The environmental problem keeps growing on and it needs immediately an effective solution, in order to improve the quality of life and to save the planet which is now on risk. In this paper there is a general presentation of the problem that buildings, which are not consistent with the current technical standards, are facing nowadays. Also, what the Greek law provides so it could be abide by that of the EU in the issue of the construction of buildings. The renewable resources of energy and the ways that they can be used at a house level, are described as well.

 The most popular standards of energy certification, the goals they are trying to achieve and the methods that they use are referred in short. In addition, successful examples of “passive” houses, the analysis of the ways that are used in order to succeed law energy consumption and the materials are used, are included in the paper. Finally, we describe the alternative ways with which an existing house can reduce the heating load and also the ways of the whole reduce of its energy requirements until the house reaches the level autonomy.