Retrofit Strategies Optimization Based on Indoor Comfort Analysis Under Real Conditions: The Case Study of the Secondary School ITC Carrara

The building sector has a significant potential for energy saving. At present, about 35% of the EU buildings are over 50 years old, and almost 75% of the building stock is energy inefficient. Therefore, school buildings represent a significant part of the existing building stock and a noteworthy part of total energy use. Throughout Europe, most school buildings were built between the 1950s and the 1970s and needed to be renovated, including the energy upgrade towards nearly zero energy building targets (nZEB). School buildings’ energy retrofit actions have to improve building design and the upgrade of energy systems and building components solutions and focus on the indoor environmental conditions for their occupants. Besides low energy consumption, efficient school buildings have many benefits from indoor comfort (thermal, visual, acoustic, and indoor air quality). Therefore, acting on the existing building stock implies understanding user needs to define adequate energy-saving strategies. This paper aims to present a method to define and assess retrofit strategies optimization of school buildings, developed in the frame of research Smart Skin Envelope, and based on users’ comfort analysis under real conditions. The research approach takes into account user preferences to evaluate energy-saving opportunities. The methodology consists of the thermal comfort assessment by combining physical environmental data monitoring through in-situ measurements and submitting subjective questionnaires to the occupants. Finally, the research work presents and evaluates the results of this experimentation applied on a school building (the secondary school Carrara) built in the 60 s and located in Lucca (Italy).