As the energy demand used for space heating accounts for 78% of EU15 household delivered energy consumption, significant reductions in energy demand can be achieved by promoting low-energy buildings. Our study investigates three building types: the standard house, the low-energy house and the passive house. As more far-reaching measures concerning energy savings usually lead to higher investments, the aim of our study is to perform an economic analysis in order to determine the economic viability of the three building types. (c) 2007 Elsevier Ltd. All rights reserved.