Radiators only radiate 20% of the heat they produce, the remaining 80% is convected up to the ceiling or escapes through a near by window. Radiator reflector foils, such as the Radflek, reflect the heat that radiates from the back of the radiator, back into the room, preventing it from being absorbed by the wall. The Radfan, however, redirects the 80% of heat that is lost via convection blows it out into the room.
Does what it says on the advert, gently blows the heat from your radiator into the room. There is a slight background noise from the fans, but not distracting