Energy and Economic Savings Assessment of Energy Refurbishment Actions in Italian Residential Buildings: Comparison between Asset and Tailored Calculation

Abstract

Residential buildings have become one of the leading sectors in the energy refurbishment process towards the clean energy transition. Energy Performance Certificates (EPCs), based on the asset rating calculation method, are often used to quantify the energy performance in standard conditions before and after renovation, but their energy outcomes can significantly differ from the actual energy consumption and savings. More consistent results can be obtained by adopting a “tailored” approach, capable of considering more the actual building operation conditions and users’ behaviour. In this framework, the study evaluates the heating energy needs of Italian representative multi-family houses in all the climatic zones and five retrofitting scenarios with both asset and tailored ratings. Finally, a cost–benefit analysis, based on energy savings and interventions costs, is also carried out to assess the affordability of the refurbishment actions depending on the adopted calculation methods. The analysis of retrofitting scenarios highlighted that asset energy outcomes are generally slightly greater than the tailored ones (differences of around 3–13% on average), but the affordability of the chosen energy efficiency measures is significantly overrated. It could underline the need to adopt the tailored approach for more accurate energy savings assessment and economic evaluation.