There is general agreement in Germany on the national targets for climate protection. The aim is to reduce greenhouse-gas emissions by 2050 to a level equivalent to 80 to 90 % of the figures for 1990. However, the energy-efficiency standard of most of the new-builds and refurbishment projects today can only be described as average, which is far short of what is required if the goals for the private residential sector are to be met. Significantly higher standards are needed, certainly at the latest by 2015/20.One cost-efficient and practical solution is to consistently apply passive-house technology to new-builds and also to future energy-efficiency improvements in the existing housing stock. How this would impact on greenhouse-gas emissions through to 2050 was the subject of a dissertation by the author. This article presents his main findings.