The world is facing a huge energy crisis due to resources depletion. The renewable energies play a vital role in energy generation sector. Fossil fuels such as coal and oil cause enormous environmental pollution. Wind energy is a major renewable source of energy and can replace this fossil energy. This paper aims to study the energy generation methods using roof ventilators. A wind driven, having metallic construction and blades on its periphery is a roof top ventilator. It is installed on the roof of industries as well as machine shops, warehouse and it provide effective ventilation. Hot air becomes lighter and goes upward on the top of industries and is expelled out through ventilator. At the same time fresh air also suck inside due to free spinning of roof ventilator. This free spinning can be converted into electrical energy using different electrical components. This technique is low in cost and feasible because of the minimum quantity of transferring elements and electric systems.