Assessment of Passive Design Strategies for Thermal Comfort in Tropical Residential Buildings Ogbomoso, Oyo State, Nigeria

Abstract

Rapid urbanization and rising temperatures in tropical regions have increased the need for climate-responsive residential buildings that provide thermal comfort while reducing dependence on mechanical cooling systems and mitigating greenhouse gas emissions. The growing preference for thermally inappropriate modern construction materials, compact layouts, and inadequate ventilation in contemporary housing further exacerbates indoor heat gain and reduces thermal comfort. Therefore, this study evaluates the effectiveness of passive design strategies for enhancing thermal comfort across selected residential building typologies in Ogbomoso, Nigeria. A mixed-method approach was adopted, combining a structured questionnaire survey of 307 residents with field measurements of air temperature, relative humidity, air velocity, and heat stress index. Descriptive statistics were used to analyze occupants' perceptions of thermal comfort and the prevalence of passive design strategies, while environmental measurements assessed the thermal performance of different residential building typologies. The findings indicate that natural ventilation and external shading were the most widely adopted passive design strategies, although their implementation varied across residential zones. Duplex buildings exhibited the most favorable thermal conditions, recording the highest air velocity (0.8 m/s), the lowest indoor air temperature (29.1°C), and the lowest relative humidity (60%). In contrast, Brazilian (face-me-I-face-you) buildings recorded the poorest thermal performance, with the highest indoor temperature (31.5°C), relative humidity (68%), and a heat index of approximately 40°C, indicating a high level of thermal stress. The study concluded that building typology significantly influences the effectiveness of passive design strategies and indoor thermal comfort and that integrating climate-responsive passive design principles into residential planning and housing development can substantially improve occupant comfort and reduce cooling energy demand in tropical environments.