The buildings sector accounts for about 40% of final energy consumption in Germany, and by far the largest part of this is due to old buildings. In total, more than 80% of the final energy consumed in households is used for space heating and hot water (Federal Statistical Office 2010). Implementing the economically worthwhile measures for reducing energy consumption in the buildings sector would permit at least a 20 percent reduction in Germany‟s total emissions by 2020 (McKinsey 2007).