Evaluation of Post-Occupancy Performance of Green Buildings in Nigerian Institutional Contexts

Green building certification programmes such as LEED and EDGE are increasingly applied to institutional buildings in Nigeria, but rigorous post-occupancy evaluation of their actual energy, water, and occupant satisfaction performance is largely absent from the Nigerian professional literature. This study evaluated the post-occupancy performance of five certified or declared green buildings in institutional settings across Nigeria, including two universities (South West and South East), one federal government ministry building (FCT), one healthcare facility (South South), and one state secretariat (North Central). Post-occupancy evaluation followed the RIBA Post-Occupancy Evaluation toolkit, covering energy consumption benchmarking, water use performance, indoor environmental quality measurement, and occupant satisfaction surveys (n = 250). Results showed that three of the five buildings achieved energy use intensities below their design targets, with the best performer achieving 40% below target. Water consumption was within design targets in four buildings. Indoor air quality monitoring showed elevated CO2 concentrations above 1,000 ppm in workspaces of two buildings, indicating inadequate mechanical ventilation operation. Occupant satisfaction was moderate (mean: 3.2 out of 5), with thermal comfort the lowest-rated dimension. The study concludes that certified green buildings in Nigerian institutional contexts generally outperform conventional buildings but fall short of design performance targets. Mandatory post-occupancy evaluation reporting for all green-certified buildings is recommended.

Keywords: post-occupancy evaluation, green buildings, energy performance, institutional buildings, Nigeria