Products that cool the air without using an exhaust pipe include evaporative coolers and personal air coolers. While evaporative coolers are not touted as air conditioners, many are designed to cool a room. American Comfort, maker of the ACW1000 Personal Air Cooler, does bill its appliance as an air conditioner.
Also known as swamp coolers, evaporative coolers are geared to regions with low humidity, according to Ventless Portable Air Conditioners. The units cool the air in a room by evaporating moisture through a looseknit material which is kept wet by being partially immersed in a tank of water.
The ACW-100, on the other hand, combines the functions of a personal air conditioner, dehumidifier and air purifier, according to Compact Appliances. In contrast to an evaporative cooler, American Comfort's appliance is meant only for personal, spot cooling use in a small area of a room. The ACW-100 blows cool air out the front but hot air out the back, meaning that areas behind the unit are not cooled.
In an evaporative cooler, a fan inside the unit dries the air while creating a cooling breeze that can lower the temperature in the room by as much as 30 percent, as stated by Ventless Portable Air Conditioners. Since there is no refrigeration process for exchanging hot air for cold, there is no need for an exhaust pipe.
Manufacturers of evaporative coolers include Honeywell, Luma and NewAir, for example.
American Comfort claims that the ACW-100 also dehumidifies up to 30 pints of moisture daily. Features include a Bucket Full indicator light with auto-shutoff to guard against overflowing and a washable pre-filter aimed at removing large particles of pollution from the air.