Today, the building sector alone accounts for 40% of the total energy consumption in the European Union (EU). In most EU member states, about 70-90% of the buildings were constructed at least 20 years ago. Due to this, these buildings have a worse energy efficiency behavior than the new ones that comply with current regulations. As a consequence, acting on the existing building stock is needed, developing special methods on assessment and advice in order to reduce the total energy consumption. This article addresses a procedure allowing the classification and characterization of existing buildings facades. It can help researchers to achieve in-depth knowledge of the facades construction and therefore knowing their thermal behavior. Once knowing that, the most appropriate upgrading strategies can be established with the purpose of reducing the energy demand. Furthermore, the classified facade typologies have been verified, complying with current and future Spanish regulations and according to the results obtained, a series of upgrading strategies based on the opaque part and those in the translucent part, have been proposed. As a conclusion, this procedure helps us to select the most appropriate improvement measures for each type of facade in order to comply with current and future Spanish regulations. This proposed method has been tested in a specific neighborhood of Madrid, in a selected period of time, between 1950 and 1980, but it could be applicable to any other city. (C) 2014 Elsevier B.V. All rights reserved.