10.5kW for a 700 square foot room is a lot of heat. I'd think keeping it down to 2 to 3 kW would be plenty unless maybe it is the only heat for the space, but even then maybe up to 5k would likely be fine. Don't want to have to wear oven mitts on your feet to walk on that floorA quick Google check indicates 15 watts per square foot is a common upper limit for design.
I have Suntouch brand in my house. They are 12W per sqft. And every square foot of tile doesn’t normally get mat under it, especially if the room has an irregular shape. Actual installed density is likely closer to 10W per sqft.When I built my house and had floor heat in the bathroom, there really wasn't any choice in watts per square foot, the mats were all the same per foot, just different sizes. If it is the type w/ a heating wire laid out on a grid, they might be able to adjust it, but there are standard ways to do these, and it isn't really in the electrician's ability to choose it. It is up to the tile layer and the owner.
I believe the testator also proves the gfci protection. If the stat is just pulling in a relay that powers the heat how do you get the gfci protection? I guess the branch breakers. Any down side to that? You will not a a trip indicator at the tstat.Typically for these larger systems you would get a relay module(s) that you mount in a box(s) by the floor and the tstat controls those. I needed 4 on a recent job because each loop was slightly over half a circuit.
Steven contact a floor mat distributor and ask for tech support. I have had great success with Danfoss but everyone seems to go with a shluter27.5 x 27 great room. Thanks for your advice. I’m still uncertain how.
It's easy. It will have a line-in and line-out just the same. And there will be small contacts to connect the control wire, the same way you would connect the sensor wire.A Schluter rep told me for that size room (20x20) I need a thermostat coupled with a power module. ( 2) 240v circuits, one to the tstat and one to the power module with a low voltage line between the two. The module doesn't have to be on the wall, can be in closet or crawlspace. I've never installed a heated floor with such a module.