A process for determining an optimum range of compositions for a nanocomposite thermoelectric material system is provided. The process is performed for a nanocomposite thermoelectric material system having a first component and a second component made from nanoparticles. The process includes selecting a plurality of material compositions for a nanocomposite thermoelectric material system to be investigated and calculating a thermal conductivity value and calculating an electrical resistance value for each material composition selected. In addition, at least one Seebeck coefficient is determined for the material compositions selected. Then, a plurality of figure of merit values are calculated using the calculated plurality of thermal conductivity values, the calculated plurality of electrical resistivity values and the determined at least one Seebeck coefficient. After the plurality of figure of merit values are calculated, an optimum compositional range can be determined within which the largest ZT values may be exhibited.