In a transition from an industrial (material-based) toward a post-industrial service based economy (dematerialised), an increasing share in the total energy demand is originating from IT appliances (8% of total electricity consumption in EU in 2009). Users' behaviour is an inexplored source of potential savings that may reach 20%. In this study, users were identified as being part of one of three user typologies: normal, economic and optimal user and their behaviour observed. A complement of information about opinions and attitude was collected by means of a sociological survey. Results have been examined from the point of view of their usefulness as an input into Socio MARKAL model scenarios.