The passive strategies are one of the most effective strategies for energy efficiency and thermal comfort performance either in newly constructed or in retrofitting existing buildings. The optimization is a process or methodology of making a system or decision as advantageous as possible, considering all relevant influencing factors. In the optimization process, a special decisionmaking tool should be properly set in order to cover the described configurations. This paper presents approaches to explore reducing energy consumption and increasing the thermal comfort in five typical residential buildings in Sulaimani city in Iraq, through investigating the optimization of different passive refurbishment strategies. The approaches are supported by simulation of different scenarios, applying computational techniques. In addition, an own developed decision support tool was proposed to assess and complete the optimization process. The most convenient passive strategies for optimization were summarized and the optimum models were proposed. The results revealed that improvement of energy efficiency and thermal comfort in the investigated buildings depends mostly on construction technique, materials used, and design of building body shape (A/V-ratio) and natural ventilation.