###### Abstract
Life cycle cost analysis method was used in cost calculations for the province located in the fourth climate zone. While the lowest insulation material thickness was obtained in the case of using XPS, payback periods in all examined cases were between 0.9 and 4 years. In the study conducted by [PERSON] et al. [10], four different wall types and eight different insulation materials were selected for a building located in Sivas, Turkey. By considering the heating factor, the optimal insulation thicknesses, payback period, and energy savings were estimated through a life cycle cost analysis  
[PERSON] [11] changed the materials used in wall structures that have an effect on energy consumption in buildings. He developed an economic mathematical model to investigate the energy cost of a building in Indonesia when a new composite material brick he designed was used with traditional bricks. The objective of the study conducted by [PERSON] et al. [12] was to investigate the optimum insulation thickness of a typical wall for Andalusia, Spain, which has Mediterranean and semi-arid climate characteristics. A life cycle cost analysis was employed to facilitate the calculations. The heating and cooling degree days utilized in the calculation were obtained through three distinct methodologies (hourly, UKMO, and ASHRAE), and the outcomes were subjected to a comparative analysis. In their study, [PERSON] et al. [13] examined the deterioration of insulation performance in aged buildings, considering a total of 62 buildings. The thermal transmittance of the external walls of the selected buildings was measured and compared with the results of the improvement projects. After the earthquake in Zagreb, [PERSON] et al. [14] discussed the application of the energy integrated approach to city buildings in their study and investigated building envelope energy efficiency measures. The aim of exploring ways for sustainable development is to leave a clean environment for future generations while improving the quality of life. Turkey is a country whose energy demand is increasing rapidly every day with its growing population and developing economy, but its domestic energy resources are limited and it imports a large part of its energy demand [15; 16]. Two earthquakes struck Turkey on 6 February 2023. A total of 10 provinces have rebuilt their residences. In accordance with Turkish Standards 825, these provinces are classified into three climate zones. Hatay and Adana are in the first-degree day zone, while Adyaman, Diyarbakir, Gaziantep, Kahramanmaras, Kilis, Sanlurfa, and Osmaniye are in the second-degree zone. Malatya is a third-degree day zone. This research identifies optimum insulation thickness for rebuilding efforts in these regions. The location of Turkey and the provinces affected by the earthquake discussed in the study are given in Figure 1.  
The findings will analyze the insulation strategies employed in the selected provinces, providing insights into their efficiency and economic impact. This research contributes to the reconstruction efforts in regions affected by earthquakes by identifying optimal insulation solutions. Different insulation thicknesses were identified as a result of using various fuel types in the calculations. However, the required insulation thickness itself does not change with different fuel types. The insulation thicknesses presented here are the values calculated to achieve the highest financial gain over a specific time period, taking into account economic  
Figure 1: The provinces with different degree days affected by the earthquake. factors. This should not be interpreted as the insulation thickness varying with changes in fuel type. The observed differences are primarily due to fluctuations in fuel prices. This study explores the importance of thermal insulation in residential buildings to improve energy efficiency, reduce environmental pollution, and lower energy costs. It emphasizes finding the optimum insulation thickness, which balances investment and energy savings.