Evaluating thermal and energy efficiency analysis of novel recycled textile application as a sustainable insulation

This study explores the use of recycled textile waste – specifically cotton, linen, and denim – as thermal insulation materials for buildings. Layered samples were prepared using standardized cutting, compression, and stabilization methods. The newly defined block-shaped material conductivity was measured under steady-state conditions using a validated experimental approach. Results showed conductivity values ranging from 0.045 to 0.051 W/(m·K) for cotton, 0.052 to 0.058 W/(m·K) for linen, and 0.050 to 0.059 W/(m·K) for denim. A notable linear correlation was found between fabric layer and thermal conductivity (R² = 0.78–0.81) in dried status. These values were then used in simulation-based multi-objective optimization, revealing energy savings of 33–35% compared to the validated baseline of ASHRAE Cases of 600 and 900. The findings indicate that recycled textiles offer thermal performance comparable to conventional insulation materials at similar, presenting a promising low-cost alternative. The study highlights the potential of textile wastes as a sustainable insulation option within a circular economy framework. While these results suggest significant environmental benefits, future research on long-term durability, fire resistance, moisture absorption, and quantitative life cycle assessment (LCA) is suggested to fully assess its long-term viability.