I know using ceiling fans can reduce air conditioning costs, but are some models of fans more effective than others?
Ceiling fans are a point of common confusion. They don't actually cool a space, but by circulating air and evaporating moisture from your skin, they make you more comfortable at a warmer air temperature. If someone is normally comfortable at 75 degrees Fahrenheit, it's not uncommon for that person to be just as comfortable at 80 degrees with a ceiling fan operating. Some ceiling fans are more energy efficient than others. One of the best is the aerodynamically engineered Hampton Bay Gossamer Windward III product that, unfortunately, is only sold by Home Depot. When you leave a room, turn the ceiling fan off, since the heat from its motor will actually warm the space.
— Alex Wilson is the founder of Environmental Building News, publisher of the GreenSpec Directory of green building products, and two websites focused on green building: BuildingGreen.com and GreenBuildingAdvisor.com.