Hypocaust

From ZuluNotes - Free Leaving Cert Notes

The Roman Baths used the Hypocaust system for heating the building and the pools. This underfloor heating system had hot air heated from the basement fires flowing between the brick or concrete columns which support the ground floor. The the warm air flowed through wall ducts into the rooms at the baths and quickly heated them. In some baths the floors would be so hot that the bathers would have to wear wooden sandels to stop their feet from being burnt. The fires in the basement where stocked by slaves of the baths.