Messina's historical heritage rebuilding after the earthquake of 1908 was almost exclusively directed both to ensure the static safety of structures and casings and giving new dignity through a rich aesthetic language and preserving the historical identity of the urban fabric. This approach did not keep into account all the buildings energetic response and the optimization of occupants comfort. From here, the need to prepare swift and exhaustive methodology of analysis of the building performance level both in terms of conservative asset than energy performance. Once you have identified the overall criticalities through the monitoring campaign, the scenery is enriched by data derived from indoor comfort perception, obtained by administering an appropriate survey. In this paper it was analyzed the Palazzo dei Leoni's energy vulnerability, the current seat of the Province of Messina, subject of reconstruction in 1914 after the earthquake and chosen as a case study. The validity of the suggested screening methodology lies in potential applicability to any fine building , subject to postconflict or post-seismic, needing an energy retrofit, supported by a preliminary investigation of the building's potential decays performance and of the level of indoor comfort.