The four-year project SuFiQuaD has started in 2007 to develop a methodology that can be applied to optimize the Belgian dwelling stock. SuFiQuaD stands for Sustainability, Financial and Quality evaluation of Dwellings. The aim of the project is to optimize buildings considering their environmental impact, their financial cost and the quality they offer over the whole life cycle, from the production of primary raw materials to the final demolition and end-of-life treatment. In the first phase of the project the optimization methodology is developed: environmental impacts are analyzed by means of a life cycle assessment (LCA). The environmental impacts are then translated into environmental costs using a monetary valuation of the environmental impacts; financial costs are calculated based on life cycle cost (LCC) analyses; and the quality evaluation is based on multi-criteria analyses. The optimization of the three aspects (environmental costs, financial costs and qualities) is based on a Cost Benefit Analysis (CBA). By means of the CBA it is possible to identify the highest marginal quality improvement for the lowest additional financial and environmental costs. The developed methodology is translated into a tool and applied in this first phase of the project to a limited selection of dwelling types. In the second phase of the project, the methodology and tool will be applied to a series of representative dwelling types for the Belgian dwelling stock. The presentation at the ERSCP 2009 will elaborate on the developed methodology and the results of the first implementation with some selected dwelling types.