The European Community SAVE Directive 76/93, makes mandatory, among other things, for member states to implement an action called Energy Labelling of buildings. This labelling should consist of a description of the energy characteristics and some information about energy efficiency; and is aimed at reducing CO2 emission by means of a parallel reduction in energy consumption. The European Union allows each country to adopt the most suitable methodology according to weather and building industry characteristics and socio-economic context. The Ministries of Public Works and Industry, the latter through the Spanish National Energy Agency (IDEA) are responsible for carrying out the directive. The work has been developed in two phases, the first being Energy labelling in Officially Protected Dwellings (CEV). CALENER program is the second phase and it includes all kind of buildings.