Nowadays, latent heat storage is becoming an imperative in building sector since it plays a crucial role in conserving energy through controlling the thermal comfort level. In this field, different storage systems based on phase change material show great performances in terms of energy saving, leading to a significant improvement of occupant thermal comfort. In this work, the thermal behavior and energy efficiency of a residential house incorporating various phase change materials (RT18HC, RT21HC, RT25HC, and RT28HC) in Mediterranean climate region were investigated via numerical simulations. EnergyPlus software was used to analyze the thermal performance of phase change materials applied to the interior wall surfaces of a simplified building model in El Jadida city. The integration of different single and double phase change material layers has been evaluated based on various concepts such as the average temperature fluctuation reduction and the monthly energy saving. The study showed that low melting point phase change material outperforms in terms of heating load, while phase change material with high melting temperature favors the cooling performance. Moreover, the results show that double-layer systems formed by two distinct phase change materials exhibit higher performance than a single phase change material layer throughout the whole year. The annual energy saving rate reaches 41.42% and 55.41% when using single and double phase change material layers, respectively. Finally, we opted for an optimum double-layer system for lower energy consumption in the selected city.