The importance of reliable climatic data in the energy evaluation

In the last few years, more and more attention has been focused on energy issues, as it is pointed out, for example, by the Directive 2002/91/EC on the Energy Performance of Buildings and Directive 2009/28/EC on the promotion of the use of energy from renewable sources. However, in order to do that, reliable tools for technicians to design systems for such topics should be provided. Nowadays, several software are available; the weak point is the availability of reliable climatic data and, above all, the ones referring to solar radiation.