The influence of temperature (in the interval of 300-400 K) and concentrations on the electrical conductivity, thermal conductivity, and thermoelectric power of copper chalcogenide-based crystals with the general formula (GeSe)_1 - _ x (CuAsSe_2)_ x has been considered. Heat transfer mechanisms have been determined. It has been found that the temperature dependence of thermal conductivity is nonmonotonic with a singularity at 358 K. Thermoelectric figure of merit ZT has been calculated.