Investigating Thermal Comfort in Vernacular Building Typologies for Contemporary Housing Design in the Sahel Zone of Nigeria

Vernacular architecture in Nigeria's Sahel zone, encompassing Borno, Yobe, and parts of Katsina states, has evolved over centuries to manage extreme heat through passive design strategies including thick mud wall construction, courtyard spatial organisation, and strategic orientation relative to prevailing winds. As contemporary housing construction increasingly replaces vernacular typologies with concrete block structures, occupants are experiencing thermal discomfort that drives costly and environmentally burdensome air conditioning use. This study investigates the thermal performance of selected vernacular and contemporary housing typologies in Maiduguri and Nguru through environmental monitoring and occupant survey methods. Indoor air temperature, relative humidity, and mean radiant temperature are measured at six-hour intervals over eight weeks in a dry season period across four vernacular and four contemporary building samples. Thermal comfort is assessed using the adaptive thermal comfort model and a structured occupant thermal perception survey administered to three hundred and twelve residents. Findings confirm that vernacular mud brick structures consistently maintain indoor temperatures five to nine degrees Celsius below contemporary concrete structures during peak afternoon heat periods. Occupants of vernacular buildings report significantly lower thermal discomfort and near-zero reliance on mechanical cooling. The study extracts twelve passive design principles from the vernacular typologies and develops a Contemporary Sahel Housing Design Guide incorporating these principles into a concrete block construction framework. Recommendations target the Federal Ministry of Works and Housing's public housing design standards. Keywords: vernacular architecture, thermal comfort, Sahel zone, passive design, housing design.