This paper investigates the performance of high-loft thermal insulations in terms of their compression properties, recovery behavior and thermal resistance. The aforementioned properties belong to the basic producer requirements for winter functional sportswear, sleeping bags or blankets. Majority of thermal insulation producers declare high quality of their products claiming durability and insulation within beginning of their application. But, it is important to uncover how dynamic compressive loading (which simulates real condition of using) influences heat transport of tested filling for the whole lifetime period. Therefore, two groups of top synthetic thermal insulation materials were tested before and after compression loading. Subsequently, relaxation behavior of samples was determined by thickness recovery after the compression test. Furthermore, thermal resistance was measured before and after the compression test to find out the change in thermal effectivity of samples. In summary, these results have not met expectations and show a rather poor correlation between the rate of compression after dynamic loading and the drop of thermal resistance of tested fillings.