Rusun is a simple flat categorized as Affordable Housing (AH), which means it requires economic energy efficiency and optimal Natural Ventilation (NV) to manifest and provide comfort for users. This research will review the effect of spatial configuration on NV conditions of Rusun unit in terms of the condition of wind flow (WF) and wind speed (WS) value in each residential room by simulation method.The condition of the unit is on the 10th floor and height of 31.5m with an outdoor WS of 1.62 m/s in three different space configurations. It was found from the simulation that residential space that has direct access from openings both inlet and exit (outlet) has a more optimal WF and WS. From the WF condition and WS value following the needs of residential user activities, it is expected to optimize NV in Rusun units and in line with that, can realize energy-efficient Rusun buildings in terms of occupancy.

Economic growth in ASEAN countries encourages significant urbanized growth. In line with the growth of urbanization, large swathes of residential buildings have been constructed in urban areas, especially, in the case of Indonesia, through the government's 1000 rusun (high-rise affordable housing) development program in Jakarta. In order to reduce energy consumption and create a sustainable rusun, a passive strategy is needed in the form of natural air conditioning through optimized natural ventilation in these buildings. In this study, testing was conducted on Rusun Rorotan in Jakarta, from two wind source directions (north and northwest) with five void decks configuration samples each, in order to determine wind flow and wind speed patterns in the Rusun area. For this purpose, the wind tunnel simulation method using the Butterfly plugin in Grasshopper was employed. T These results should provide a reference for future residential property developers, especially in the scope of other countries in ASEAN, which have similar climatic conditions to that of Indonesia.