Understanding the thermal conductivity of concrete is vital for enhancing energy efficiency and thermal comfort in buildings. This study aimed to investigate the relationship between coarse aggregate type and the concrete thermal conductivity at ambient and after subjected to elevated temperatures. Thermal conductivity was measured by analysing the temperature response to heat flow impulses. The results revealed a decreasing trend in thermal conductivity with rising temperatures, attributed to the expansion of air voids within the concrete structure, which improves insulation. Mixtures with quartz and andesite aggregates) exhibited higher thermal conductivity due to the superior heat transfer properties of these materials. Conversely, the mixture with expanded glass aggregate showed lower thermal conductivity, highlighting its insulating properties. Mixtures containing expanded clay and crushed clay bricks demonstrated intermediate thermal conductivity values. The findings underscore that the type of coarse aggregate significantly influences the thermal conductivity of concrete, with distinct differences observed across various aggregate compositions. This study contributes to a deeper understanding of how aggregate selection impacts the thermal performance of concrete, providing valuable insights for optimizing building materials for energy efficiency.