Radiant heating is the transfer of heat energy using energy waves. Heat energy in the form of radiation will always travel from a hot surface to a cooler surface. Consider the Sun, the Earth’s only source of heat, which is 150 million Km away. The Sun warms the Earth from a fantastic distance purely using radiant energy. Even before the air is warm, heat from the sun can be felt, such on a clear winter morning, or on top of a snowy mountain. Warmth from the sun is instantaneous – you experience this when the sun emerges from behind a cloud.