The mathematical model of a wood polymeric sand composite has been developed, which allows studying the thermal insulation properties of a composite material, taking into account the ratio of wood filler to the other components, the method for obtaining samples, and the type of wood filler. The technique of modeling and analysis of the obtained results is given. By mathematical modeling it was established that the wood polymeric sand composite has thermal insulation properties 2-3 times better than that of construction materials based on concrete. Construction materials based on the developed composite have a higher heat capacity than pure wood, which allows them to better maintain the constancy of the temperature inside the premises with significant daily fluctuations in the external temperature. A series of practical tests were conducted to evaluate the reliability of the results obtained. The discrepancy between theoretical and practical results does not exceed 5%.