Hi everyone! Based in the East Midlands and starting the journey to our dream house, we are at the planning application stage. We want it to be thermally efficient and use renewable energy where possible. We are going for a high insulation spec, and air source heat pump with underfloor heating plus solar panels. The architect has encouraged us to have porcelain, stone, concrete or timber flooring (not LVT) to allow the materials of the building to use the thermal mass more effectively. My concern is, I've just read an article about ASHP which states that they are prone to failure/inefficiency in the depths of winter because they have to work so hard when its really cold, and that you should have a back up heat source such as gas or biofuel boiler. This seems to defeat the aims. Anyone out there any experience of living in a house with ASHP and underfloor heating?