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About Radiant Heat

The History of Radiant Heat

Although we tend to think of radiant heat as a fairly new concept, radiant floor heating technology has been around for thousands of years. The materials and technology have changed, but the efficient principle behind radiant heat has remained constant.

Radiant heated tile floor. Evidence has been uncovered to reveal that radiant heating was in use as early as 10,000-5,000 BC in China. Ancient people used radiant heat to warm their beds and floors. Inhabitants drafted smoke from fires through stone covered trenches in the floors of their subterranean dwellings. The hot air heated the floor stones, and radiated into their living spaces to give them warmth. Evidence of radiant heated floors based on this principle was found recently.

In 500 B.C., the Greeks, and later the Romans, developed the "hypocaust", which featured a more efficient and less evasive process. The hypocaust utilized pillars that raised the floors to create a space underneath where hot air could circulate. Spaces were also left inside the walls of their structures so that hot air and smoke from the furnace would pass through enclosed areas under the floor and in the walls before rising out of flues in the roof. A furnace was usually located against the outside wall of the structure where a worker would be responsible for feeding the fire.

Water was also heated and circulated under floors, marking the first hydronic floor heating systems. While the hypocaust marked a significant advancement in radiant under floor heating, the process of heating itself was labor-intensive and high in fuel costs, which made it a luxury for those living in villas, and at the public baths. Today’s hydronic systems feature specially treated water that is heated by a boiler and then pumped through a series of PEX tubing that is embedded in the floor.

The Technology Behind Radiant Heat

Radiant heating cable shown under tile floor and thinset. Radiant heat involves the transfer of energy that radiates heat outward from its source. Today's radiant floor heating systems utilize a heating element (either electric heat cable or PEX tubing for hydronic systems) to heat the floor. The heated floor radiates warmth to objects in contact with it, and ultimately warms the air in the room.

Unlike forced air heating systems that blow warm air through vents, and rises quickly to gather near the ceiling, radiant heat originates at our feet, and slowly rises to warm the room. This provides a luxurious warmth and comfort that must be experienced to be fully appreciated.

In addition to the comfort, another popular benefit of radiant heat systems that homeowners enjoy is that unlike forced air systems, radiant heat systems warm the home without stirring up dust and allergens. Electric radiant heating systems also operate silently and are virtually maintenance free.