They were also built to strict specifications, so that their ‘hypocaust heating’ would work properly. This system used water, heated in fiery furnaces under the raised floors of the baths.

Students could equip their model with a hypocaust too, placing a floor over stacks of plastic bricks to create a cavity. The hotter the bath, the larger the hot-air cavity beneath its floor.

Image caption, Some Roman homes were kept warm with an underfloor heating system called a 'hypocaust'. The floor was raised up by piles of tiles or stone pillars to allow warm air to circulate.

where visitors can view the preserved hypocaust - a Roman underfloor heating system - and a mosaic floor. Verulamium Museum, a 2024 Tripadvisor Traveller's Choice winner, brings the city's Roman ...