Within the framework of the REBUS project the German building industry has been investigated regarding their energy concepts. The intention was to evaluate the establishment of renewable energy sources on the German market for new built houses and prefab houses in particular. For this purpose the products of 85 manufacturers of prefab houses have been analyzed. Of special interest was the application of heating and hot water systems driven by solar energy and biomass. The results show that both techniques are well accepted and established. Almost 90% of the manufacturers offer solar systems on request and almost 70% heating systems based on Pellets. 24% offered solar and 7% as standard options in their range. From the achieved figures the potential of the Swedish market can be worked out. Strategies to introduce renewable energy to a greater extent to Swedish house manufacturers and builders might also be found.