Fans use less electricity than air conditioners that run with compressors and are an economic way of cooling a house or a room. How effective a fan is at cooling depends on the speed of the air leaving the fan and on the climate you are in. In dryer climates, for example, evaporating water can help cool the air.
High Velocity Fans
Keeping the air circulating is a simple way to cool down. Although it won't feel quite like air conditioning, a high velocity fan will help reduce the heat. In the house you can point the fan upwards to circulate the air around the house and create a steady breeze. This will make it feel a bit cooler.
Evaporative coolers (sometimes called swamp coolers) work by cooling the air with evaporating water. Water is pumped or sprayed onto a breathable material and air is sucked through the wet material. The evaporating water cools the air passing through it. Essentially these units are a combination fan and water pump and can cool the air very well. However, they only work well in dry climates. In areas with high humidity, the water will not evaporate quickly enough to cool the air.
Some fans produce a fine mist of water that blows outward with the air. The cold water makes the air feel cooler and as the water evaporates it will cool even more. These work best outside. If used inside, they can make the room very wet which may damage paint, floors and furniture.
Attic fans are mounted on the roof inside an attic or the top level of the house. They work by drawing hot air upward out of the house and bringing cool air from the basement or lowest floor through the house. Usually, you have to open a window in the basement to allow the cool air to be drawn upward.