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This paper summarises the state of two research phases within the scope of the IEA Task 40 / Annex 52 "Towards Net Zero Energy Solar Buildings" [1]. The first objective is a cross section analysis of a comprehensive collection of more than 280 international zero energy buildings. The aim is to show trends, motives of actors, as well as their method to reach the zero energy balance. Secondly, an indepth study shows a rough analysis and characteristics of 50 exemplary Nets ZEBs from different countries and climate regions, as well as their combinations of measures concerning energy efficiency and renewable energy supply. It is shown that diverse actors with miscellaneous motives have lead to a lot of different building variations. Typical strategies can be assigned to the typology groups "small residential building", "apartment building" and "non residential building". Net ZEBs are much more energy efficient than average buildings which were built according to national construction and energy regulations. None of the leading Net ZEB examples exist without generation of PV electricity. Trends give an outlook of current and possible future combinations of technologies and passive measures for the realization of (future) net zero energy buildings.

Located in the French tropical Island of La Reunion in the Indian Ocean, the ENERPOS building was inaugurated in January 2009. The building is located in the Saint Pierre Campus of the University of Reunion Island. It was designed to be a net zeroenergy building with mixed-mode air-conditioning systems in some areas (natural ventilation, ceiling fans, air conditioning) and efficient passive solutions sets usually used in tropical areas -i.e. efficient solar protection coupled with cross natural ventilation. This article reports the results of a recent user survey of the staff and students who use the building, and relates the users' perceptions to some of the environmental control systems installed. Indications are that the users have been able to achieve thermally comfortable conditions for much of the year without recourse to the air-conditioning systems. However, there is still the need for more readily available information on how to get the best from the windows and the ceiling fan systems for the ever-changing groups of students, and staff who may only use the classrooms intermittently. For the more permanent staff group, preliminary indications are of improved health and productivity by comparison with their experience of other buildings.

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