Energy efficiency of miscanthus insulation for building walls in various world climates

The building sector is a major contributor to global energy consumption, highlighting the need for efficient and sustainable insulation materials. This study investigates the thermal and energy performance of miscanthus-based bio-sourced insulation applied to exterior building walls across five climate zones defined by the Köppen–Geiger classification. The effects of wall orientation and solar exposure are also examined. A two-dimensional transient heat transfer model based on an implicit finite difference method was developed in MATLAB to simulate heat transfer through multilayer walls. Heating and cooling loads, indoor surface temperatures, and decrement factors were evaluated for insulated and uninsulated configurations. Results show that miscanthus insulation significantly reduces energy demand in all climates. Heating loads in cold regions were reduced by more than 95%, while cooling loads in hot and mixed climates decreased from values exceeding 1.3 kWh/m² to below 0.1 kWh/m². Insulated walls maintained indoor surface temperatures close to comfort set-points and strongly attenuated external temperature fluctuations, regardless of orientation. These findings demonstrate that miscanthus-based insulation is an effective bio-sourced solution for improving thermal comfort, reducing building energy consumption, and supporting sustainable and climate-responsive building design.