Identifying Optimal Scenarios for Internal Insulation in Refurbishment Projects

Improving building energy efficiency is essential for reducing consumption and enhancing indoor comfort. When external insulation is not feasible—such as in historic buildings or economically disadvantaged contexts—internal insulation becomes a viable alternative. However, its hygrothermal performance is complex and depends on multiple factors, including condensation risks and discontinuities caused by structural elements. This study presents a Python-based tool designed to assess the feasibility of internal insulation, integrating data from Italian municipalities. The tool calculates the required insulation thickness, evaluates condensation risks, and compares pre- and post-intervention thermal transmittance and dynamic thermal performance. Numerical simulations in COMSOL further analyze the impact of insulation placement, validated through experimental data. Results indicate that while internal insulation does not match the performance of external insulation, it can still significantly reduce energy losses, making it a practical solution for constrained settings. Future research will refine assessments for non-continuous insulation and explore additional wall configurations.