**8. Conclusion**

The current work raises the efficient sustainability of historical houses that can alleviate relying on fossil fuel and corresponding negative impacts. Keeping in mind the inclusiveness of the concept of sustainability, it can enhance the performance of Jedda's contemporary housing by considering the following:

Environmental issues: Shading in outdoor spaces and paths is a considerable objective; it can be provided by compact development which accordingly alleviate the impact of hot climate. Building configuration can also protect its envelop from overheating. Shading in open spaces and on buildings can be enhanced by projected masses. Likewise, enhancing air movement through the urban tissue is an effective way for creating comfortable outdoor spaces. Also, the natural ventilation for inner spaces of the houses can reduce air temperature and humidity. Passive tactics for

promoting shade and natural ventilation, like "*rawshan*" and air shafts, can be examined, simulated and efficiently developed. Too, paths width to height aspect ratio and orientation is a vital tool to control both shading and natural ventilation in outdoor spaces. Research identifies the direction of N-S, NW-SE, E-W as the most appropriate, in association with aspect ratio of 1/2.5.

With the abundance of contemporary building materials, some traditional materials, like "*Al-Mangabi*" stone, continue to prove their efficiency in meeting the harsh environmental conditions. Making use of the properties of such materials, especially the thermal resistance, can inevitably open the scope for more sustainable products and applications.

Rainwater harvesting from rooftops is a feasible approach that can alleviate relying on desalination and reduce the effect of urban flooding; both have serious environmental impacts.

Social issues: Local culture, customs and traditions and religious teachings are inherited in Arab communities and mostly reflected in historic houses. Privacy suggested hierarchical open space system with tiny areas for women and children, private entrance and separate section for women in the house, and special treatments for windows, openings as well as balustrade to protect the family from strangers' eyes. Hospitality advocated fancy gates and spacious reception room for guests. Humility promoted simplicity and abstraction.

Economic issues: Feasibility and economic vitality are a main driver for society. In the historic house, spaces were rationally tailored, flexibly used and incrementally extended to meet family needs. On the urban level, mixed use, and corresponding active trade movement, brought vitality and safety for outdoor spaces. Not contrasting with humility, ornamentation demonstrated the distinction of economic classes.

The discussion herein does not mean to replicate the historical houses but to benefit from sustainability values inherited in. Historical houses were formulated affected by several environmental, social and economic forces. It is important to understand which of these forces are still acting and which are vanishing. In contemporary housing, the reflection of continues forces can be developed in the light of present knowledge.
