Evaluating the Impact of Passive Design Strategies on Mid-Rise Condominium Performance in Eti-Osa, Lagos, Nigeria

Abstract

Passive design strategies have emerged as an effective approach to improving thermal comfort, reducing operational energy consumption, and enhancing environmental sustainability in residential buildings, particularly within tropical climates. This study evaluated the impact of passive design strategies on the environmental performance of mid-rise condominiums in Eti-Osa with a view to developing sustainable design recommendations for Sangotedo, Lagos, Nigeria. Existing literature identifies natural ventilation, daylighting, building orientation, external shading, landscape elements, and sustainable building materials as key passive strategies capable of improving indoor environmental quality while reducing dependence on mechanical cooling systems. A mixed-methods research design was adopted, involving climatic assessment, field observations, architectural evaluation, and questionnaire surveys administered to 248 residents of selected condominiums. Data were analysed using descriptive statistics, Mean Weighted Value (MWV), Total Weighted Value (TWV), and Relative Importance Index (RII).The findings revealed that large windows for daylighting (MWV = 3.76), cross ventilation (MWV = 3.71), and sun-shading devices (MWV = 3.66) were the most widely incorporated passive design features, whereas landscaped gardens (MWV = 1.44), shaded outdoor sitting areas (MWV = 1.48), and the use of natural materials (MWV = 1.42) were inadequately integrated. Occupants generally perceived their indoor environments as thermally comfortable, with comfortable indoor temperature (MWV = 3.65), natural ventilation effectiveness (MWV = 3.62), and satisfactory indoor air quality (MWV = 3.47) recording positive ratings. The major barriers to effective implementation were insufficient funding (RII = 0.75), lack of awareness of passive design principles (RII = 0.75), poor maintenance culture (RII = 0.73), and inadequate design consideration (RII = 0.71). The study concludes that although passive design strategies have contributed positively to thermal comfort and environmental performance in the selected condominiums, their implementation remains selective rather than holistic. It recommends the adoption of integrated climate-responsive design approaches that prioritize cross ventilation, daylight optimization, appropriate building orientation, landscape-based cooling strategies, and sustainable material selection, alongside increased stakeholder awareness and policy support, to enhance the performance of future mid-rise residential developments in Sangotedo and similar rapidly urbanizing communities in Lagos State.