I own a one level home on slab and is fairly open throught with 2 zones of infloor radiant heated via a gas fired hot water tank. One zone is usually set to 21 C or 70, the other anywhere from 18-19 C or 64 - 66 F. When I feel the floors that aren't warm but feel more neutral overall. If it is really cold out and I turn up both zones higher then after a while the floors do feel warm. Is a neutral feeling for the floors meaning not hot or cold seem correct for how this system should work. Floor surface materials are vinyl; ceramic tile, & wood.