The effective thermal conductivity of composites made up of VO2 (SiO2) spherical particles randomly distributed and embedded in a SiO2 (VO2) matrix are numerically studied in a range of temperatures around the metal-insulator transition of VO2. This is done by means of three-dimensional finite element simulations for different concentrations and sizes of the particles as well as various interface thermal resistances. Our results are validated against the Mori-Tanaka analytical model. In addition, we develop a numerical method to calculate the heat storage capacity for composites with VO2 particles dispersed into a SiO2 matrix. It is shown that: i) The effective thermal conductivity of VO2/SiO2 composites increases with the VO2 particles' size, while the one of SiO2/VO2 composites is pretty much independent of the SiO2 particles' radius. ii) At the VO2 transition temperature (342.5 K), the effective thermal conductivity of VO2/SiO2 composites increases significantly at a rate of 2.7 × 10−3 Wm−1K−2, such that its value doubles up the SiO2 matrix thermal conductivity at the particle concentration of 40.2%. By contrast, the effective thermal conductivity of SiO2/VO2 composites decreases at a rate of 8.6 × 10−3 Wm−1K−2. iii) The effective thermal conductivity is strongly affected by the thermal resistance in VO2/SiO2 composites, by contrast the resistance effect does not play an important role for particle volume fractions of SiO2 up to 34.1% in SiO2/VO2 composites. The Mori-Tanaka model and our simulations predict the same trend of the effective thermal conductivity values of VO2/SiO2 composites. However, the analytical model fails when the matrix is made up of VO2 and the volumetric fraction of SiO2 exceeds 34.1%. The latent heat storage capacity of VO2/SiO2 composites increases with the VO2 particles’ concentration, such that at 40.2%, it takes the value of 24553 J kg−1 (486.7 cal mol−1), which is about half that of the pure VO2.