 Abstract wood fibre is a great potential supportive material for creating a new composite known as phase change materials, PCM. This material has many beneficial qualities such as high sorption competency, low density, environmental friendliness, economic efficiency, and chemical inertness. The main goal of this research is to study the effect of using wood fibre mixed with stearic and capric acid eutectic mixtures on the fuel, cost, and carbon emission saving potentials for various PCM cases. It was found that the highest energy saving rate belonged to PCM5, which experienced a phase transition within the comfortable temperature range of buildings. This case resulted in a 52.7% energy saving for a thickness of 0.1 m. PCM1, PCM2, PCM3, and PCM4 also provided energy saving rates of 23.5%, 34.3%, 44.7%, and 50.5% respectively. Additionally, it was determined that the proposed composite provided a promising energy saving potential in building applications by reducing costs and emissions. This article was authored by Nubas Simfrahat, Abidu Steyoglu, Osman Jensal, and others. We are article.tv, links in the description below.