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How an Evaporative Cooling Fan Works

How An Evaporative Cooling Fan Works

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An evaporative cooling fan can lower the temperature of a room by five to 40 degrees. Different types of evaporative coolers and evaporative cooling fans exist at many different prices. They all work on the same basic premise: an evaporative cooler puts humidity into the air to lower the temperature.

Evaporative Cooling Fans / Misting Fans

The most basic model evaporative cooling fan makes an area feel up to 20 degrees cooler. This stand-up fan looks like any other portable mechanical fan someone may put in a house or office. Water blows through the fan blades to create a fine mist that lowers the ambient temperature. The fan’s hose hooks up to a regular indoor faucet or an outdoor hose spigot to provide a continuous stream of water.

Popular in picnic areas, theme parks and in backyards, these fans blow a mist of cool water into the air. This relatively inexpensive cooling option can cool an area of about 60 by 20 feet or more, depending on the size and power of the fan.

Portable Evaporative Cooler

A significant step up in both price and performance from a misting fan, a portable evaporative cooler can cool a small house. These energy-efficient cooling options work best in houses with open floor plans and few hallways. Experts rate evaporative coolers based on the cubic feet per minute (cfm) of cooled air they bring into a space. A 4,500 cfm portable unit, for instance, can cool an area up to 1,400 square feet.

Portable units often connect to a garden hose for permanent water flow. A small, electric-powered fan pulls hot, dry air into the unit from an open window and passes it over wet pads (pictured above). The water evaporates into the air. The fan blows the air into the room to cool it by as much as 40 degrees. Because evaporative coolers work by putting humidity into the air to cool down a room, they work best in dry environments.

Evaporative Cooling

Nearly equivalent to a central air conditioning unit in its cooling capabilities in dry climates, a rooftop down-flow evaporative cooler connects to a house’s ductwork and distributes cool air throughout the house.

Again, the evaporative cooler connects to a water source, which moistens pads located within the cooler. The hot, dry, outside air passes over the water pads and water evaporates into the air. Cool air blows into the house while warmer air exits the house through open windows.

It may take some experimentation to find the optimal amount to open windows; if windows are not open enough, condensation will form and the house will become too hot and swamp-like. If the windows are open too much, hot air will rush in, diminishing the cooling effect of the evaporative cooling fan.

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