This article presents the results of experimental research on the impact of environmentally efficient materials developed on the basis of grey marl and sand with the addition of 3 % to 6 % of rice husk on the thermophysical characteristics: coefficient of thermal conductivity, specific heat capacity and thermal diffusivity. The thermal indicators are measured with a device based on the non-stationary method. The purpose of the research is to investigate the impact of a new type of a light natural organic additive material, the husk of rice grains, on the properties of the resulting composite. The task is to develop a new material which is both thermally efficient and eco-friendly. The results of the research show that the addition of rice husks reduces the coefficient of thermal conductivity by 42 %, of the thermal diffusivity by 38 %, and increases the specific heat capacity by 10 % compared to the reference sample.