The future of panel housing estates is influenced by a number of factors. Although panel housing estates have seen their share of commentary and analysis from both supporters and de-tractors, there has been no comprehensive effort to explore the field of panel housing estates in terms of building thermal regeneration measures. This article focuses on the links between thermo-technical regeneration measures in panel housing estates, and the application of External Thermal Insulation Composite Systems (ETICS) and their impact on the urban environment of panel housing estates. The paper contains three main sections in which we (1) synthesize the literature, sources, building physics context, and assumptions for the occurrence of biodeterization in the facades of prefab residential housing located in housing estates; (2) compare the case studies and their results from the 2010–2021 field reconnaissance, in situ diagnostics, and laboratory analyses; and (3) identify/illustrate common features, the extent to which the quality of prefab residential housing located in housing estates with ETICS exterior surfaces is influenced by the environmental context, whereby we understand the whole process of the environmental assessment framework as an interrelated complexity of the interacting links between the environment, urban planning, architecture and construction sectors, supporting a holistic approach to the issue at hand. The results show that regeneration work, on the one hand, improves the urbanized environment and the energy potential of a housing estate; on the other hand, we encounter new manifestations of defects and disorders in the form of biodegradation of facades that we did not expect.