**Elena Mazzola, Tiziano Dalla Mora \*, Fabio Peron and Piercarlo Romagnoni**

Department of Architecture and Arts, IUAV University of Venice, Dorsoduro 2206, 30123 Venice, Italy; elenoire\_me@libero.it (E.M.); fperon@iuav.it (F.P.); pierca@iuav.it (P.R.)

**\*** Correspondence: tdallamora@iuav.it

Received: 6 August 2019; Accepted: 15 October 2019; Published: 17 October 2019

**Abstract:** The valorization and sustainable management of historic centers is a topic relevant to the cultural identity and heritage of European cities. A rational strategy to preserve the centers must consider both energy and environmental retrofitting, even if this is a complex issue requiring interdisciplinary approaches, dedicated diagnostic procedures, and specific tools. Within this context, this paper proposes an integrated method for energy and environmental analysis specifically devoted to historical building retrofit. Attention is focused on cases in which building management is not interested in renovation or in a deep conservation project, but instead in green management and maintenance overhaul. The basis of the procedure is the Leadership in Energy and Environmental Design for Existing Buildings: Operations and Maintenance (LEED O+M) rating protocol. The global goal was the definition of an intervention strategy indicating the principal direction of action. The first step is identifying critical issues in the operation of the building through energy diagnosis and dynamic thermophysical simulations. The second step is defining a panel of appropriate retrofit measures. The third step is choosing between alternatives to increase the sustainability performance following an environmental assessment scheme. Ca' Rezzonico in Venice (Italy), a 17th-century palace, nowadays the seat of a museum, was used as a case study to apply the proposed methodology.

**Keywords:** energy audit; green buildings; LEED rating system; operation and management; methodology; workflow; historic buildings
