The global building sector has demonstrated a massive increase in energy demand, which is contributed by the rapid economic progress, urbanisation, and improved living standards. Furthermore, a significant portion of this energy is consumed by the space cooling and heating processes through daily activities. In this study, the energy efficiency benefits of bio-phase change materials (BioPCMs) in improving the thermal insulation of Malaysian buildings were investigated. Additionally, the study aims to contribute to the sustainable development objectives. Malaysia has several abandoned palm and plantation oil sources, which can be studied as BioPCMs in the tropical climate environment. Furthermore, a heat flow metre was utilised to measure the thermal conductivity of concrete specimens. Based on the findings, an improved thermal expansion coefficient was determined between palm oil and vegetable oil ester. The palm oil thermal performance measured was 0.0983 W/mK, which was lower than vegetable oil (0.1031 W/mK). Resultantly, palm oil and vegetable oil are efficient BioPCMs in lowering thermal conductivity values and improving energy efficiency in tropical climate buildings. Thus, palm oil has demonstrated its suitability as a sustainable energy source for applications, such as cold storage, space applications, and transportation.