Energy consumption in the building sector is clearly an important factor in the total energy bill, and it continues to increase. Cooling and heating in buildings are techniques used to condition their environments, research and development of natural methods for this conditioning are assumed to increase the importance in modern building in order to bring about savings in energy. Depletion of the world fossil fuel reserves and price uncertainty has forced many countries to turn to alternative energy sources to meet their needs. Like many other countries, Iraq, despite its oil wealth, must take steps in studying and utilizing alternative energy sources. Solar energy is one of the potential alternative energy sources, is particularly attractive because it is renewable, nonpolluting and widely available on-site. Solar energy is being used for many purposes, such as electricity generation, refrigeration and air-conditioning applications. Solar chimneys are one kind of renewable energy technologies, which enhance the natural ventilation of buildings.