My parents house originally had the hole in the floors for heat (original coal heat, Victorian). Parents upgraded to forced air when they bought it....A family member bought a house that came with three thermostats and no instructions. I figured it out for them. Cool system. One thermostat on main floor was furnace. Second thermostat in lower-level (wo basement) controlled inlet air damper on wood stove. Third thermostat on main level controlled a transfer fan to suck heat out of room with wood stove. Old school hole in the floor would have been simpler and worked without power but it was kind of cool.
My fathers name was not Kevin but he went with what he knew... That heating hole was covered with "some wood" and sheet metal with the W2W carpet over it (you could hear it pop when you walked over it). My mother once tried to refinish/restore the painted kitchen cabinets, only to find out they were full of bondo, actual bondo...