Comparative analysis of sustainable design strategies in Sanheyuan vernacular and modern dwellings: effects on summer microclimate in Sha Tun village, Handan, Hebei Province, China

Climate-adaptive design strategies have been incorporated into rural vernacular dwellings in China for centuries. Despite this, limited research addresses their adaptive thermal performance during peak summer months. This study examines the microclimate regulation of Sanheyuan vernacular and modern dwellings in Handan, Hebei Province, China. Air temperature, relative humidity, and wind speed were measured on a typical summer day at several locations, including courtyards, semi-outdoor spaces, and indoor living areas. The results indicate that Sanheyuan vernacular dwellings, which employ high-thermal-mass materials, flexible openings, and courtyards with multi-layered vegetation, provide substantial thermal buffering, maintain stable indoor temperature and humidity, and enable effective natural ventilation. The total heat transfer coefficient (HTC) reached values as low as 338.88 W/K. Sanheyuan vernacular dwellings maintained peak indoor temperatures 2.6°C lower, relative humidity 5–8% higher during peak hours, and average wind speeds 1.2 m/s higher than modern rural dwellings. These features improve diurnal thermal comfort, support rapid nocturnal cooling, and reduce the heat island effect without mechanical systems. The findings demonstrate that passive design strategies in Sanheyuan vernacular dwellings offer low-energy, climate-resilient solutions for contemporary rural housing. This study provides quantitative evidence supporting the integration of heritage-inspired vernacular designs into modern rural housing developments.