Abstract Aerogel based insulation plaster has the potential to facilitate the thermal retrofit of historic buildings as its deployment can accommodate the requirements of historical preservation. Thereby, the thermal resistance of historical facades can be increased while maintaining their appearance. The present contribution includes the results of a long-term empirical examination of aerogel containing plaster systems especially for historic buildings under real conditions. In the course of this study, multiple test fields with aerogel insulation plaster were applied to the external walls of an existing room in a university building. Thereby different finishing coatings as well as variations with and without reinforcement mesh were considered. Over a period of three years, external and internal environmental parameters as well as hygro-thermal conditions (temperature, moisture concentration, heat flux) at multiple layers within the test fields were monitored. Moreover, the external appearance of the test fields was regularly captured via observation and photographic documentation. The measured data provided the basis to compare the actual thermal transmittance of the test fields with calculation results based on declared material properties. In addition, the results facilitate the comparison of the different solutions. Specifically, the results suggest a promising thermal performance level (in view of considerably lower U-values) as compared to conventional plaster products. Furthermore, the findings document the role of the finishing layer’s composition in view of the occurrence of potential cracks in the facade.