*4.2.2 Changes in the practical world*

Observing recent trends in housing-related technology and systems, we have found noticeable changes, mainly in thermal insulation performance. Japanese housing thermal performance has been gradually improving, due to progress in technology and requirements for energy saving and occupants' health. As a result, recently, a new national voluntary system, the "net-zero energy house (ZEH) certification standards," has emerged and shown higher thermal performance criteria than usual criteria [16]. Recognizing these changes, we have lifted the desired value of "thermal insulation performance" of the two material elements: "thermal insulation" and "windows and doors." To be concrete, we have revised the desired value from the highest level in the JHPIS's thermal insulation performance grades to the relevant criterion stipulated in the ZEH certification standards.

#### *4.2.3 Feedback from the users*

After finding a constructive opinion in recent feedback from the system users, we have determined to include it in the latest revision. This opinion's gist is that lighting fixtures utilized in living spaces should be products with brightness and color adjustment functions, for energy conservation and residents' health. The necessary brightness of indoor artificial lighting changes depending on circumstances, including residents' visual comfort and natural lighting through windows. Meanwhile, exposure to bright lights and blue light before bedtime suppresses melatonin secretion and can affect sleep and potentially cause diseases [17, 18]. Accordingly, especially in living spaces, lighting fixtures fitted with brightness and color adjustment functions are beneficial for energy conservation and residents' health. Therefore, when revising the guidelines this time, we have added an explanatory note to "LED," the desired value of lighting fixtures' type, saying "lighting fixtures used in the living spaces are fitted with brightness and color adjustment functions."

Finally, all of the above revision items have been incorporated into the table of the "element-variable-desired value" framework. The final revised version of the guidelines has been shown in **Table 3** in our latest study results, "Comprehensive

strategy for sustainable housing design." Extracts from this latest revised version are demonstrated in **Table 3**. The added and modified descriptions in the latest

This section outlines how to produce sustainable design guidelines for the whole city. **Figure 4** shows the process of producing and revising sustainable urban design guidelines. This diagram has been drawn based on **Figure 3** in Section 3. First, the descriptions of "relevant structures" in **Figure 3** have been replaced with "cities" or "urban." Moreover, three items have been added to the box of "Determination of elements, variables, and their desired values in the design guidelines and checklist."

**5.1 Problems related to cities and requirements for sustainable urban design**

As shown in the upper central part of **Figure 4**, producing the design guidelines starts with identifying environmental, social, and economic problems related to

revision are written in *italics*.

*How to Design Sustainable Structures*

*DOI: http://dx.doi.org/10.5772/intechopen.95012*

*5.1.1 Problems related to cities*

**Figure 4.**

**287**

*Process of producing and revising the sustainable urban design guidelines.*

**5. Sustainable urban design guidelines**


(2) JHPIS means the Japan Housing Performance Indication Standards (for new homes).

(3) CASBEE means CASBEE for Detached Houses (for new construction) – Technical Manual 2018 Edition.

#### **Table 3.**

*The latest revised version of the sustainable housing design guidelines [extracts] [12].*

Finally, all of the above revision items have been incorporated into the table of the "element-variable-desired value" framework. The final revised version of the guidelines has been shown in **Table 3** in our latest study results, "Comprehensive

Durability JHPIS 3.1: Grade 3

Lighting fixtures Type of light LED *(lighting fixtures used in the living spaces*

*Storage battery Type Stationary battery or electric vehicle battery*

*Type of kitchen Open or semi-open*

Areas in the home Placing them closer

Width 75 cm or more

(2) JHPIS means the Japan Housing Performance Indication Standards (for new homes).

*The latest revised version of the sustainable housing design guidelines [extracts] [12].*

(1) Material elements are from "framework" to "storage battery;" spatial elements are from "specified

(3) CASBEE means CASBEE for Detached Houses (for new construction) – Technical Manual 2018 Edition.

Natural ventilation CASBEE QH1 1.2.1: Level 5

Materials CASBEE LRH2 1.1: Level 4 or over

Sunlight adjustment capability CASBEE QH1 1.1.2: Level 4 or over

*ZEH certification*

With shutters

*functions)*

*Linkage Interconnection with the home electrical system*

*Place in the home Between the entrance and private room area*

*Place(s) in the home In or near the living/dining room and kitchen area*

Accessible without steps

(Bath: 60 cm or more)

40% or more

Harnessed natural energy 100% or more of the total energy usage

*Thermal performance criteria stipulated in the net zero energy house (ZEH) certification*

*Thermal performance criteria stipulated in the*

*are fitted with brightness and color adjustment*

Fire resistance (outer wall) JHPIS 2–6: Grade 3 or over Shape and color Consideration for the landscape

**Element Variable Desired value**

Exterior

(outer wall, roof, etc.)

Equipment for harnessing natural

Specified bedroom (Bedroom for elderly and wheelchair users)

*Living/dining room and*

*Area(s) for working and learning*

Areas relating to water use and hot-water

Position and area of

bedroom" to "garden area."

*kitchen area*

supply

windows

**Table 3.**

**286**

energy

Thermal insulation Thermal insulation

*Environmental Issues and Sustainable Development*

Windows and doors Thermal insulation

performance

performance

impacts

entrance

Protection of glass against

Piping Measures for maintenance JHPIS 4.1: Grade 3

Routes to toilet and bath area, dining room, kitchen, and

Doorways Differences in level No differences

Garden area Ratio of the garden area to the exterior area

Framework Resistance to earthquakes JHPIS 1–1: Grade 2 or over

strategy for sustainable housing design." Extracts from this latest revised version are demonstrated in **Table 3**. The added and modified descriptions in the latest revision are written in *italics*.
