A rough starting point
As a very rough guide, many installers start with about 1 ton for a small bedroom, 1.5 ton for a normal bedroom or small lounge, and 2 ton for a large lounge. These are starting points, not rules: your actual room can need more or less.
What makes a room need more
- Top floor under a roof that gets full sun
- Big windows facing west or south
- Many people, or a kitchen or open lounge joined to it
- High ceilings or poor insulation
Why the wrong size costs you
Too small and the AC runs flat out all day without ever cooling the room properly. Too big and a non-inverter AC switches on and off too often, which feels uneven and doesn't remove humidity well. Either way you pay more than you need to.
Ask before you buy
Tell the mistri or shop your room's length and width, which floor it is on and how much sun it gets. A good installer will also check where the outdoor unit can go and how long the pipe will be, which affects both cooling and installation cost.