The gradual reduction in buildings’ energy demand has led to an increase in the requirement for insulation. In the past, many buildings were insulated using external thermal insulation component systems (ETICS). However, these structures no longer meet current requirements and will require further renovation in the near future. One option is to add additional insulation to an existing ETICS system. This paper presents a case study exploring the implications of such a modification in the Central European region, with a particular focus on changes to the moisture regime of insulated walls. The study is based on heat, air and moisture (HAM) modelling. It also explores how the climatic load on structures is evolving in the context of global climate change, as outlined in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. HAM simulations were performed using meteorological data for various climate change scenarios. The aim is to determine the effect of the aforementioned changes on the climatic loads of a given type of building component in the Central European region.