Have you ever gone walking on a hot day and noticed that the temperature drops when you’re around a water source like a lake or stream? The kind of cooling that is happening in that scenario is the same kind used by an evaporative cooling machine, also called a swamp cooler. The evaporative cooler pulls hot air over wet evaporative cooling pads to bring down the temperature of the air.

Thanks to this water-based approach, an evaporative cooler also adds a little moisture to the air, like a humidifier, but the evaporative cooler actively uses the moisture to cool the air. This feature makes swamp coolers perfect for climates like the southwest that run hot and dry. Because the cooling effect is created through introducing the air to increased moisture, a swamp cooler will be less effective in climates that already have high humidity.

This water-based cooling strategy also sets this machine apart from AC units. While an AC unit is good at cooling fully sealable rooms and spaces, a swamp cooler can handle areas that experience airflow. In fact, you can even choose an outdoor evaporative cooler to use outside!

Most portable evaporative coolers require little to no installation. Just find a convenient place to plug your new machine, fill the water tank or tanks and turn it on. In terms of maintenance, it is important to clean and sanitize all water-related areas of a portable swamp cooler regularly to prevent the growth of mold, mildew or bacteria and to clear mineral buildup. To reduce mineral buildup, you can use filtered water, such as from a water filter pitcher, in your machine.

Many evaporative coolers include air filters to clean your air while cooling it. If you are particularly sensitive to airborne allergens, you can also invest in an air purifier to increase the number of impurities being removed from the air in your home.

Compared to AC units, evaporative coolers typically cost less, use less energy, and produce fewer emissions. This means you can save money up front and practice more sustainable living when you shop for a portable swamp cooler instead of choosing a portable air conditioner. The average swamp cooler is also quieter than the average portable, wall or window AC unit.