La Piba and I are trying to work out if underfloor heating should be left on the whole time or controlled by thermostat. I've scoured on line only to find all advice utterly contradictory, often in the same piece of advice, so hoping the brainy bods of the forum are better than that. It's only in the open plan area of the house, kitchen/living room/hall, about 1600 sq ft. with 3 statted control zones. Floor is well insulated and surface is limestone tile, heats up nice and quick and conducts well. probably too much glass, but all triple glazed, and no draughts at all (airtight house). Someone said this being the case keep your heating on 24 hours at 16 degrees. But does that heat up the room to more than that, is it somehow cumulative, as 16 degrees sounds bloody chilly to me?