Ceiling fan
A ceiling fan is a mechanical fan mounted on the ceiling of a room or space, usually electrically powered, suspended from the ceiling of a room, that uses hub-mounted rotating blades to circulate air. Ceiling fans typically rotate more slowly than other types of circulating fans, such as electric desk fans. They cool people effectively by introducing slow movement into the otherwise still, hot air of a room. Fans never actually cool air, unlike air-conditioning equipment, they in fact heat the air due to the waste heat from the motor and friction, but use significantly less power (cooling air is thermodynamically expensive). Conversely, a ceiling fan can also be used to reduce the stratification of warm air in a room by forcing it down to affect both occupants' sensations and thermostat readings, thereby improving climate control energy efficiency.
Solar-powered fan
It is similar to the roof mounted solar fan, except that its installation is a little different. Most attic fans are installed on the roof surface, whereas gable fans are installed in the gables, inside the attic and behind an existing louvered gable vent as the name suggests. They are mostly installed in places like greenhouse, cabin, RV's garages or barns and other storage places where heat and moisture are usually present. These types of fans are generally installed behind intake grills to provide ventilation. Gable Solar Fans are usually installed high on the gable close to the ridge and are also coupled with soffit or roof vents for well-balanced intake and exhaust air avenues. The airflow depends upon the level of sunlight when there is more sunlight, the airflow will be more resulting in enhanced cooling. It is also capable of lowering the air conditioning costs by cooling the attic.