This study was born in the context of new challenges imposed by the recast of Energy Performance of Buildings. The aim of this work is to provide a useful method to deal with a huge number of simulations corresponding to a large number of single-family house configurations in order to optimize a constructive solution from both technical and economical point of view. The method combines the use of TRNSYS, building energy simulation program, with GenOpt, Generic Optimization program. The reference building is a low-consumption house case-study situated in Amberieu-en- Bugey, Rhône-Alpes, France. After a short description of the case-study and of TRNSYS model, the link and the configuration files which have been created between the simulation program and the optimization software are illustrated. A first parametric study is performed in order to evaluate the impact of variation of various parameters of envelope and shading elements on the total annual energy consumption for heating and cooling. As a second study, the global cost method is applied to the case-study, and GenOpt is used to determine the cost optimal level of the reference building. Beyond the result, we think this study shows useful method and tools that could support technical and cost optimal level research, providing an easy and fast way to explore various building configuration with a huge number of simulations, as requested by European Standard.