I just finished installing Wisbro radient floor heat in a 18X35 greatroom with many large windows and two french doors. Half the room is wood floor, the other half is tile. Supplemental heat is supplied by a 35K btu gas fireplace. Tubing was placed under the floor-between the joists, with metal plates. The rest of the house is fhw baseboard heat. The comfort is unbelievable. No one likes to hang out in the old part of the house any more cause it feels too cold (we are in Maine). Go with the radient if you can afford it. It cost me approx $1400.00 for just the parts (wholesale). Although we have a indirect fired hot water heater, the hydronic system does not come off of it...rather we just added another zone to the heating system. Very simple.