Hello! It has been years since I had physics at uni, and I have forgotten lots of it, so I need some help here. The issue concerns the underfloor heating pipes and how to reduce loss. Most conventional systems use insulation boards to slow down heat conduction towards the floor. Some extra slim systems disregard conduction and focus on heat radiation: they use aluminum foil under the pipes to reflect the IR radiation away from the floor. Rarely are the two combined. I can't help wondering: will I lose more heat through radiation, hence I need the reflective foil, or will I lose more heat through conduction, hence I need the insulation board, or do I need both? Thanks for your advice.