PV/T panels are innovative systems increasingly used in the building sector. As a matter of fact, in that context they allow a set of common problems to be addressed and often solved: lack of physical space and economic issues, always existing when PV and thermal panels are to be installed separately. Obviously, the main objective of PV/T panels is to enhance the electrical efficiency by cooling the PV cells, but the side positive effect is also the production of thermal energy, which can be suitably exploited with a proper configuration of the whole system and an appropriate design of its components. Their energy production and overall efficiency depend on several factors and therefore the effect of different system features should be investigated. In this work, a parametric analysis was performed to provide a contribution on this topic. The effects of the characteristics of the thermal storage on electrical and thermal system performances were analysed, also considering the influence of the thermal load magnitude. The conclusive considerations can be exploited by designers and researchers to maximize the efficiency of the systems in relation to the storage tank characteristics and both electrical and thermal loads. (c) 2020 Elsevier Ltd. All rights reserved.