The “calidarium” consists of three spaces characterized by walls covered with tubules for heating, elegantly covered by marble slabs. The entrance is through doors equipped with oblique jambs, a clever detail to counteract heat loss. The first room, rectangular in shape, has two opposite apses along the short sides. The floor houses a fascinating geometric mosaic, alternating squares, crosses and hexagons elongated dark shades on a light background. The second room, square in shape, has two marble-lined and heated tubs. The floor is distinguished by a rich polychrome mosaic that includes a suggestive central rose window. The third room has an octagonal shape, and despite the damaged floor, retains a polychrome mosaic with a fascinating pattern of circles intertwined with stylized flowers, topped by a cocciopesto flooring (earthenware flooring).