In Italy many museums are located in historical buildings, converted later to this functionality. The insertion of energy systems, for fruition and conservation's needs, happened fairly recently with low attention to environmental sustainability and energy efficiency. "Energy and Buildings" is essential in EU Community Policies aimed at reducing greenhouse gas emissions, at limiting fuel consumption and at encouraging the use of renewable energy sources. The museum buildings can play an important role in this scenario; they should be retrofitted seeking to balance the "passive" energy performance of the building-envelope and the "active" one of the systems. However there are only few cases where energy retrofit have been carried out and few data related to energy consumption and effects after retrofitting. Fondazione Musei Senesi with Politecnico di Torino have matched these aspects in the research project "The Museum building; Energy, Systems, Safety & Security", aimed at exploring the performance of the whole building envelope and systems for the indoor climate control, with particular attention to energy. The study was carried out on 43 museums using specific tools developed ad hoc (self-assessment checklist and a handbook). The project can be a point of reference for different museums widespread throughout the Italian and European territory (C) 2014 Elsevier B.V. All rights reserved.