Utilizing the Phase change material or PCM as thermal storage in solar research has been widely focused. Some researches embedded metal and non-metal Nanoparticles into the PCM to investigate the effect on the thermal properties of the mixtures. In this study, copper nanoparticles are dispersed into paraffin wax to form Nanoparticles-PCM mixture. Three samples have been prepared: Sample 1 is paraffin wax only, Sample 2 is 1 20nm copper powder + 150 ml paraffin wax, and Sample 3 is 2 20nm copper powder + 150 ml paraffin wax. Differential Scanning Calorimeter is used to analyse the melting point, solidification point and specific heat of mixture. Transmission Electron Microscopy is used to identify the shape and size of 20nm copper powder. The study showed that thermal conductivity of Nanoparticles-PCM mixture was increased as well as the sensible heat. However, there is reduction in the melting point and heat flow to melt the Nanomaterials but latent heat of fusion was increased. 20nm copper powder is proven to be suspended in the paraffin wax. © (2012) Trans Tech Publications, Switzerland.