Trade-off between sound insulation performance and cost-optimality in a residential nZEB

Until now, design of new high performance buildings has been focused on the energy performance but lacks to be addressed as a holistic problem taking into account all the aspects of a performance of a building. This work strives to study and optimize at once, the energy performance of a building and the sound insulation performance of its facades. In particular, energy and acoustic performances of different building facades, made of two different wall types, were compared taking in account the cost-optimized design of a building. The proposed methodology couples a cost-optimization of the building energy model made though TRNSYS® and GenOpt, with an evaluation of the sound insulation indexes with Matlab®, and it was applied to a French single-family case study. The results show that the cost optimal energy performance level of such case study is somewhere between 40 and 47 kWh/m².year, while the sound insulation efficiency of the façade can reach a wide range of values. However, the proposed methodology allowed to highlight several design solutions fulfilling the requirements in term of energy, cost and acoustics performances.