The utilisation of low-temperature heating systems has been demonstrated to enhance heat source efficiency and reduce energy consumption, thereby playing a crucial role in the conservation of building energy and the reduction of associated emissions. The present study investigates the application effects of radiator-based low-temperature heating technology across a range of building energy efficiency levels and climatic conditions. The objective of the study is to promote the adoption of low-temperature heat sources in heating systems and to support sustainable building practices. The TRNSYS simulation platform was utilised to develop building models representative of typical climate zones. The feasibility of radiator-based low-temperature heating was evaluated from the perspectives of thermal comfort (PMV index) and temperature stability, utilising scenario analysis methods. This evaluation encompassed various combinations of building envelope performance and radiator supply water temperatures. The findings indicate that enhancing the thermal performance of building envelopes can mitigate the impact of reduced heat dissipation during low-temperature water supply, thereby facilitating low-temperature heating (with water temperatures as low as 40°C) to meet thermal comfort requirements in energy-efficient buildings. In high-performance buildings, high-convection ratio radiators have been shown to maintain minimal temperature fluctuations. The findings of this research provide a theoretical foundation and practical guidance for the optimisation of heating systems in retrofitted buildings, the adaptation of low-temperature heat sources, and the selection of appropriate radiators. This research offers broad engineering application prospects.