Which is the task of the historic built environment within the development of a Smart City?

The European energy policy set the objective of reduction of 20% of energy demand and CO2 emission by 2020 and the building sector is at the centre of European interest. In fact the new initiative Smart City supports cities towards a 40% reduction of greenhouse gases emissions by 2020 through pioneering measures for buildings, energy grids and transportation. To which extents historic urban areas are included in these targets? The paper analyses several energy retrofit actions undertaken by European cities, to define a system of cultural values and local policies useful to public administrations for managing an acceptable adaptation of heritage architecture to new sustainability requirements of Smart Cities.