In September 2010, the German government introduced a new set of energy targets for the building sector, according to which the national building stock should be almost CO2 neutral by 2050, and the primary energy demand of residential buildings should be reduced by as much as 80?%. In order to achieve this target, in future, yearly 2?% (instead of 1%) of all residential buildings should undergo the equivalent of a full energy-efficiency renovation. According to estimates, it would cost nearly 9 billion Euros per year, starting from 2020, to reach this goal. By comparison, the government are currently only investing 1,5 billion Euros per year in the public funding programmes for energy-efficient renovation and construction of energy-efficient new buildings. Where the remaining funds should be sourced has erupted into a heated public debate. (Jakob Schoof)