Investigation of Thermal Comfort Conditions in Residential Buildings in Maiduguri, Borno State

Maiduguri, the capital of Borno State in North East Nigeria, has one of the most extreme hot arid climates in the country, and understanding thermal comfort conditions in its residential buildings is essential for climate-responsive building design. This study investigated thermal comfort conditions in 40 residential buildings in three residential neighbourhoods of Maiduguri: GRA, Customs, and Gwange. Field measurements of indoor air temperature, relative humidity, mean radiant temperature, and air velocity were taken at three times of day (morning, afternoon, and evening) over four weeks during the hot dry season. Residents completed thermal comfort questionnaires adapted from the ASHRAE 55:2020 standard. The adaptive thermal comfort model and predicted mean vote were calculated and compared with measured conditions. Results showed that mean afternoon indoor temperatures reached 38.4 degrees Celsius, far exceeding the adaptive comfort upper limit of 31 degrees Celsius for naturally ventilated buildings. Relative humidity averaged 21% during the dry season, well below the comfortable range. Predicted mean vote values ranged from 2.1 to 3.4 (warm to hot) across all building types. Mud brick buildings showed significantly better thermal performance than concrete block structures (mean temperature differential: 4.2 degrees Celsius lower at peak afternoon). Only 12% of residents reported being thermally comfortable during afternoon periods. The study recommends that building regulations in Borno State incorporate mandatory passive cooling design requirements including cross-ventilation, roof overhangs, and high thermal mass materials.

Keywords: thermal comfort, residential buildings, hot arid climate, Maiduguri, passive cooling