For a small room of 10 x 10 ft, the AC with 0.8 ton capacity is sufficient. But if the size of the room is around 150 sq. ft, you should fo for 1 ton AC. And if you are confused between window vs split ac, check the3 energy efficiency rating to calculate the electricity bill that you can afford to pay. Moreover, window ac is mostly installed at home and for office purpose, people use Split AC.