The portable air conditioners are console units that can be moved from room to room or other locations. However, they cost a bit more than window units and use more energy.

The small portable air conditioner is also called "windowless" air conditioners because technically you don't need a window: You can turn them on anywhere and they will produce cool air. Used this way, a portable a/c might make you feel a little cooler if you sit right in front of it, but in general it will not lower the temperature of a room much - unless used as described in bullet 1 in next seciton.

This is because while cool air blows out the front of the unit, hot air blows out the back or side. Normally you have the installed air conditioners in a wall so that they can blow out the hot air outside the house. Most people are also familiar with the water drain running from normal A/Cs used to transport the moist away. This is done because less moist air always feels colder than moist air at the same temperature.

Installation of portable room air conditioners
Unlike window air conditioners or central systems, portable air conditioners require very little installation and are easy to move around. The console units are usually 3 to 4 feet tall and 1 to 2 feet wide, and they roll around on small wheels or casters. They are made by such manufacturers as Delonghi, Fedders, Toyotomi, and Danby. Portable air conditioners offer a very versatile cooling option for those who can't use the more conventional air conditioning methods. They do have limitations, but none that can't be overcome.

1. Connect a vent hose.
As mentioned previously the hot air that dissapates from the air conditioner will be blown into the rooml. This can be overcome by connecting a vent hose to the portable air conditioner outlet and direct this hose out the window or into another room. Most models come with fittings that makes this hose hook-up easy.

2. Condensed water.
Some units simply come with a bucket to collect the condensed water from the portable a/c. Others are cleverly arranged with a small pump that circulates the condensed water over the unit's condenser where it evaporates and the hot air exits through the vent hose. This is a major advantage both in terms of convenience and the efficiency of the unit.

Where will a portable air conditioner be effective?

• Portable air conditioners are very effective in removing odors such as smoke, cooking and other undesirable indoor pollutants. Due to the fact that the portable a/c takes air from the room and blows it out of the room (for instance through a window) there will be an air drag from outside and adjecant rooms. This means that for example smoke in the room will not go to the other rooms but will actually get blown out the window as the room is gradually cooled.
  
  
• Portable air conditioners are ideal for cooling down small rooms such a small livingroom or a bedroom. Note that the coling capabilities are less than for a central air conditioner so big rooms and extremely hot rooms cannot be cooled effectively by a portable one. In that case a central air condioner is needed.
  
  
• Supplemental cooling. A portable air conditioner is very good to provide supplemental cooling. For instance in areas of a home or office that are served by a central system but still need cooling.
  In rooms with a high local heat dissipation the portable air conditioner is more efficient than a central air conditioner. This can be places with heat generating equipment such as photo copiers, computers, kitchens, laboratories etc. In such cases the exhausting of room air actually helps rather than hindering the cooling process.
  
  
• The one place where portable air conditioners can be more efficient than conventional models is a room with high "internal heat gain" -- meaning that most of the heat in the room comes from activities taking place in the room itself or from equipment used there. For instance in kitchens in homes or restaurants, offices with copiers and other heat-generating equipment, and computer centers or labs. In these cases the exhausting of room air actually helps rather than hinders the cooling process.

Generally speaking
Generally speaking a portable air conditioner will be a good supplement to central air conditioning in places mentioned right above. Also in cases where there is a need to move the "cooling effect" the moveable unit will offer an advantage. The central air conditioner will be more advantageous for large rooms and in cases where whole houses or apartments needs cooling. But though portable a/cs are less effective than central ones they offer a good cooling option for people where a central system is not possible to install. Further a portable airconditioner can be acquired for substantially less money than a central system.

Technical note: A cooling capacity (BTU) of 7,500 approximately corresponds to 250 square feet.