Appraisal of Sustainable Retrofitting of Historical Settlements: Less than 60% Unexpected Outcomes

The present research aims to assess, from both ecological and economic perspectives, a strategic solution applied to the building sector that can contribute to mitigating the planetary tragedy of the overconsumption of global fossil energy (coal, oil, and gas) and, thus, climate change, along with its dramatic negative impacts on the planet, humanity, and the world’s economy. Buildings are the largest consumers of fossil fuel energy, significantly contributing to Greenhouse Gas (GHG) emissions and, consequently, to climate change. Reducing their environmental impact is therefore crucial for achieving global sustainability goals. Existing buildings, mostly the historical ones, represent a significant part of the global building stocks, which, for the most part, consist of buildings built more than 70 years ago, which are aged, in a state of deterioration, and in need of intervention. Recovering, renovating, and redeveloping existing and historical buildings could be a formidable instrument for improving the energy quality of the international and national building stocks. When selecting the type of possible interventions to be applied, there are two choices: simple and unsustainable ordinary maintenance versus ecological retrofitting, i.e., a quality increase in the indoor environment and building energy savings using local bio-natural materials. The success of the “Ecological Retrofitting” Strategy strongly relies on its economic and financial sustainability; therefore, the goal of this research is to underline and demonstrate the economic and ecological benefits of the ecological transition at the building level through an integrated valuation applied in a case study, located in Southern Italy. First, in order to demonstrate the ecological benefits of the proposed strategy, the latter was tested through a new energy assessment tool in an updated BIM platform; subsequently, an economic valuation was conducted, clearly demonstrating the cost-effectiveness of the building’s ecological transition. The real-world experiment through the proposed case study achieved important results and reached the goals of the “Ecological Retrofitting” Strategy in existing (but not preserved) liberty-style constructions. First of all, a significant improvement in the buildings’ thermal performance was achieved after some targeted interventions, resulting in energy savings; most importantly, the economic feasibility of the proposed strategy was demonstrated.