Modern buildings are usually made in a way that makes the efficient use of energy possible. Nevertheless, there are still open questions such as: - Whether the perception of buildings as power plants using renewable sources of energy is justified in relation to energy inputs and CO2-emissions, - Whether the currently used energy demand calculations should not be complemented by information on energy inputs needed for building assembly and manufacturing, - Whether alternative and lasting (sustainable) building materials would be a kind of solution, - Whether the energy savings by building industry in the course of manufacturing could lead to other architectural solutions than so called "low-energy design", and - Whether it is possible in the design phase to consider the questions of CO2-emissions due to the life cycle of buildings at all? The aim of the planned conference is to discuss the above questions. Beyond that it should also create a kind of starting platform for the future information exchange and work in the respective standardization committees.