The article is devoted to the development of vacuum insulation materials using non-traditional core materials based on natural or waste polymeric fibers. This article describes the results of research activities on this issue where test samples of insulation from primary or recycled cotton and polyester fibers obtained from textile recycling were tested. The objective was to verify the properties of the developed insulators under extremely low pressure and thus the possibilities of their potential use as core insulators in the vacuum insulating panels. On the basis of the results found on both core materials and prepared vacuum insulating panels, it can be stated that core materials based on primary and recycled polyester fibers represent a great promise for the future. By reducing the pressure in the structure of these insulators, thermal conductivity is reduced to the level typical of high-quality conventional core insulators (e.g. based on glass wool). These materials exhibited very good thermal insulation behaviour depending on pressure and time at same level as insulators based on glass wool. (C) 2019 Elsevier B.V. All rights reserved.