**4. Conclusion**

This study showed how to design sustainable housing by employing the systemcontrol-based methods. Section 2 illustrated the methods with the two diagrams: (1) the control system for promoting sustainable housing design, (2) the process of producing and revising sustainable housing design guidelines. Using these methods, Section 3 demonstrated a concrete process of creating sustainable housing design guidelines. After identifying global and general problems related to homes, it specified requirements for sustainable housing design. Subsequently, these requirements were converted into a tabular form of "housing elements, variables, and their desired values." The completed table has turned out compact "sustainable housing design guidelines" for general use.

The proposed methods include four significant features: (1) totally visualized for promoting sustainable housing design, (2) user-friendly, (3) comprehensive, (4) flexible toward optimization. The first feature originates from the two diagrams shown in Section 2, namely **Figures 1** and **2**. These schematizations help understand the whole picture for promoting sustainable housing design.

The second characteristic, "user-friendly," results from the tabular form of "element-variable-desired value." Elements in the table are equivalent to actual parts of homes. Accordingly, system users can easily compare the design guidelines with actual homes or drawings. Meanwhile, the third characteristic, "comprehensive," originates in the understanding about sustainability and housing elements. As shown in **Figure 1**, we inclusively examined the sustainability conditions from

*Sustainable Housing Design: System Control Strategy DOI: http://dx.doi.org/10.5772/intechopen.100126*

two aspects: environment and well-being. Moreover, when selecting housing elements, we analyzed homes based on two fundamental factors: material and space. Consequently, the completed design guidelines could deal with various environmental, social, and economic issues, such as climate change, aging population, and workplace needs.

The fourth feature, "flexible toward optimization," results from the process of revising the design guidelines. As shown in **Figure 2**, the revision process has been created by combining the two aspects: (1) updates of related knowledge and information, (2) feedback from users. Through the updates of related knowledge and information, the system designers can adapt the design guidelines to deal with the changing necessities of the situation. On the other hand, the feedback loops help make the design guidelines more accurate and user-friendly. Therefore, repeatedly using that revision process enables the system designers to optimize the design guidelines to pursue sustainability.

Our future work includes further research and practice on sustainable housing design. First, following the revision process demonstrated in **Figure 2**, we are planning to revise the sustainable housing design guidelines for general use as well as those for use in Japan. Moreover, we must secure the coordination between the guidelines for housing design and urban design. Through such future work, we are aiming to refine the system-control-based methodology for sustainable design.
