Dynamic substitution processes between energy-conversion techniques are very important phenomena for the restructuring of energy systems. Using the method of synergetics, we develop a probabilistic model framework for individual decisions and their effects on the macroscopic configuration of energy supply systems. The derived probability transition rates are associated with socioeconomic parameters that are the basis for individual decisions. We state preliminary results of a case study for the room heating of private households in the former West Germany, which are based on a small data sample and a nonrepresentative poll We find that the number of healing systems of one type which are already installed, their ease of use, and the cost are the most important parameters for the selection of a new heating system. Using the estimated parameters, we simulate the diffusion of a new type of heating system, which is regarded as better than all the others, into the energy supply system. Tts market share will reach 11-18% after 35 years.