The main thing think about is to look for the amount of British Thermal Units (BTU) needed. A lot more BTU, far more cooling which are critical. One guideline that should be employed is as follows: if your room is 150 square feet, then came 7,500 BTU air conditioner will meet the requirements to cool the area. If there is double the space, 300 square feet, an ac with 10,000 BTU will get together the needs...