The global economy is at a turning point when the raw material is less and less about demand and harder to obtain. Moreover, the reduction of dioxide emissions carbon is mandatory in the context of climate change. At the same time, the waste in construction and other economic areas is increasingly difficult to manage because its sorting and recycling are not yet in line with the rules imposed by the European community and assumed by each state. In the current context of the need to reduce carbon dioxide emissions more and more, materials used for thermal protection of buildings must be obtained if possible from recyclable materials with low thermal conductivity and minimum energy consumption. In this paper, we propose a comparative analysis of the thermal conductivity obtained experimentally of some synthetic wood boards with variable content of recyclable waste (polystyrene, fly ash, sunflower husks, cement, polymer, etc ) using a double-climate chamber, with those obtained by numerical modeling using the finite element method. Experimental planning of synthetic wood boards was carried out with the help of the design of the experiment method which allowed a decrease in the number of experiments necessary for such investigations but with maximum efficiency on the results of the physicomechanical characteristics obtained. The results obtained by the two methods were very conclusive surrounding this material in the category of insulating ones with thermal conductivity between 0.071 and 0.107. We can say that synthetic wood obtained with variable addition of different compatible waste can contribute to more efficient use of this and implicitly to the decrease of the effect on the environment.