Comparing Energy Improvements and Financial Costs of Retrofitting Interventions in a Historical Building

In Italy, energy improvements of historical buildings are one of the key aspects to reach the EU 2020 goals on energy efficiency. Many papers are available in literature to recover and retrofit historical buildings, considering different types of interventions aimed to increase energy efficiency in existing building. Considering the most common retrofit interventions in historical building, this paper focuses on the estimation of the energy improvements and related financial costs of four considered scenarios on the building envelope of the “pharmaceutical chemistry” historical building located in the Sapienza University Campus of Rome. Additionally, a cogeneration system and the installation of a PV system have been included among the considered scenarios, in order to analyze their energy performance jointly with feasible retrofitting interventions. Research methods included a dynamic simulation of building thermal loads in the current state and in the scenario after each considered intervention carried out using TRNSYS software. Furthermore, yearly savings, investment cost and payback periods have been evaluated for each considered scenario, taking into account both the purchase prices of the saved energy and the amounts needed to realize related retrofitting interventions. In conclusion, among the feasible interventions in historical buildings, the obtained results provide useful data about what strategy offers the best energy performance improvement if compared with its financial costs. Results could provide recommendations for other historical buildings that need retrofitting interventions for improving their energy efficiency.