The role of the occupant behavior in affecting the feasibility of energy refurbishment of residential buildings: Typical effective retrofits compromised by typical wrong habits

The necessity to predict building energy performance assumes a predominant role today. Present regulations in energy matter introduce pressing objectives for the energy requalification of buildings. Within spring 2020, EU Member States must adopt the European Directive 2018/844, which focuses the attention on present buildings. It establishes new obligations to retrofit the existing building stock. Solutions to improve building energy performance and to achieve economic, energy, and environmental benefits become mandatory, requiring robust and reliable procedures for energy modeling and simulation. The present study will show the importance of considering a non-standard occupant profile in energy performance simulations. The investigated edifice is a typical residential building in Naples (southern part of Italy, Mediterranean climate), built during the sixties and seventies. For the energy retrofit of the building, the most common refurbishment interventions in the Neapolitan building stock will be assessed for energy, economic and emissions savings, and thus new thermal insulation and replacement of windows. Firstly, the results will be analyzed by taking into account a standard-use profile of the occupants. Secondly, the possible wrong behaviors of users will be examined, to compare an “energy-intensive” model with the standard retrofitted model. The impact on building energy demand of the following actions will be analyzed: more energy-intensive use of the electric and lighting systems, the opening of the windows during the activation hours of the heating/cooling systems, the modification of the thermostat setpoint, the deactivation of the shading systems. The study shows a considerable increase in energy demand, following the wrong behavior of the occupants, which affects the economic convenience of the refurbishment investment. The energy retrofit is economically and energetically feasible for a standard building occupation, but sometimes wrong habits can reduce the convenience, if energy-intensive behaviors occur. This work will show that, when the numerical building model of a common building refurbishment is realized and when the cost-benefits analysis is performed, the uncertainty in occupant behavior cannot be neglected.