Life cycle energy use and carbon emission of a modern single-family residential building in Nepal

The rapid urbanization and rural-urban migration trends have led to an increase in building construction activities, shifting from traditional practices to modern concrete structures. However, this transition has imposed significant environmental pressures, including heightened resource and energy demands, resulting in increased emissions. To gauge the environmental impact of construction, a thorough examination of each phase is crucial. This study used the Life Cycle Assessment (LCA) tool, based on ISO 14040:2006, ISO 14044:2006, and EN 15978:2011, to evaluate the carbon dioxide equivalent (CO₂-eq) emissions throughout the complete life cycle of a modern single-family residential building. The findings reveal a total energy use of 6411.33 MJ per square meter and emissions of 718.35 kg CO₂-eq per square meter over the building's lifespan of 50 years. Notably, the production of building materials and the construction phase contribute to the highest percentage (60.29%) of the total life cycle emissions owing to 49.51% of energy use. In contrast, emissions during the operational phase are relatively lower, attributed to increased electricity usage for cooking and minimal energy consumption for heating and cooling. Additionally, the study suggests that achieving complete electricity sufficiency within the country could reduce building emissions by 39.30%, as fossil fuel-based imports from India would be replaced with cleaner hydroelectricity.