Human-based energy retrofits in residential buildings: a cost-effective alternative to traditional physical strategies

Dynamic simulation is used in new buildings and renovations with the purpose to predict their thermal-energy performance, typically assuming a standard use of the buildings. Even if the role of occupants’ behavior is widely acknowledged to be a key factor influencing energy consumption in buildings, these predictive models are not used to quantify specific benefits deriving from precise occupants’ actions. In this work, a numerical–experimental campaign is carried out in a village of green buildings in central Italy, where the most innovative and efficient technologies are already implemented and, therefore, where further physical active or passive retrofits would not be cost-effective. This work demonstrates that, through a sophisticated theoretical–experimental modeling of a residential village, a substantial further energy saving is still to be achieved through zero-cost simple actions, i.e. human-based energy retrofits. Ordinary actions of energy waste reduction are described within the physical model with the final purpose to quantify the effect of occupancy operations considered at the same level of traditional physical retrofit scenarios. The combination of these human-based energy retrofits produces an annual personal primary energy saving of 239 kW h/person in the village, and a corresponding annual money saving of 84 €/person. This work shows that, when theoretical dynamic simulation models are performed in order to investigate buildings’ thermal-energy behavior and predict the cost-benefit efficacy of common physical energy retrofits, simple and effective human-based energy retrofits should be considered at the same level of physical retrofits, and even before them, for their intrinsic technical and economical efficacy.