The EU-GUGLE project mobilises public / private resources to build showcases of totally around 226,000 m2 of cost-efficient urban Zero Carbon Building Renovation models in AT, FI, DE, IT, SK & ES - together with associated cities in SE&TR. EU-GUGLE is designed to respond to the needs of an effective take-off of the Smart City initiative within the EU SET-plan and in particular by demonstrating different sustainable energy technologies and techniques integrated in an intelligent way within lighthouse buildings. Although the individual demonstration projects are independent from each other, being designed to fulfil local building-user needs and utilising local resources perfectly integrated in these smart objects, there are many similarities between them.The foreseen implementation plan is a symbiosis of integrating activities, such as ● Sharing latest research results especially of retrofitting technologies & smart RES integration into buildings ● Demonstrating appropriate energy solutions in order to reach energy savings of 25.6 GWh/a for heating and DHW and 2.5 GWh/a for electricity in terms of primary energy ● Establishing adequate business environment favourable for Smart City demonstrations ● Serving as benchmark for sustainable buildings&districts and spreading best-practice ● Implementing innovative retrofitting technologies & techniques validated in six partner cities ● Developing a transparent EU-GUGLE model for immediate replication in three associated cities and abroad. ● Connecting social needs of building-users with innovative market actors.By deploying an interdisciplinary approach, an innovative / cost-efficient mix of actions, a set of sustainability oriented solutions will be pointed out and transferred to and among the identified target groups of EU-GUGLE. The outcomes and related benefits will be fully exploited by an effective range of actions generating local activities with high visibility character together with the major stakeholders.