Electric roof ventilator An electric roof ventilator is a device installed on the roof of a building that is designed to improve ventilation and air circulation. The ventilator is powered by electricity and works by drawing hot or stale air out of the building and replacing it with fresh air from outside. Electric roof ventilators can be beneficial in a variety of settings, including homes, warehouses, factories, and other commercial buildings. They can help to reduce the temperature inside a building by venting hot air out, which can result in lower energy costs for cooling. In addition, they can help to remove humidity and moisture, which can be particularly important in spaces like bathrooms, kitchens, and basements.