Cutaway diagram of a Roman hypocaust system (underground heating).
Drawn by David Dobson © Canterbury Archaeological Trust Ltd
Hypocaust
From Wikipedia, the free encyclopedia
Caldarium from the Roman Baths at Bath, England. The floor has been removed to reveal
the empty spaces which the hot air would flow through.
Ruins of the hypocaust under the floor of a Roman villa.
A hypocaust is an ancient Roman system of central heating. The word literally means
"heat from below", from the Greek hypo meaning below or underneath, and kaiein, to
burn or light a fire.
It is traditionally considered to be invented by Sergius Orata (although it is not fully
confirmed), who devised this ingenious system for heating public baths and private
houses. The floor was raised off the ground by pillars and spaces were left inside the
walls so that hot air from a furnace (praefurnium) could circulate through these open
areas. Rooms requiring the most heat were placed closest to the furnace, whose heat
could be increased by adding more wood.