Both, the technical characteristics of buildings, e.g. insulation standards, and the utilisation patterns of households are important determinants of the space heating demand of private households. Therefore, this paper examines to what extent socio-economic characteristics of households (household size, social position, income, etc.) are suitable to explain household's behaviour concerning space heating given technical building characteristics. On the other hand, energy efficiency factors derived from technical simulation models are scrutinised. The empirical basis of this analysis is the official household survey 1988 for West Germany containing about 44,000 data sets, Therefrom it turns out that the German insulation standards of buildings have been less effective in the past than assumed on the basis of technical simulations. By means of scenario calculations projections of the heating energy demand for space heating in the future are obtained, sketching the effect of different possible socio-economic developments on the space heating consumption and analysing different political options concerning building insulation standards for new buildings and the existing building stock.