Radiant floor heating (left side image) is different in that it doesn't rely on moving the air into a space to heat that space. Radiant floor heating uses a fluid filled tube system and places it in the concrete under your feet and heating that fluid heats the surface under your feet thus radiating the heat upwards. This keeps more of the heat where the people are located. The amount of energy is greatly reduced only having to move small amounts of fluid thru the floor as compared to large amounts of air.