Treats the research programme initiated by the Ministry of Research and Technology with the aim of achieving a more rational use of energy in dwellings by air conditioning and ventilation measures. Points out that domestic heating is responsible for around 40% of energy consumption in West Germany, of which about one third is dissipated as ventilation heat loss. Treats the approach of the research into reducing this ventilation heat loss without worsening the indoor air quality and the areas where this research overlaps other national and international research projects.The project is in two parts< 1. Fundamental investigations and analyses<2. Gaining practical experience and empirical knowledge by means of a large number of demonstration installations. Concentrates on a review of current activities in phase one.