Multi-criteria optimization of cross-laminated timber (CLT) wall systems for energy, carbon, and cost performance: a case study for Türkiye’s climate zones

Abstract

Given the construction sector`s role in climate change, this study investigated the energy performance of cross-laminated timber (CLT) as a sustainable alternative to reinforced concrete in Turkish residential buildings. A mid-rise building, in Türkiye, was modeled using DesignBuilder software and redesigned with CLT structural components. Ten CLT wall assemblies were evaluated across five distinct climate zones (cold, hot-humid, hot-dry, temperate-humid, and temperate-dry) in terms of energy demand, embodied carbon emissions, and material cost. The results show that CLT walls can provide a 41% reduction in heating energy consumption and a 20% reduction in embodied carbon value compared to conventional systems in cold climate region of Türkiye. Across five climate zones, optimized CLT wall systems achieved heating energy savings between 30.0% (Diyarbakır) and 42.5% (Antalya), cooling load reductions of 5.3% (Erzurum) to 63.4% (Diyarbakır), and embodied carbon decreases up to 10.2% (Antalya). Material costs for the optimized scenarios were approximately 24%–29% lower than reinforced concrete alternatives. A multi-criteria optimization method was applied to identify the optimal wall design for each zone. This study presents one of the first comparative analyses of CLT walls across different climatic zones in Türkiye, providing practical insights into climate-responsive, region-specific, energy-efficient and low-carbon construction strategies.