Optimising Indoor Air Quality and Thermal Comfort in Residential Buildings: Integrating Passive Strategies and Low-Cost Monitoring Technologies in Sub-Saharan Africa

<p dir="ltr"><i>This study investigates the comparative impact of passive design strategies and low-cost environmental monitoring on indoor air quality (IAQ) and thermal comfort in low-income residential buildings in Abuja, Nigeria, a hot-humid climate. Focusing on three case study locations: Lugbe, Dutse Alhaji, and Bwari. The research distinguishes between naturally ventilated homes (NVH1) and air-conditioned homes (ACH2) to evaluate differences in performance and occupant experience. The study assesses the effects of polyurethane (PUR) roof insulation, PUR wall insulation, and stabilised lateritic brick (SLB) construction in NVH1 homes and compares them to adjacent ACH2 homes using EnergyPlus simulations, field monitoring, and validated low-cost sensors. The results show that NVH1 homes upgraded with passive strategies had indoor temperatures that were up to 5.0°C cooler and maintained CO₂ levels below 900 ppm, achieving better air quality than homes with air conditioning, despite their temperatures fluctuating more. CIBSE TM52 and EN16798-1 assessments confirmed significant reductions in overheating risk. Post-occupancy evaluations (n = 127) showed higher comfort satisfaction in NVH1 homes where post-retrofitting is adopted in the future, alongside reduced reliance on fans. Meanwhile, ACH2 homes faced performance constraints due to frequent power interruptions and high energy costs. The findings support the use of scalable, low-cost passive retrofitting as a resilient and equitable alternative to mechanical cooling in Sub-Saharan African housing contexts.</i></p><p><br></p>