The Boiler Room still houses the ancient boiler which originally supplied the steam power necessary to drive the machinery used in the Campolmi textile mill.

The first steam boiler installed in the Campolmi textile mill - in 1892, just a few years prior to the construction of the brick chimney which can still be seen in the courtyard - was composed of two Nivilli Cornovaglia boilers, although these were replaced in 1925 by the Breda Humbdolt system (modified in the 1950s in order to enable the use of fuel oil) which still occupies the boiler room.

Despite the fact that only part of the original boiler is still visible, it nevertheless enables visitors to appreciate the complexities involved in distributing power throughout the textile mill during the early years of industrialization, reminding us also that the building in which Prato Textile Museum is housed was once the place of work of a large percentage of the population of Prato.