Mitigating Climate Change Impacts in Buildings using Passive Design Strategies: Putting Costs to Contexts

Across the global construction industry, climate change mitigation is achieved using design and construction practices that optimise energy efficiency. The scope of these practices varies with regional contexts. In Nigeria and other regions, their adoption is slow due to the absence of cost benchmarks to drive their implementation decisions. In this study, we appraised the first cost premium (FCP) and the payback periods of selected passive designs strategies (PDS) in retrofitted residential buildings. Using cost data from two categories of 150 retrofitted residential building designs, analytical estimating processes showed that integrating five PDS would attract FCP totaling ₦ 3,612.17/m2 and ₦ 9,250.00/m2 for bungalow and maisonette buildings. Procuring these FCPs also has varying levels of reduction in energy consumption that are necessary to mitigate the impacts of climate change. The financial benefits in energy savings from two PDS (roof insulation and overhang) could only pay-off the FCP for bungalows with cost-savings of 81%, while reducing the FCP for maisonettes by 70% in one year. The discounted FCP after one year becomes zero for the bungalow and ₦ 2,650.00/m2 for the maisonette. The short-term payback periods provide a significant incentive for developers to adopt energy-efficient designs in building development