Validation of a polyurethane-based aerogel in practical use. Due to the increase of energy efficiency requirements for buildings, more efficient insulating materials are developed. The technology of aerogels achieves particularly low thermal conductivities with their pore sizes in the nanometer range. While aerogels can be manufactured from various materials, the behavior of a polyurethane-based aerogel under real conditions is analyzed in this article. The aerogel was installed in a wall element, the roof terrace and window connections of a building. With measurement data from one year of monitoring, the various applications were validated in hygrothermal simulation models.