The Romans are credited with the invention of the first underfloor heating system

 
 

The closest thing to central heating today was the hypocaust system, a heating system used during the Roman Empire which distributed the heat from an underground fire throughout a space beneath the floor. Hypocausts were vital to the ancient Roman system of central heating, and according to some historians, it was the first underfloor heating technology in human history.

Considered as one of the Roman civilisation´s greatest achievements  Photo Credit

 

Caldarium from the Roman Baths at Bath, in Britain. The floor has been removed to reveal the empty spaces through which the hot air would flow   Photo Credit

 

To keep air flowing, a system of flues were constructed into the walls  Photo Credit

 

Wall flues for hot air circulation   Photo Credit

 

The floor was raised above the ground by pillars, called pilae, made of brick, mortar or concrete, usually about two feet high so that hot air could circulate under it. A furnace composed of a continuously burning fire would be built under one corner of the room, so the hot air would circulate under the floor and inside flues built into the walls and warm the room.

This air can warm the upper floors as well. It required slave labor to fuel, monitor, and clean the furnace during the day. Of course, it was not sophisticated as today’s modern underfloor heating systems but, technologically, it was very advanced in that period.

The main use for hypocausts was found in the large public bathhouses  Photo Credit

 

The hypocaust of the Western Bathhouse built in the 4th century AD, Scythopolis (Beth-She’an), Israel    Photo Credit

 

The hypocaust of the Great Baths complex, Ancient Dion   Photo Credit

 

Hypocaust from a luxury residence, the floor was supported by pillars of round terracotta blocks, Gallo-Roman Museum of Tongeren, Belgium    Photo Credit

 

Ruins of the hypocaust under the floor of a Roman villa at La Olmeda, Province of Palencia (Castile and León, Spain)   Photo Credit

 

Hypocaust under the floor in a Roman villa in Vieux-la-Romaine, near Caen, France  Photo Credit

This system was usually used for heating public bath houses and only the wealthier Romans could afford to have such a system in their residences. With he decline of the Roman Empire, most public baths fell into disrepair, and the hypocaust was disused.

Read another story from us: The famous ‘Capitoline Wolf’ symbol of the Roman Empire was made in the middle ages

However, the heating system continued to be built and used in the Early Middles Ages and was adopted for the heating of the hammams, an Islamic variant of the Roman baths.