Numerous insulating materials such as coatings have been developed and are commercially available. Hollow glass microspheres (HGMS) as well as fumed silica, despite their intrinsic properties, have received less attention in formulation of coatings. Here, we hypothesized the utilization of the fillers to evaluate and compare their effects on the insulating efficiency, mechanical response and surface adhesion of a class of micro-composites functioning as thin coatings. Polyester-based composite coatings were prepared using 0–30 wt% of HGMS and 0–12 wt% of fumed silica. The results confirmed the positive influence of the HGMS and fumed silica on the insulating performance of the fabricated coatings exhibiting around 20 % improvement compared to the pure polyester. It was shown that elastic response, impact resistance and the coatings/substrate strength are sensitive to the presence of fillers and are governed by the fillers type and loading as well as the interfacial restricted region and morphology of the composites.