"Aesthetics and eco-building don't always go hand in hand, but they do in the case of underfloor heating. On the eco front, the water circulating in the coiled pipes below the floor doesn't need to be very hot (only 45-50C, as opposed to 80C in radiators), and can easily be supplied by alternative heat sources such as solar panels, a ground-source heat pump or a wood-burning stove." (Quoted from article)