The infrared heating exploits the principle of irradiation and that is the transfer of energy (therefore heat) by means of electromagnetic waves. There is no need for contact between the hot and cold elements because electromagnetic waves also travel in a vacuum, like the Sun which heats and illuminates the Earth from 150 million kilometers. Or as it happens in the high mountains in winter, when on clear days you can sunbathe in your bathing suit even if the air is freezing.
That said, when can a infrared heating? Apart from the outdoor tables of the bars in winter, the heating by radiation it is the only convenient one in environments where it would be too expensive to heat the air, that is, large ones: churches, gyms, warehouses, hangars ... Or where you need to heat only some areas, which can be done by placing the infrared diffusers with radiant panels in precise points. It is the only effective system in the presence of large heat losses and outdoors.
The infrared heating by radiation it is normally carried out from above with incandescent emitters powered by gas (methane or LPG) or electricity (halogen or quartz diffusers) positioned on the ceiling, trusses, floor lamps and chandeliers. These are systems without thermal inertia that heat up immediately upon switching on and for this reason they are particularly suitable for use for short periods as in the case of religious functions and sporting events. At home, an infrared diffuser can be useful in a room to be heated quickly only when needed, or near the sofa in the evening to watch TV with the home system at a minimum.
The choice of the type of system of infrared heating depends on the availability and on-site cost of the fuel, the installation height of the radiant panels and the size of the room to be heated. Other factors to consider are the ventilation of the premises, especially important in the case of gas systems and the frequency of use. An advantage of these systems is that they do not require masonry other than the holes for the passage of pipes and cables, so architectural constraints are not a problem.