A Study of the Sound and Thermal Insulation of Wood Façade Assemblies by Considering Environmental Impact Aspects

Timber façade assemblies are increasingly used in residential construction for reasons including prefabrication, construction speed, and lower environmental footprint. However, adequate acoustic performance in lightweight assemblies requires additional materials, which affect both thermal performance and embodied carbon emissions. This study investigates the trade-offs between airborne sound insulation (Rw), thermal transmittance (Uvalue), and embodied carbon in timber façade assemblies. 382 assemblies, organized into seven families, were compiled from the literature. Correlation and Pareto-based multi-objective analyses were applied to evaluate the relationships among the three performance metrics. The findings indicate a positive correlation between acoustic and thermal performance across families, with R2 values ranging from 0.69 to 0.88. Nevertheless, no correlation was found between acoustic insulation and embodied carbon, indicating that acoustic improvements can be achieved without proportional increases in environmental impact. Pareto analysis identified 45 Pareto-optimal assemblies representing the best achievable trade-offs between the three criteria. For façade assemblies with overall thickness ranging from 287.5 to 477 mm, increasing insulation thickness from 120 to 300 mm in 40 mm increments improves acoustic and thermal performance by 1 dB and 0.02–0.04 W/m2 K, respectively, at an embodied carbon cost of 2–3 kg CO2 eq/m2. A catalogue of seven representative assemblies is included in the article as a practical design reference.