Do portable air conditioners have to be vented out a window?
Portable air conditioners typically come with three types of vents: side, back and bottom. Each type has its advantages and disadvantages when venting the unit outside your home. Since there is not a universal solution to this problem, you must choose which option works best for your situation. If none of these options work for you, consider installing a permanent central cooling system in your home instead of using a portable unit.
First Problem
Your first concern should be how much heat an ordinary household window puts into the room that contains the window. Most homes use old single-pane windows that lose quite a bit of heat through them. You may want to check to see if adding storm windows help prevent too much heat from leaving your home through the window.
If you have a central air system but want to use a portable air conditioner, it is good to install a permanent vent on the outside of the house with an outlet near where you plan to place the portable unit. This way, you can move the portable air conditioner from room to room as needed instead of having it exhaust out one single window in your home.
Other Options
If this option does not work for you because of space limitations, choose between using a back or side exhaust model. You also need to decide whether or not you will be permanently installing this device in just one area of your home, mainly those that are heated and cooled by central systems. There is no need to install a permanent vent outside the house in those cases because it will not be moved around much.
An important point to consider when placing your air conditioner unit is whether or not you are vented for gas heat. If you are, do not run certain portable air conditioners near gas lines. For example, if your home uses natural gas, the HFC-134a used in some air conditioners can form potentially explosive levels of carbon dioxide within ten feet of a leaking mainline. It should also be pointed out that some older natural gas systems may have piping with asbestos insulation which could pose a risk if disturbed during installation. Other precautions include placing vents for this unit up high on walls or ceilings where they are less likely to be damaged.