The earliest known record of an underfloor heating system was in ancient Rome. The Romans built this heating system called hypocaust for heat distribution. It was the forerunner of the present day heating systems and ahead of its time.
The Hypocaust system of the Romans worked using the principle of heated hot air which was generated by burning fires.
A system of hollow chambers was constructed between the ground and the bottom of the rooms to be heated. Hot air that rose from the fires would flow through these chambers and heat up the rooms above.
The source of heat was a furnace that stood at one end of the room. Hot air generated from the furnace would be used for heating up by flowing through the spaces between the ground and the room floor.
Hypocaust Systems were also built inside walls of buildings, and followed the same principle of heating with hot air to keep the walls warm.
Hypocaust systems weren’t accessible to all, only the wealthy as servants were needed to stoke the furnace and keep the fires burning. Besides, the building value would also rise if it came with a hypocaust system in place.
The boiler heats water and this hot water flows through pipes installed under the floor, thereby heating up the floor.
The pipes run across the length and breadth of the floor in a manner that ensure even distribution of heat.