Slaves were used to burn fuel to keep the baths hot under the floor.
The Roman bathhouses were heated by the hypocaust system. The heat would rise up from pipes under the floor into the water or the rooms.
They made the houses themselves and sold them among each other somewhat like we do now.asfddwasvncnwhakembcvaVADNCJHDJSBGVCASDHB VCambcb
TYhe wealthy Romans lived in a domus in the city and a villa if they were in the country.
The compluvium was a hole in the roof over the atrium where the rain fell through, into the impluvium.