Radflek is an energy saving radiator reflector. The manufacturer claims that it reflects 95% of the wasted heat energy radiated from the rear of a radiator back into a room. Radflek is described as a laminated aluminium foil with a long lasting coating that prevents oxidation and preserves its high reflectivity. Hence with Radflek fitted you should use less energy to heat rooms and so energy bills will be less. See full report here.