In a new build bungalow (NE Scotland) which has underfloor (concrete) heating. It's on 24/7, set at 22deg, apart from bedrooms, which are lower. Over the summer, no heating was called for, as the house is very well insulated and sat between 23 and 26 degrees, depending on the amount of sunshine. It lost very little heat overnight. I noticed about ten days ago that the hall floor was warm. That seems to be keeping the temp up to 22 in the rest of the house without any other floors asking for heat. Interestingly, in the winter, the bathrooms and bedrooms stay within set temp due to the heat from the hall, so the floors aren't 'asked' for heat, so stay cold. If we turn up the thermostat, the floors will heat, but this brings the temp up to an unnecessary 24 degrees plus. We understand this set up now, but guests still expect the floors to be warm because of the term 'underfloor'. I am sitting in an open plan lounge/diner/kitchen (30 X 16 feet) right now with the temp at 24 degrees. It started off at 22 in the morning, reached 23 due to the sun, then 24 as the oven was on at tea time. It will remain at 24 till after midnight, without this floor having come on at all yet since May. The main downside is that's less controllable than radiators, in that switching it completely off or on isn't as 'instant', but on the whole it's great.