In this work, polymethylmethacrylate(PMMA)/capric-stearic eutectic mixture (C-SEM) micro/nano capsules were synthesized effectively using emulsion polymerization method. POM and SEM analysis results showed that the synthesized PMMA/C-SEM micro/nano capsules were consisted with spherical shape with uniform structure. The PSD analysis indicated that the mean diameter of the capsules was 1.3 mu m and 28.1%-part of the capsules can be characterized as nano-sized spheres. DSC analysis exposed that the synthesized PMMA/C-SEM (1:2) micro/nano capsules has a melting temperature of 21.37 degrees C, which can be suitable for free cooling of buildings depending on the climatic conditions. It has a latent heat of melting of 116.25J/g, which can be enough to integrate with conventional building materials. TGA results exhibited that the thermal degradation temperature of the micro/nano capsules is very much higher its melting temperature. Moreover, the synthesized PMMA/C-SEM micro/nano capsules have good thermal reliability, chemical stability and thermal conductivity. By taking into consideration all results, it can be also concluded that the micro/nano encapsulated C-SEM can be used to fabricate new building components. (C) 2015 Elsevier B.V. All rights reserved.