Abstract Purpose – This paper investigates the effect of changes to fundamental components of concrete; cement type, water/cement ratio, aggregate size & age, on thermo-mechanical properties of hardened concrete. Understanding the heat transfer properties of construction materials will enable a reduction in energy expenditure and associated C02 emissions, contributing to a more sustainable built environment. Design/methodology/approach – Hardened concrete specimens were subject to steady state heat transfer test methods to determine thermal conductivity and specific heat values. Pore volume of specimens was determined using water displacement method and the compressive strength of specimens was tested according to procedures identified BS EN 12390 – 3 (2009). Findings – Cement type CEM I produced the lowest thermal conductivity values by a maximum of 30%, with the cement type group CEM I corresponding to higher pore volumes and lower densities than cement type group CEM II. Specific heat was found to be higher in cement types containing CEM II, with cement type being the dominant factor determining specific heat. W/c ratio 0.55 provided the lowest thermal conductivity values of the w/c ratio specimens, however w/c ratio was found to have no impact on the specific heat capacity of concrete. Cement type has been found to be the most dominant component of concrete on the properties tested. Originality/value – This paper presents knowledge of the thermal performance of concrete with easily achieved changes to concrete mix design, which can be used alone or combined for maximum effect, and their impact on compressive strength. The use of steady state heat transfer experimentation allows important thermal properties thermal conductivity and specific heat to be calculated.