In this study, a simulation - based multi - objective optimization was empl oyed to minimize energy loads, reduce CO 2 emissions and improve occupants’ health and comfort, considering cost - effectiveness of the design approach on two buildings of different typology – high rise and low - rise prefabricated buildings, in New Be l- grade, S erbia. Series of EEI (energy efficiency improvement) measures were impl e- mented, focusing optimization of building’s envelope and structure energy efficie n- cy, natural and mixed ventilation and HVAC systems optimal control, as well as o p- timization of PV inte grated building facade in synergy with the façade structure e n- ergy efficiency optimization. The main goal of the study was to verify the effectiv e- ness of the integrated design technics applied in both cases, by comparative analysis considering building typ ology, which determined the optimal solutions and a d- vantages for each building type. The results identify the certain differences not only in optimization of building’s envelope structure but also in RES integration (BIPV Panels). Building’s dynamic behavi our in Typical Meteor o logical Year of Belgrade has been analysed and optimized by the BPS - Building Performance Simulation .