Selecting a windowless air conditioner as a cooling option is your best choice if you don't have central air and want a cooling system that doesn't block a window and allows you to open it for fresh air or access it as an emergency escape. Windowless air conditioners also allow more light to enter a room since and they make cleaning windows much easier since the panes aren't blocked. These types of air conditioners also work well in windowless rooms because they don't require ductwork to function.
Windowless Air Conditioning Basics
Windowless air conditioners function the same as other units except for the absence of ductwork. They use chemicals to transfer hot inside air to the outside air. These chemicals easily convert from liquid to gases and back again to liquids with the help of three main parts: a compressor, a condenser and an evaporator. Every type of air conditioner has these 3 parts.
The cooling process begins when the chemical first enters the compressor in the form of a gas. Gas pressure is increased in the compressor and then the gas enters the condenser. Here it cools significantly and turns to liquid again as it leaves the condenser. The liquid then enters the evaporator where it turns to gas again. As the liquid turns to gas, it takes on the heat from the air. The cooled air is then blown out through the air conditioner to cool the surrounding area. This process continues until the thermostat detects that the room is the temperature you set it to be.
Dealing With Condensation
Like every other air conditioner, windowless units produce condensation. With central air, this condensation typically goes down a basement drain. The condensation from window air conditioners usually falls outside. A windowless unit contains an internal water reservoir that either empties the condensation into a drip pan for easy removal, or can be connected to a hose to drip out a window or down a drain.
Venting a Windowless Air Conditioner
Unlike most units, windowless air conditioners don't need permanent installation. But they still require an exhaust tube to release the hot air created by increased gas pressure. If the unit isn't properly vented, it won't be able to properly cool a room. Most brands come with venting kits that allow you to vent it around a door, into an attic or drop ceiling. You also have the option to vent it through a casement window with a piece of Plexiglas. The glass only requires a 5-inch hole to vent the hose and it doesn't reduce the amount of light coming through a window.
Some units can be vented through a dryer vent, but manufacturer's typically discourage this. Most windowless air conditioners have an exhaust hose that's 5 inches wide. The standard dryer vent is only 4 inches. Even if the exhaust hose on the unit is 4 inches, the compressor is rarely strong enough to push the hot air through a dryer vent with standard flaps. If you do have a unit with a smaller exhaust hose and would prefer to vent it through your dryer vent, remove the flaps and cover the exterior opening with a screen instead.