The Libyan state has an ambitious strategic action plan for renewable energy. The plan aims to reduce dependence on the use of traditional energy sources to generate electricity and increase the penetration rate of electrical energy production from alternative sources to 20% by 2035. This research paper aims to study and evaluate the benefit that will achieved by solar water heating systems by saving electrical energy for 829 housing units in the residential complex of the Iron and Steel Factory in Misurata, Libya using the T*SOL_2021 analysis tool. Where the result showed that, when installing solar heaters on the roofs of residential floor units and on buildings in the residential complex of the Iron and Steel Factory, this will contribute to saving more than 2GWh of electrical energy annually, thus avoiding the emission of about 600 tons of carbon dioxide into the atmosphere. Keywords: solar energy, energy efficiency, solar water heating, solar heater, electric heater, carbon dioxide emissions