These models are suitable for the heating of people in houses, workshops or offices. They are fitted with ceramic long-wave infrared elements. They do not emit any visible light and have a very high efficiency. They do not heat the air and so are ideally suited to places which are difficult to heat, such as buildings which are badly insulated, are draughty, or have high ceilings. These appliances must be fixed to a ceiling or to a wall at a minimum height of 1.9 meters.