The energy consumption increase in a whole world considers as a warning about the depletion of resources and also increasing the negative impact on the environment (global warming, climate change, thermal island phenomenon, etc.). Where the building consumes 40% of total energy and produces 30% of the world's CO2 emissions. [1]
The thermal performance of the building's envelope (Walls – Opening – Ceiling – Flooring) is also considers as a serious problem because it works to consume energy to achieve the requirements of thermal comfort inside the buildings. The thermal loss of single-storey buildings is estimated about 45% of walls and outside windows, 42% of surface and ground and 13% of air leakage. While the thermal loss in the multi-storey building (5 floors) is estimated about 70% of the walls and outside windows, 13% of the surface and ground and 17% of the air leakage. [2] As a result, the exterior of the building is one of the most important factors affecting the thermal comfort and energy efficiency of residential buildings according to the Solar Radiation.
Therefore, the efficiency of energy consumption in residential buildings is one of the new trends that the world is currently heading towards where the building can achieve energy efficiency through the treatment of the external walls of residential units as one of the components of the building envelope in accordance with the requirements of the Egyptian code and the principles of environmental design.
The aim of this study is studying the effect of external wall thickness as a component of the building envelope in achieving efficiency of energy consumption and increase the comfort of residential units in the 6th of October City one which considers as a one of new city that allows to create new residential projects (unit with one direction). This effect is examined in the following directions: East - West - South.
The methodology includes reviewing the literature and methods that used to address the external envelope of residential buildings to achieve energy efficiency. A practical study was carried out by simulating a housing unit to inherit the effect of external wall thickness as a component of the external casing of a single-oriented residential unit in the 6th of October city in the directions (south – east - west) on the efficiency of energy consumption. The change in thickness of the wall from 12 cm to 25 cm in the south direction reduced the energy consumption by 13.13% and in the case of the use of double wall thickness of 12 cm with 10 cm air cavity 17.2%, while in the east direction the reduction in energy consumption at 25 cm was 14.33% while in the case of using a double wall thickness of 12 cm with 10 cm air cavity 18.65%, and finally in the case of west direction, the reduction in energy consumption at the thickness of 25 cm 15.26%, while in the case of a double wall thickness of 12 cm with a cavity of 10 cm 22.79%. Then the research concludes with some recommendations on how to reduce energy consumption by 46% and improve thermal performance in residential buildings by building envelope treatment not only by the thickness of the wall but also by the material of the wall, type of glazing, and covering the ceiling in case of exposed to the solar radiation.