Whilst cities cover only three percentage of Europe's surface, they account for eighty percent of the buildings and seventy five percent of carbon dioxide emissions. Therefore one of the major challenges faced by European countries today is the reduction of CO2 emissions that contribute to climate change. This is particularly true for cities as they account for eighty percent of the buildings and seventy five percent of carbon dioxide emissions. Buildings, whether commercial, residential, private or social housing, account for almost fifty per cent of energy use, with consequent impact on climate change and  CO2 emissions. They are therefore an obvious area where efforts have to be concentrated as improvements in their energy efficiency can deliver substantial gains in the fight against climate change.  All European countries are facing the same challenge to improve energy efficiency and reducing CO2 emissions, therefore a coordinated and transnational approach is needed in order to introduce coherent policies and achievable targets that can be met by all countries. The implementation of strategies in EnerCity for the reduction of energy consumption and the consequent increase of energy efficiency in buildings stocks and urban agglomerates will therefore contribute in an effective and direct way to the achievement of the fight against climate change. Achievements: EnergyCity project aims at contributing to the reduction of energy consumption and CO2 emissions of cities through measuring the heat loss of urban buildings by aerial thermography. In the first year partners have collected information on the state of the art of thermo-mapping and on previous achievements, results and similar projects. In the second and the third year our focus turned to aerial data acquisition, data processing and software development. Three on-line web-tools have been carried out so far. The Data Catalogue collects existing technical information about current knowledge of remote sensing and urban energy and it is recommended for professionals. The Knowledge and Information Base Repository is prepared for general users, particularly municipalities. It contains a collection of information of similar projects and policies. The two modules are supported by the Glossary to identify energy efficiency and performance terminology used in partner countries and provides common definitions and clarification. The webtools are already available on the web page www.energycity2013.eu/results. The project involves flight missions in 7 pilot areas of Europe (Munich, Bologna, Prague, Velenje, Budapest, Ludwigsburg and Treviso). The thermal flights surveys have been completed in all cities, the hyperspectral flight surveys have been done in 6 cities. Bologna was an exception, here the hyperspectral aquisition was substituted by satellite data. The data process is is almost finished, only some minor corrections are left for Budapest and Prague. The third webtool, probably the most important project output, the spatial decision support (SDSS) system has been developed and is already available on the project's website. The SDSS system is an online geographic information system where users can achieve energy and CO2-emission related information about the building stock inside the user-selected area on the digital map. The tool is password protected, but access can be obtain upon e-mail request. 7 test areas can be analysed in the tool: energy consumption, CO2 emission can be estimated in the Home Energy Analysis module for a user selected area. In addition, the influence of modifying the heat source can be determined. In the next six months our focus will be on the application possibilities of the SDSS and there will be a project review&closing phase. The participating cities will demonstrate how to use the tool for energy loss and CO2 emission assessment, fuel poverty analysis and policy support.