From heritage to high performance: A scalable retrofit strategy for energy-efficient housing in Yemen’s Hot-Arid Zone

This study proposes a practical and culturally responsive retrofitting strategy for multi-story residential buildings in Sana’a, Yemen, a city with a hot arid climate and a growing energy burden owing to an inefficient building stock. A dynamic energy model was developed in DesignBuilder and calibrated using 12 months of actual energy data (CVRMSE = 7.49 %, NMBE = −4.20 %), ensuring high accuracy in performance prediction. The retrofit approach integrates time-tested local design elements, such as the Mashrabiyah for passive solar control and regionally produced thermal insulation, with modern energy-efficient technologies, including low-emissivity double-glazing and high-efficiency LED lighting. These interventions were applied in stages and evaluated for their impact on energy use, costs, and carbon emissions. The results show a 70.7 % reduction in annual electricity consumption (from 1693 kWh to 495 kWh per unit), along with proportional savings in operational costs and CO₂ emissions. In addition to the technical performance improvements, the retrofit sequence also leads to clear operational cost implications through annual reductions in cooling-related electricity use. All results are derived from simulation-based analyses, as post-occupancy verification could not be conducted due to field constraints. This strategy is aligned with LEED regional priority credits, ensuring that local climate needs are met while adhering to global sustainability benchmarks. By combining traditional architectural knowledge with contemporary building science, this approach delivers high performance without compromising the cultural identity. These findings provide a replicable and scalable model for urban retrofitting in hot-arid regions, with significant implications for policy, affordability, and climate resilience. This study demonstrates that sustainable renovation can be both technically effective and socially meaningful in heritage-rich, resource-constrained contexts.