Dose of History: The Hypocaust

By Alexandra Wenger ‘21


In case you haven’t stepped outside lately, it’s been pretty cold. At the end of January, a polar vortex hit the New York City area with below-freezing temperatures that made everyone grateful for indoor heating. But to whom do we owe our gratitude? It turns out, we owe it to the ancient Romans. The hypocaust, an invention that can be dated back either to the temple of Ephesus in 350 BC or inventor Sergius Orata in 80 BC, was the forerunner for modern central heating. Though its origins can be traced to Rome, hypocaust ruins have been found throughout all of Europe, including England, Italy, Spain, Germany and Africa.

This invention consisted of a space beneath the floor of a room that needed to be heated, such as hot baths or other public buildings. This space would be held up by pillars called pilae stacks, which supported not only the tiles and concrete roof of the hypocaust but also the flooring of the room above. A furnace would produce smoke and hot air, which would circulate through the space and heat the room above it. Therefore, rooms that the Romans wanted to be kept the warmest were nearest to the hypocaust. However, the smoke would also make its way up through clay pipes in the walls that led to the roof, heating the adjacent rooms as it went.

Though expensive and rarely used in common homes, the hypocaust was the world’s first glimpse into the wonders of indoor heating. So next time you feel thankful for your space heater, remember its ancestor the hypocaust and its impact on centralized heating.

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