I purchased an LG LP0910WNR portable air conditioner. This type of air conditioner does not mount in the wall but instead rolls on the floor and the hot air is expelled to the outside through a 5 to 6 inch diameter flexible hose.
The problem is that while cool air is being blown out the upper front of the unit, the upper back and the hose are radiating heat. These two effects are fighting each other making the air conditioner very ineffective. Because of the radiant heating problem the room gets hotter and hotter until it is 95 degrees. Then the compressor turns off for about 3 minutes heating the room.
Then it turns on for about 4 minutes cooling the room. Then off for 3 and back on for 4, and it just keeps on going. Another problem is that since hot air has to go out the flexible hose to transfer heat to the outside, additional air has to be sucked out of the room into the air conditioner and out the hose. This means that unless you have an airtight room, air has to be sucked into the room from the outside.
The effect of all this is that the air conditioner is cooling part of the room and at the same time heating and humidifying (if the outside is humid) the rest of the room. This air conditioner is simply improperly designed.
Review about: Lg Electronics Air Conditioner.