Use Ceiling Fans Efficiently
Circulating fans include ceiling fans, table fans, floor fans, and fans mounted to poles or walls. These fans create a wind chill effect that will make you more comfortable in your home, even if it's also cooled by natural ventilation or air conditioning. Ceiling fans are considered the most effective of these types of fans, because they effectively circulate the air in a room to create a draft throughout the room. If you use air conditioning, a ceiling fan will allow you to raise the thermostat setting about 4°F with no reduction in comfort. In temperate climates, or during moderately hot weather, ceiling fans may allow you to avoid using your air conditioner altogether. Install a fan in each room that needs to be cooled during hot weather. Turn off ceiling fans when you leave a room; fans cool people, not rooms, by creating a wind chill effect.It's only cooling the body, so leaving a fan on when you're not in the room only wastes electricity. So, save more energy and remember to turn it (and any lights or electronics) off when leaving the room.
Referenced from: Energy.gov.