This research investigates the application of phase change material (PCM) in a solar water heating system (SWHS) to improve the efficiency of thermal energy storage (TES) and provide an extended hot water supply for domestic consumption. The study focuses on paraffin wax latent heat storage (LHS) and evaluates three experimental case studies. A compact flat plate SWHS (Case 1), a thermosyphon system with top mounted PCM (Case 2), a conventional system enhanced using RT42 paraffin under various inlet conditions (Case 3). The results showed that the placement of PCM, melting point selection, and operational parameters significantly impact system performance. The thermosyphon system demonstrated the most balanced improvement with enhanced efficiency of 16% and a prolonged discharging period of approximately 7 h. After analyzing the findings of these case studies an experimental design was proposed for implementation at the German university of Technology (GUtech) ECO-HOUSE in Oman. However, due to financial circumstances, the experiment was not conducted. The experimental design took the local climatic conditions into consideration, and it aimed to validate the theoretical results in future work. Moreover, utilizing PCM in SWHS under optimized thermal conditions has been proven to improve overall system performance.