Though the energy consumption of buildings is supposed to decrease after a retrofit, several studies show that the energy performance does not increase as much as it would be expected and that a significant gap between the estimated and the real energy savings - called “rebound effect” - occurs. This deviation can partly depend on the model used for the energy performance evaluation, but changes in the occupants’ behavior after a thermal retrofit of an existing dwelling are also revealed. The paper examines the influences of occupant behavior on the energy savings for some retrofitted Italian residential representative buildings. Some typical use patterns are defined according to statistics of the national census of population and dwellings and the expectations of the building occupants are specified before and after the retrofit. The main objective is to investigate the elasticity of the energy consumption in function of the occupancy parameters before and after the application of high energy efficiency improvements. The analysis is carried out by means of a simplified energy performance assessment model. The outcomes of this study consist in defining synthetic indicators for the quantitative assessment of the rebound effect.