Cost optimal analysis of energy refurbishment actions depending on the local climate and its variations

The cost optimal methodology indicated by the European Directive 2010/31/UE represents the starting point to support decisions for refurbishment interventions. The procedure is much more useful if considering the limited available investments from Public Authorities or privates and represents an important decision tool to define the owners' constraints and the economic commitment in the years. However, the results are usually affected by the influence of some variables, among which there are the climatic conditions, subject of the present investigation. To quantify some effects, the best costs/benefits ratio is evaluated among some improvement scenarios built on a series of energy efficiency measures, in the climatic conditions of some locations. The first set of calculations compares energy performance and global costs referring to climatic data taken from the Italian National Standard UNI 10349 edition 1994 and 2016. The second analysis is performed, for one location, on the basis of the two reference climatic datasets and the registered climatic data of the last 20 years. From the results analysis, it can be observed the need of indications by the European Commission on a regularly reference climatic data updating, to guarantee in all the countries affordable calculations for the cost optimal refurbishment solutions, and on the introduction of a tolerance/confidence range to take into account the real climate variations.