Résumé
We numerically performed the influence of moisture, external temperature and the type of concrete on the energy provided for buildings heating. The coefficient of diffusion is not taken as a constant. We developed a technique based on DOPRI5 fourth-and-fifth-order Runge-Kutta variable step integrator. Investigations were conducted in the range of -5: 20℃, which cover the majority of thermal conditions in which people live. As a result, energy consumption increased both with the increasing level of moisture content and with the decreasing level of the external temperature. For instance, in the case or normal concrete, when the outside temperature was T<sub>1</sub>= 15℃, the power of building heating was 30W/m<sup>2</sup> and when it was T<sub>1</sub>= -5℃, the power of building heating became 175W/m<sup>2</sup>. We have found that the presence of moisture induces additional energy expenditures. Two different types of concrete were involved in this study, namely normal concrete and pumice concrete. For an outdoor temperature of -5℃, the required heating power was 175W/m<sup>2</sup> in the case of a normal concrete wall. On the other hand, we needed only about 87.7W/m<sup>2</sup> when the wall was made of pumice concrete, showing that energy expenditure for pumice concrete was half that of normal concrete.