Optimising sustainability through digital tools: Energy and carbon comparative analysis of brick, concrete and wood frame construction envelopes in Coimbra residences

Abstract

Global warming, driven by greenhouse gas emissions, threatens to exceed the 2°C threshold set by the United Nations Convention on Climate Change. The construction sector contributes to 37% of global emissions, largely due to embodied carbon from materials. This study evaluates the environmental im-pact and energy performance of three construction assemblies for a single-family house in Coimbra, Portugal: traditional ceramic brick, aggregate con-crete blocks, and wood frame. A BIM-based method integrating lifecycle stages (A1–A3, B4, B6) was applied to analyse embodied and operational carbon. The energy simulations, conducted using LadyBug and HoneyBee in the Grasshopper environment, revealed that the wood frame assembly achieved the best performance, reducing the annual thermal load by nearly 2000 kWh compared to concrete assemblies. Embodied carbon emissions were significantly lower for wood frames (76.99 kgCO₂e/m²) than ceramic brick (478.0 kgCO₂e/m²) or concrete blocks (461.4 kgCO₂e/m²), highlighting the carbon sequestration benefits of timber. Despite better operational per-formance, concrete options exhibited higher long-term emissions due to poor thermal efficiency. By integrating energy simulations into lifecycle analysis, designers can prioritize solutions that achieve a balance between thermal per-formance, occupant comfort, and environmental impact, ultimately supporting the global goal of carbon neutrality, while considering a holistic approach. While wood frame assemblies offer a sustainable alternative, broader strate-gies, such as integrating circular economy principles and enhancing public awareness, are vital for systemic change. Limitations, including early design-phase data and incomplete lifecycle stages, highlight the need for further re-search to refine sustainable building practices in Portugal and beyond.