, thermostat and pump as the
radiators will operate at a higher temp with more mass. When you mix
systems, ex. Large cast iron radiators, baseboard, radiant, or fan
forced HW heat on the same system unless you know the trade mixing often
means uneveness in heat. The previous owner of my residence removed cast
iron radiators in one room to make for more room and put in high out put
fan forced heaters , but he forgot radiators hold heat for an hour, so
the room never stayed warm. So I ripped them out and brought back in the
original and all is fine. Im just pointing out a pro is needed to be
sure it is done correctly. Hacked in it will be bad.