Infrared heaters are considered more energy efficient in comparison to central heating system and convection type heaters. Convective heaters require a higher heat load to get the air in the room to a certain temperature, so the energy requirements are higher. So convection heaters require higher capacity.
Convection heating has warm air mixing with cold air, and this causes infiltration losses. Consequently, this significantly affects energy use and comfort level. Infrared heaters heat only the objects, and as the objects retain the heat longer than the air they keep the warmth for a longer period of time. At the same time they emit the warmth for a longer time, so as a result they use less energy.