Energy Performance Retrofit of a Semi-Detached Chalet in a Hot-Arid Coastal Climate: The Case of Ain Sokhna, Egypt

This study examines how iterative design interventions can enhance the environmental and energy behavior of a coastal residential building located in Ain Sokhna. A baseline configuration is first established using quantitative performance metrics related to thermal behavior, electricity demand, and domestic hot water production. A sequence of passive, hybrid, and active measures is then introduced and evaluated through comparative simulations under local climatic conditions. The analysis emphasizes envelope characteristics, solar control, natural ventilation potential, and on-site renewable integration. Results demonstrate measurable reductions in cooling demand and overall annual energy use, while maintaining indoor comfort within acceptable thresholds. The study highlights the value of scenario-based evaluation and cross-tool verification for supporting evidence-based decision-making in residential buildings located in hot-arid coastal contexts.