This study concerns the determination of empirical evidence of a real estate market premium for Green Buildings and of an aware role of the private real estate market as driver to foster-up urban and architectural sustainability and energy efficiency. In real estate markets, there is growing relevance of Green Buildings, especially in cities where the greater part of residential buildings is built before the first regulations on energy performance. Through policies oriented towards sustainable practices, a twofold goal can be achieved: energy consumption mitigation respecting the historical value for existing buildings, direct economic impacts on real estate values. In some metropolitan or urban contexts, the “green premium” for buildings can be understood as a real “gold premium”. This result has been highlighted and quantified with a real estate market analysis developed for a central area of an Italian mid-size city, pursued through the innovative tool of Evolutionary Polynomial Regression (EPR). The study highlighted a higher sale price for properties characterized by the best ecological characteristics and energy efficiency (+41.52%).
The world’s existing buildings are aged, in a state of deterioration and in need of interventions. When selecting the type of possible intervention to be applied, the choice falls between two alternatives: simple unsustainable ordinary maintenance versus ecological retrofitting i.e., an increase in the quality of the indoor environment and building energy saving using local bio-natural materials and products. The present research seeks to respond to the requests of recent comprehensive reviews which ask for the retrofitting of the world’s huge existing building stocks and portfolios by proposing an approach and testing it in a specific case study (at the unit, building and urban block level) which can then be carried out and repeated in the future on a larger urban scale. The real-world experimentation in the provided case study achieved the important outcome and goal of a Green Building strategy and post-carbon city framework i.e., the significant enhancement of the thermal performance of the buildings as a result of a few targeted key external works and the consequent saving of energy in those already existing (but not preserved and not included in the state national register or record of monuments) Liberty-style constructions. All the above show that these important existing buildings can be ecologically retrofitted at an affordable cost, although initially slightly more expensive than the cost of ordinary unsustainable maintenance. However, this difference is offset by the favorable pay-back period, which is fast, acceptable and of short duration. The tried and tested approach, the positive proposed case study and the experimental database-GIS joint platform (the details of which can be found in an additional supplementary research which is currently being carried out) are the bases on which a future decision support system will be proposed. This support system can be carried out as a tailor- made solution for the ecological retrofitting of the enormous existing building stocks and portfolios which must be considered on a larger scale i.e., at ward, quartier, city, regional and country level.