Using Portable Air Conditioning Units
Portable air conditioning units, while not offering the efficiency and cooling power of conventional central or window mounted air conditioning systems, can still be a workable alternative in some situations. Whether you need to simply rent a portable air conditioner for a party or other temporary need, or you're trying to determine the best unit to purchase for a workshop, garage, small apartment or bedroom space, or other application, you need to know the facts, advantages, and disadvantages of portable air conditioning units in order to decide on the unit that is best suited to your need.
First, the Disadvantages
Most users agree that portable air conditioning units just don't cool as efficiently as window units or central units. That being said, you need to know that it's very important to match the capacity of the unit to the size of the space you need to cool. Most portable air conditioning units start at about 7,500 BTUs of cooling capacity, which is enough to provide some cooling for a 150 square foot space. For larger spaces, a good rule of thumb is to add 1,000 to 1,500 BTUs for every 50 square feet. Even if you match the capacity to the space, however, don't expect the degree of cooling from a portable unit that you are accustomed to with a window or central system.
Since the unit is pulling air from within the same space it is cooling, it just won't get the air as cool as conventional systems. Next, be prepared for a higher noise level. Since all the machinery is in the space you're occupying—again, unlike window or central units—you're going to hear more of the noise. Especially with the smaller, more inexpensive units, operating noise can be a bit of a problem. You should take this into consideration, especially if you're using the unit in a bedroom.
Finally, portable air conditioning units work by condensing moisture from the air, just like window and central units. Unlike the latter, however, they can't just dump the excess moisture outside. Instead, you will either have to periodically empty a condensate pan or pass the unit's exhaust hose out the window (most units with an exhaust hose also come with a foam insulation kit to allow sealing the window opening).
Things to Look For
Portable air conditioning units do allow you to put some degree of cooling power in places where you otherwise wouldn't be able to. So, one thing you definitely want in a unit is—you guessed it—portability. Make sure your unit has good quality casters or wheels, because with the condensers and other equipment included, portable air conditioning units can be pretty heavy.