Università degli Studi di Bergamo Sustainable renovation of historical buildings in the Upper City Bergamo is one of the most important industrial city in the North of Italy but it is also a very attractive place for tourist from all over the world, due to the proximity with Milan and its own historical heritage, characterized by ancient monuments, churches and in particular the upper part of the city, named Città Alta. The upper city, surrounded by Venetian walls built in the 17th century, forms the historic centre of Bergamo and it has numerous places of cultural interest such as the Old Square, the Cathedral and the San Vigilio Castle. Città Alta is not only an historical site, it is also one of the most exclusive residential area in Bergamo, in fact almost 3100 persons live in the upper city and there are also some shops, boutiques, pubs and restaurants. Città alta is an extremely expensive place to live and almost all the residential properties are developed in ancient buildings. This last aspect lead to a relevant problem area, that involves not only Bergamo, but a lot of Italian cities: the need of the sustainable renovation of historical buildings. Over the last 50 years In Italy the majority of the renovations of ancient buildings have been focused on architectural and structural aspects, while nowadays we believe that, due to the diffused environmental issues, focusing on sustainability of building is a key objective for a smart city. The aim is to reduce the negative environmental impact of ancient buildings, in order to reduce emissions and save energy, trying to manage the dichotomy new way of building and historical heritage. In this context the challenge is to adapt the new solutions of green energy to the ancient buildings without ruining their peculiarities in terms of architecture and design. This problem is also related to the search of customize alternative solutions. The data from the SEAP 2010 (Sustainable Energy Action Plan ) demonstrate that the residential buildings in the upper city have one of the highest value of carbon dioxide emissions per person equal to 8.28. 1 Università degli Studi di Bergamo In addition in Città Alta the majority of the houses and buildings used for commercial activities have the lowest levels of energy certification (F and G). The energy certification is a procedure of evaluation established by the European Community in 2002 that helps to classify the level of consumed energy by a building. The highest performance is classified with A, while the lowest with G. The energy class is determined considering the level of kWh/(m2a). The City of Bergamo has already developed a series of strategies for energy conservation in the construction sector and the objective of SEAP is to reduce the emissions of carbon dioxide of 20% by 2020. The problem is that these activities are focused mainly on the procedures for the construction of new buildings. Nowadays a clear plan for the sustainable renovation of ancient residential buildings in the upper city does not exist, also because the authorities are not able to provide funds to implement it. Concerning other historical buildings such as churches (the cathedral), Castles, museums, they are a relevant part of Bergamo cultural heritage. However, if these buildings are normally heated, they cause relatively high energy consumption. 2 Università degli Studi di Bergamo Without appropriate solutions, there will always be a conflict between preservation and energy conservation measures. Energy measures which are usually used for new buildings are often aesthetically not satisfying. Besides that they are also difficult to apply and risky. An interesting solution (solar panels technology) has been developed in Città del Vaticano (Rome), where a photovoltaic system with 2400 solar panels has been installed on the roof of Aula Nervi in 2011. In conclusion in order to solve this problem area, the following questions should guide the search for a proper solution: How can (historic) buildings be conserved and enhanced through energy-efficient measures? Which strategies can be taken to adapt (historic) buildings to new functions and user demands? Which options realize an optimum building quality with the least possible intervention? 3