Abstract
This study examines the thermal performance of buildings and the efficiency of alternative energy supply systems under cold climatic conditions, with a focus on Eastern Kazakhstan. The objective is to quantify the impact of building envelope insulation and energy system configuration on heating demand, primary energy consumption, carbon emissions, and economic performance. An analytical methodology based on standardized building physics approaches was applied to determine heat demand, accounting for transmission and ventilation losses as well as internal and solar heat gains. Climatic conditions were incorporated using the heating degree-day method. Several energy supply configurations, including conventional fossil-based systems and renewable-integrated solutions, were evaluated in terms of energy, environmental, and economic indicators. The results indicate that improving the insulation standard reduces the specific heating demand from approximately 185 kWh/m²·a to 63 kWh/m²·a, corresponding to a reduction exceeding 60%. Transmission losses represent about 70% of total heat losses. Primary energy consumption decreases from approximately 280 kWh/m²·a for coal-based systems to about 110 kWh/m²·a for renewable-based configurations. Similarly, carbon emissions are reduced from 0.34 kg/kWh to 0.04 kg/kWh. Systems with higher initial investment demonstrate improved life-cycle economic performance due to lower operating costs. The findings confirm that enhanced thermal insulation combined with efficient and low-carbon energy systems constitutes a key strategy for reducing energy demand and environmental impact in cold climate regions. The proposed analytical framework provides a consistent and reproducible basis for evaluating building energy performance and supporting energy planning decisions.