Assessing the life cycle environmental impacts of modular construction: a US case study of a prototype housing unit

The construction industry is a major contributor to greenhouse gas emissions, resource depletion, and waste generation. Modular construction (MC), which involves prefabricating building components off-site and assembling them on-site, has emerged as a promising strategy to reduce project time, cost, and environmental impacts. However, there is still limited comparative life cycle data available when measuring against traditional construction (TC). This study evaluates the environmental performance of MC versus TC in the United States through life cycle assessment (LCA). A mixed-methods approach combines a literature review with a comparative case study analyzed through BIM-integrated LCA tools. Results indicate that MC can achieve up to 54% lower embodied carbon per square foot and 45% lower emissions per kilogram of material, mainly due to efficient material use, prefabrication, and minimized on-site waste. Controlled factory-based production also enhances optimization and reduces environmental burdens during the construction process. These benefits, alongside faster project delivery, position MC as a viable pathway toward sustainable construction, particularly for affordable housing and post-disaster recovery. Key limitations include data variability and the restricted scope of current LCA datasets, highlighting the need for broader, multi-regional studies and diverse building typologies to strengthen future assessments.