Ventilation strategies and energy dependence in tropical office buildings: Implications for sustainable urban development in the global south

In rapidly urbanising tropical cities, the growing dependence on mechanical cooling in high-density office buildings presents critical challenges for energy sustainability, indoor environmental quality (IEQ), and climate resilience. This study examines the adoption and performance of ventilation strategies in multi-storey office buildings in Abuja, Nigeria, situating the analysis within the nexus of Sustainable Development Goals (SDGs) 7, 11 and 13. A mixed-methods approach was employed, integrating structured field observations of five high-density office buildings with a questionnaire survey of 205 occupants. Observational data documented architectural and mechanical ventilation characteristics, while survey responses captured user reliance on ventilation modes and perceived thermal comfort. The assessment of thermal comfort perception was conceptually informed by adaptive comfort principles consistent with ASHRAE Standard 55 for naturally ventilated and mixed-mode buildings. Descriptive statistics and chi-square analysis were used to evaluate relationships between ventilation strategies and occupant experience. Findings reveal a systemic reliance on hybrid and fully mechanical ventilation, with no building operating solely on natural ventilation. Despite the nominal inclusion of operable windows, prevalent typologies, primarily sliding and awning, significantly constrain effective airflow. Additionally, spatial configurations often include enclosed zones without natural ventilation, reinforcing reliance on energy-intensive cooling systems. A statistically significant association between ventilation mode and thermal comfort (χ² = 17.444, p < 0.01) indicates higher comfort levels in air-conditioned environments, highlighting performance gaps in passive design integration. The study exposes a critical disconnect between passive design intent and functional performance, with implications for rising urban energy demand and carbon emissions. It advances empirical evidence from Sub-Saharan Africa and calls for integrated, climate-responsive design approaches that align architectural form, ventilation strategy, and energy efficiency to support sustainable urban development. Unlike prior studies that primarily rely on simulations or occupant-only assessments, this study combines field-based architectural observation with occupant perception analysis to evaluate the operational realities of hybrid ventilation systems in tropical African office buildings.