The CO2 emission is the main cause of the greenhouse effect, a major challenge for the future will be the saving of CO2 worldwide. This objective is not only a national but rather a global, only a cooperation of European countries can achieve this goal within Europe. Great share of energy consumption have the fossil fuels in the private living area. This project is concerned with aspects of how to save energy through improvements in existing buildings, replace sustainable fossil fuels, and thus Europe can save CO2. In this project, the participants have to deal with the technology in the field of renewable energy, insulation, as well as its ecological compatibility with the environment. These papers will be elaborated on this topic by the participants on the first project meeting. It must be specifically addressed to the climatic and geographical conditions of the countries involved, as in Norway are very different climatic conditions than in Greece. By way of example, three different regions in Europe are discussed in this project, a northern, southern and central region. A house is selected in Volos for the southern part of Europe and a house in Norway for the northern area. At the school in Bersenbrück a former caretaker's house is selected, which is near the school and to be renovated in the near future. This example is for the central region in Europe. The participants have to deal with how you can reduce through energy-saving measures for these homes energy consumption , so that the standard of the German KfW bank will reach the level KfW 55, possibly zero energy buildings can perhaps even generate additional energy itself . To this end, the participants have to deal with the technology of renewable energy and insulation of residential buildings. It is important that they pay attention to the specific climatic and geographical conditions of the different regions in Europe. Thus, for example, in the southern areas in the summer to cool the houses and in the northern areas in winters a good thermal insulation is important. When energy is available in the different regions also have different conditions. Thus, for example, in the southern areas the sun is the most important supplier of energy, geothermal energy in Hungary and Norway, hydropower. Each participant will bring a key issue in the project. This issue is all the users must specify at the beginning of the project. It will be presented at the project meetings in the countries concerned in each case. The overall objective of this project is to achieve a different kind of thinking and action among the participants in terms of the increase in CO2 load in the atmosphere and the associated greenhouse effect.