In recent years, Italy has seen a rapid growth in the PV (photovoltaic) sector, following the introduction of the FIT (feed in tariff) scheme known as Conto Energia. In July 2013 the Italian government definitively cut FITs, leaving only tax benefits and a revised net metering scheme (known as "Scambio sul Posto") for new PV installations. In this scenario, the design of a new PV plant ensuring savings on electricity bills is strongly related to household electricity consumption patterns. This paper presents a high-resolution model of domestic electricity use. The model is based on Fuzzy Logic Inference System. Using as inputs patterns of active occupancy and typical domestic habits, the fuzzy model give as output the likelihood to start each appliance within the next minute. The model has been validated with electricity demand data recorded over the period of one year within 12 dwellings in the central east coast of Italy. The tool has been used to evaluate the self consumption percentage to correctly size a residential photovoltaic plant in a case study. A cost benefits analysis is presented to show the effectiveness of PV-generation in the new Italian scenario. (C) 2014 Elsevier Ltd. All rights reserved.