Infrared heater bulbs conduct heat via electromagnetic radiation that transfers heat energy from one body to the other, according to Technilamp. For the heat to be transferred, no contact between the two bodies is required. Infrared heating thus occurs both in atmosphere and vacuum, explains Wikipedia.
As in all heating processes, infrared heater bulbs conduct heat by transferring it from a body that has a higher temperature to one that is at a lower temperature.The heat generated by infrared light bulbs is a product of the infrared radiation or light generated by the heating filaments encased in the bulb. When the cooler body absorbs energy in the form of infrared light, it also gets warmed in the process. However, since air does not absorb infrared radiation, the environment around the body will not get heated.
The efficiency of heat conduction by infrared bulbs is usually up to 86%. This implies that the heaters can convert a maximum of 86% of the electrical energy that they use as radiant heat. The heat produced is instant, and heat conduction by infrared heater bulbs is extremely focused because only the body within the field of radiation is heated. This makes the infrared heater bulbs particularly efficient and economical heat conductors.