Evaluation of Thermal Retrofit Variants for Facades in High-Rise Large-Panel Residential Buildings: Impact on Energy Demand Using the BESM Model

Abstract This article examines the effectiveness of secondary thermal retrofitting in high-rise buildings constructed using large-panel technology and presents a model for evaluating the efficiency of facade modernisation and aesthetic enhancement methods, with particular emphasis on their energy performance. Three retrofit variants were analysed: increased glazing of balconies, aluminium-clad balcony facades, and a fully glazed facade. Calculations were performed using Audytor software by Sankom, based on an energy audit and in-situ measurements, taking into account the U -value [W/(m 2 ·K)], annual energy demand EHV [kWh/m 2 ·year], cost C [€/m 2 ], and carbon footprint eCO 2 [kgCO 2 /(m 2 ·year)]. The results show that Variant 2 (V2) achieves the greatest energy consumption reduction (32.1%), while Variant 1 (V1) provides the best insulation performance ( U = 0.149 W/m 2 K) and the highest BESM index (1.109). Despite its higher cost (155 €/m²), V2 significantly improves both the building’s energy efficiency and aesthetics. Optimising thermal retrofit methods is a key factor in adapting large-panel buildings to contemporary standards and enhancing residents’ quality of life.