Salt hydrates, one of the categories of inorganic phase change materials (PCMs), have huge potential to latent heat or thermal energy storage in buildings energy management applications. But their energy storage performance seems not to be impeccable, due to the problems related to phase segregation, supercooling, and formation of lower salt hydrates. To resolve these issues, it is evident that detailed studies related to fundamentals of salt hydrate crystallization either from solution or melt are required in the presence of various additives that form a composite PCM. The current work details, preparation of homogeneously mixed salt hydrate Na2SO4 center dot 10H(2)O in laponite-based gel as a composite PCM. Studies and results related to minimized phase segregation and supercooling by introducing materials like open-pore polyurethane (PU) foam and/or inorganic borax will be discussed. By utilizing experimentally driven optimum quantities for novel composite PCM materials, PU-saltPCM (salt hydrate alone incorporated in PU foam), and PU-gelPCM (gel-based composite salt hydrate incorporated in PU foam), thermal performance studies were carried in a model system. The thermal performance results for both PU-saltPCM and PU-gelPCM composites as an insulation layer in the temperature range between 10 degrees C and 40 degrees C are discussed in detail.