can i make my paragraph any better ? etrofit existing buildings in order to raise energy efficiency is a highly important requirement, due to the need to reduce carbon dioxide emissions and improve energy performance in buildings, but the problem lies in existing buildings worldwide, as buildings are the main consumer of electrical energy, It represents approximately 60% of global energy consumption, and it’s also responsible for the emission of 33% of carbon dioxide (Co2) [1], therefore we need to develop buildings to maximize the utilization of ventilation and natural lighting and the exploitation of renewable energy resources. One of the modern technologies is Building Information Modeling, which the countries of the world seek to use in all stages of the building, starting from the design idea through operation, maintenance and demolition, because it saves time and provide cooperation for all departments, furthermore it provides accuracy of results and detection of clashes [2], therefore, the research will address the methodology of using (BIM) technology to improve and raise energy efficiency in existing buildings, through analysis of the administrative building of NASA Ames, and review of design and retrofitting stages of the building using BIM technology, which qualified the building to obtain the LEED platinum certificate, Using results of reviewing the building, retrofitting was applied to the administrative building of Suez Canal University as a case study for an existing building.