There are so many things to consider when buying a normal air conditioner. The questions only grow when you plan on buying or even looking at a rental portable air condition. Here are some basic guidelines from MovinCool.com that should help answer some questions:
How many BTUs do I need?
The first factor when calculating your BTU requirement is the size of the room. For portable units sometimes, it is best to do this based on the largest room in your home. If you don’t then when you do move from one room to another, any room larger than the capacity you have will cool too slowly. In most cases a vendor will assist you with the sizing necessary for your requirements, since they change based on operating environment like computer cooling.
How loud are portable a/c units?
This will largely depend on where you place the unit. Portable air conditioners are not as quiet as HVAC or window units as the actual cooling process happens internally. The quietest fall into the 50 to 59dBa range. Generally, if placed near vents or material that doesn’t reflect noise, the sound levels should not be an issue.
What sort of maintenance will be required?
As with any appliance, portable air conditioners also require maintenance to function problem free. The most basic of maintenance will be to clear out the water tank. In any cooling process moisture is generated. In a portable unit the moisture collects in a water tank that can be removed with a tray. This water needs to be taken out and emptied every so often. Some units use an evaporation method that requires external housing.