The research proposed thermal mass and thermal insulation materials, which are classified as passive solar techniquesin architecture, as a solution to limit the growth of buildings energy consumption in Egypt, and thus contribute effectively to solve our local chronic energy crisis. It shows how the thermal properties of the material can be used to differentiate between construction and finishing materials andto choose the suitable according to energy perspective, to achieve thermal comfort and reduce the using of electromechanical energy-consuming means at buildings following the instruction of “the Egyptian Energy code". The research follows the des criptive analytical method. It aims to demonstrate the efficiency andsuitability of this technique in our local environment compared to other passive solar alternatives, especially building running cost consideration andability to use it with already existing constructions which consist most of the current energy crisis problem in Egypt. It offers examples of materials that could be used in our local environment for new andexisting buildings.It explains cost and energy saving by using this system through a case study on an existing commercial building, uses a computer program to analyze thermal behavior with proposed materials and calculates the difference of running cost between two conditions.