The growth of urbanization in developing countries is a serious problem, because in general, developing countries are unable to accommodate the demand for housing caused by the increasing population who come to big cities to try their luck. According to Mahabir et. al. (2016), the inability of these developing countries, coupled with a lack of basic infrastructure and services for the community are increasingly becoming the reasons for slum areas or informal settlements to grow and develop.

One form of informal settlement in a city is Kampung. Kampung is a residential area in an urban area, which was built on its own initiative, which is characterized not only by its informality and illegality, but also by its flexibility and resilience (Tunas & Peresthu, 2010). The Kampung then emerged as an alternative to live for low-income people and migrants, who had difficulty getting housing at affordable prices. This condition can be seen in Kampung Cikini in the center of Jakarta. Based on the location, according to Ford (1993), Kampung Cikini categorized as inner city Kampung type, which allows access to greater job opportunities, resulting in migrants living here to seek fortune in big cities.

The existing building arrangements in Kampung Cikini create a unique spatial condition for its residents. In general, the Kampung’s land is not sufficient to accommodate all the inhabitants, leaving the residents living in a house that can’t be considered as a healthy house. In Kampung Cikini’s pattern, alleys that allow air to flow during the day are divided into two types. The first type is a 2 meters wide alley, which is covered by cantilevers of two 2-story houses on either side of the road. The cantilever left a small gap for sunlight to penetrate and illuminate the alley. Meanwhile, the second type is a 1 meter wide alley which is protected by a house’s cantilever on one side of the alley. Both sides of the alley are bordered by walls so that the alleyway is almost dark.

Seeing Kampung Cikini’s condition, sunlight is considered very difficult to find. In fact, sunlight plays an important role in human health, both mental and physical. According to Mead (2008), sunlight is useful for increasing consumption of vitamin D which is also beneficial for bone health. In addition, sunlight also functions to release serotonin and endorphin hormones, which are associated with a happier and calmer atmosphere. Therefore, most of the residents build their houses vertically and have a cantilever, apart from having limited land to get direct sunlight. However, this resulted in the alleys being blocked by cantilevers resulting in a lack of sunlight. As a result, we chose to redesign settlements in Kampung Cikini in order to help the residents maximize the sunlight entering their house so that the house and environment becomes healthier.

With limited sunshine, several strategies are needed in designing existing homes so that sunlight can be maximized properly. According to Lechner (2014), important things that must be considered in making a design strategy for daylighting are the orientation of the house, lighting from the roof, building’s form, space planning, color, and the use of different windows according to the functions, which are view and daylighting.

To create a house that maximizes the entry of sunlight, several different types of openings are placed in several areas, according to their function. Considering the context, we used several design strategies for daylighting, such as the use of skylights, light shelves, transom windows, blinds, and placing windows in the right places. The first strategy is to use skylights on the roof. With houses that are close to each other, even sharing walls, placing windows on either right or left sides of the house is impossible. Therefore, the residents felt the difficulties to get sunlight, especially in the deepest part of the house. Skylights are made to provide lighting for the innermost part of the house so that under the placement of the skylights, the second floor is made of voids so that sunlight can directly shine down to the first floor. The glass used for skylights is translucent glass, so that it can spread direct sunlight and become a very bright light source.

Transom window is also used above the door and windows as an additional access for the sunlight. The placement of the transom window is also added with the placement of light shelves to reflect sunlight that enters from the transom window, so that it can illuminate the room indirectly and not cause the inhabitants to feel dazzled. In addition, each window is equipped with blinds which allows residents to easily adjust the amount of sunlight entering the house and added privacy.

In order for areas that are often used by residents to get enough sunlight, the layout of the house is also very much considered and adjusted to the placement of the windows. For rooms that are used for residents' activities for a long period of time, such as bedrooms, living rooms and kitchens, it is certain to get enough sunlight. With the conditions of the residents of Kampung CIkini who are familiar and often interact with other neighbors, the family room which functions as a gathering space is placed in the front area of the house and efforts are made to get sunlight by placing windows.

In conclusion, applying passive design strategy in a house that responds to sunlight as a resource needed for human activities is the best and quite affordable alternative solution for settlers in Kampung Cikini who rely on renovating their homes vertically and pay less attention to lighting aspects.