The main goal of the Project LIFE, New4Old Project ( LIFE10 ENV / ES / 439) financed by the European Commission, is to define the best methodology and practices available for the refurbishment of social housing with energy sustainable criteria and also implement innovative technology to combat Climate Change trough an efficient use of resources and energy. The institutions that participate in the project are the Technological Center AITEMIN, the University of Madrid (UPM), the Technological Center of Ceramics and Glass of Portugal (CTCV) and the Municipal Housing Society (SMZV). The demonstrative project consists on an energy refurbishment of two buildings with social housing for rent located in the historical Center of Zaragoza, according to the conclusions and strategies developed in the LIFE project. When is decide intervening in houses with this features, the passive strategies become essential since the tenants have limited incomes and frequently can’t afford paying the energy. Therefore the proposed action improves the passive behavior of the building and achieves a thermal comfort, with out increasing the financial costs related to energy consumption.