Performance Gap and Occupant Behavior in Building Retrofit: Focus on Dynamics of Change and Continuity in the Practice of Indoor Heating

Building retrofit is often reported to fail in achieving predicted energy savings; this mismatch in post-retrofit conditions is labeled the ‘energy performance gap’ and may be due to both occupant behavior and technical issues. In this study, the occupant is investigated through a case study of a recently retrofitted public housing in Milan inhabited by 500+ tenants. Informed by social practice theory and interviews to households, concurrent and interdependent elements in heating space are identified—including factors of comfort, competences involved and other interconnected practices. Patterns of continuity and change in setting thermal conditions in this retrofitted building emerge. In this respect, key dynamics of the occupants are related to rooted habits in managing heating, social norms of thermal comfort, mastered skills in dealing with technical devices and infrastructure and ways of organizing other routines such as laundry and forms of entertainment when services are limitedly accessible. The results inform plans for energy efficiency through building retrofit in which the integration of the social dimension and practices may contribute to maximizing the impact of the intervention and to limiting energy performance gap.