What is the primary principle behind radiant heating systems?

The primary principle behind radiant heating systems is that radiant energy travels through air without heating it. This means that the system heats surfaces—such as floors, walls, or ceilings—which then transfer warmth to the people and objects in the room. Unlike convection heating systems that heat the air first, radiant heating relies on infrared radiation to transfer heat directly through space. This results in a more even and comfortable heat distribution, as the surfaces absorb and then radiate the heat to their surroundings.

In radiant systems, the efficiency is enhanced because there is less heat loss to the moving air and greater comfort is achieved as individuals feel the warmth directly. Thus, option B accurately captures the fundamental principle behind how radiant heating operates.