With radiant heating appliances we employ the radiant principle to directly heat objects, surfaces and people rather than having to warm the air first. This prevents wasteful heat stratification associated with convection of warm air, typical of traditional heating systems. Many people expect heat to rise, but in fact it’s only warm air that rises because warm air is lighter than cold air. Warming the air creates a convection current with hot air rising to the top of the room. The rising warm air is replaced by cold air and this creates a convection flow. With convection heating, such as traditional wall mounted radiators, much of the heat is lost to the unoccupied upper space of a room – this is a real problem in rooms with high ceilings or pitched roofs. In fact, the air temperature may increase as much as 3°C for each vertical metre in a room. And of course, if warm air is lost through opening windows or doors, more energy is required to reheat incoming cool air. However, ILO Design Radiant Heating appliances emit up to 75% of their heat output in the form of radiated heat. Thus, convection is reduced and most of the heat is then radiated directly to the occupants.