The introduction of the concept of sustainable building in the construction industry has led to different measures to reduce the environmental impact of building objects in the past decades. Because the built environment accounts for more than 40% of the total energy consumption in Europe (EC, 2002), energy saving techniques receive much attention. In the Netherlands the overall energy performance of houses can be calculated by three different indicators. In order to compare these Energy Performance Indicators (EPI) seven residential objects are evaluated. This study reflects on the financial efficiency of energy saving measures, techniques or technologies by introducing a new variable for the gains related to the value increase of houses. It is found that the energy performance of houses has gradually improved during the last century. The results of the financial analysis point out that the return on investments is high in Dutch real estate.