Beyond cultural and historic values, sustainability as a new kind of value for historic buildings

In attempts to improve the energy efficiency of protected historical buildings, two barriers arise. The first is the restrictions imposed by authorities that are responsible for cultural heritage preservation. The second is the exclusion of protected buildings from strict compliance with energy efficiency requirements in current regulations, such as the issue of an Energy Performance Certificate, which removes them from conventional channels of public policies. Both of these issues put heritage in a delicate situation, especially when they are intended for privately developed residential uses. This paper presents a methodology for assessing and establishing a trade-off between energy performance and the cultural value of heritage buildings through the comprehensive analysis of a case study: the retrofitting of Can Armengol Palace in Palma de Mallorca (Spain). The study revealed (1) the need to objectify the cultural values of the building as far as possible to identify conflicts with the strategies of energy efficiency improvement; and (2) the appropriateness of considering every aspect of a rehabilitation intervention in a global simultaneous approach, not just energy aspects. The method that was used had five steps: acquiring a deep knowledge of the building configuration, assessing the building performance for every legal requirement, identifying cultural values, defining intervention criteria, and analyzing intervention effects on the protected elements of the building. The most important contribution in this study is the detailed and extended definition of architectural heritage values and the consideration of interventions resulting from sustainability retrofits as a new kind of value, that reflects current worries, for which future generations will remember us.Postprint (author's final draft