Bioclimatic assessment and thermal comfort of traditional Riads in Fez Medina

• Courtyards act as natural regulators of microclimate and indoor comfort. • Bioclimatic tools and ISO 7730 indices assess thermal comfort performance. • Rammed earth walls show 12-hour thermal lag, reducing indoor heat swings. • U-values of walls and roofs meet Moroccan thermal regulation standards. • Envelope optimization cuts PPD dissatisfaction from 80% to about 10–12% This study investigates the bioclimatic performance and thermal comfort of a traditional courtyard dwelling, the Riad in Fez, Morocco, located in a climate characterized by hot summers and cold winters. The building reflects local architectural traditions through the use of indigenous materials, including rammed earth, stone, wood, lime, baked bricks, zellige tiles, and carved plaster. The analysis combines physical, qualitative, and behavioral parameters with standardized bioclimatic tools, including Mahoney Tables, Givoni’s psychrometric chart, operative temperature, and PMV–PPD indices, complemented by Moroccan thermal regulations. Thermal performance of the building envelope—comprising rammed earth walls, wooden–earthen roofs, and courtyard-oriented openings—was assessed through U-value calculations. Results show that passive strategies inherent to the courtyard design, together with the high thermal inertia of local materials, significantly improve indoor comfort conditions. Simulations based on ASHRAE 55 and ISO 7730 demonstrate a reduction of predicted dissatisfaction levels from over 80% to nearly 10–12% after envelope optimization. The findings highlight the resilience of traditional Moroccan Riads to climate variability and underline their relevance as case studies for sustainable thermal engineering and adaptive reuse.