To know the appropriate size to purchase, you should first figure out the exact size of the area of the room where you want the split AC to be so that it should be able to cool the entire area in that room. A 1-ton split AC is ideal for cooling a room of size 80-100 sq. ft. On the other hand, a 1.5-ton AC is ideal to cool a room which is approx 120-150 sq. ft. And a 2-ton AC is perfect for cooling a room with a size of a maximum of 200 sq. ft.