In this study, the incorporation of ethyl palmitate (EP) as a bio-based phase change material (BPCM) in wood particles, the preparation and properties of the novel biocomposite for building applications were investigated. The wood particle-based composites hosting BPCM were produced by cold compression moulding. The EP impregnation step was optimized in terms of uptake and its ratio by post-addition of non-impregnated fibers. The optimized wood particles/EP ratio were combined with 37.5% epoxidized linseed oil (ELO) as a binder to produce a composite with energy storage function containing more than 99% bio-ingredients. The optimum BPCM content in the composite was 25%. The produced biocomposites were characterized by T-hystory, DSC, TGA, and a moisture buffer test. The results revealed excellent moisture buffer values (2.07 g/m2 RH%) according to the Nordtest protocol, significant thermal mass, ability to store excessive energy in terms of latent heat and maintain the temperature constant for longer time, good thermal stability and improved specific heat capacity when compared to a reference composite without BPCM. The effect of incorporating BPCM into biocomposite for regulating temperature fluctuations was confirmed by comparing test prototype cubes, with and without BPCM, subjected to temperature fluctuation between 0 and 40 ◦C