The steadfast rotating fan has been employed to keep people cool since the eighteenth century, and it remains highly effective, requiring much less energy and providing more comfort than air-conditioning. Cooling people by increasing local airflow is at least ten times more energy efficient than refrigerating the air in a given space, and it also adds the benefit of a personally controlled thermal environment. If used in combination with air-conditioning, fans could lower energy use by 30-70%, even in incredibly hot climates or during heat waves. Circulating fans, which...