Earth wall construction provides an opportunity for creating a model which could be applied in developed and developing countries, with a significant potential for reducing energy consumption in the 21st Century. The heat absorption and releasing properties of earth walls make them a good insulator because warming and cooling temperatures rarely penetrate through their full width. Earth wall construction projects which have demonstrated energy and environmental sustainability too often exist in isolation. Thermal mass gives earth walls their unique properties as a building material. Thermal mass is the amount of potential heat storage capacity available in a material. The main thrust of the earth architecture construction approach has been: the creation of rapid building procedures that largely eliminate the need for trade skills, relying mainly on the common sense and physical ability of local people. Perhaps the most important issue in connection with earth wall construction is the identification of favourable soils.