Choosing the right AC for a 100 sq ft room requires calculating the base heat load, considering ceiling height, and accounting for sun exposure.
For a standard 100 sq ft room with normal 10ft ceilings, a 1.0 Ton Air Conditioner is optimal.
An oversized AC will cool the room too fast without removing humidity (leaving you clammy), while an undersized AC will run continuously, skyrocketing your electricity bill.