Evaluating expanded polystyrene insulation for enhancing energy efficiency in residential buildings: a scalable model from Mozambique

Purpose This study aims to posit that Expanded Polystyrene (EPS) insulation represents a critical, yet underutilized, intervention for achieving sustainable development in tropical regions. A scalable, evidence-based framework was developed and validated to evaluate the energy, economic and environmental performance of EPS in resource-constrained contexts, with Mozambique as a primary case study. Design/methodology/approach A calibrated energy simulation model of a typical Mozambican household was developed using DesignBuilder software. Comparative analyses quantified energy savings against a baseline model, while cost-benefit and environmental assessments evaluated economic viability and carbon dioxide (CO2) emission reductions. The methodology integrated local climate data, material properties and economic conditions to ensure contextual relevance and global scalability. Findings The analysis identified 95 mm as a cost-effective EPS thickness for roof insulation in Mozambique’s tropical climate. This configuration reduced annual cooling energy consumption by 30.1% (from 5,392.04 kWh to 3,767.28 kWh) and decreased operational CO2 emissions by 13.52% (from 944.73 kg to 816.99 kg). The initial investment of MZN 56,354.78 (US$ 882.08) was recovered within a discounted payback period of 6.3 years, demonstrating strong financial viability. Originality/value This research pioneers a holistic and scalable framework for assessing building insulation in tropical developing countries, a domain with a significant research gap. By synthesizing localized climatic, economic and material data, it provides a replicable blueprint for policymakers and builders to enhance energy efficiency and climate resilience, advancing global sustainable development goals.