- The Hypocaust was the Roman central heating system used in the Roman Baths and in the Roman Villas.
- A good example of a Roman Hypocaust lies under a mosaic in the Park at St. Albans, next to the St. Albans Museum.
Heating the Roman Villa
- The Hypocaust:
- The floors of the Roman Villas were raised on pillars.
- The Walls:
- Hot air rose up through pottery pipes placed against the walls.
- Praefurnium:
- Hot air was supplied from a wood burning Furnace called the Praefurnium.
- Hot air from the Praefurnium was then allowed to circulate underneath the floors
Heating the Roman Baths
- The Hypocaust:
- The floors were raised on pillars, to allow the hot air to circulate underneath them.
- The Walls:
- These had hollow flues through which hot air rose up from below.
- The Praefurnium or Furnace:
- This was kept burning by Slaves. The Calderium was above the Furnace making it the hottest room.
- Hot air then circulated under the Hypocausts and up the walls of the Tepidarium, and then the Frigidarium, which was the coolest room because it was the farthest away.
Hypocaust and Roman Mosaic in St. Albans Park