Window air conditioning units
Probably a bit less noisy that way, too.
[This message has been edited by k2 (edited June 25, 2003).]
As k2 explained, air conditioners just moves heat from the front evaporator (cooling) coil to the rear condenser where the outdoor air can remove it altogether. Keeping both sides inside the room would be like trying to cool a swimming pool by taking hot water out of the deep end and dumping in into the shallow.
There is also the heat generated by the fan motor and compressor which would actually cause the room to get hotter than before.
The Appliance Information Site
[This message has been edited by DanO (edited June 29, 2003).]