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Air Conditioners Buying Guide

What size air conditioner do I need?

Finding the right air conditioner depends on numerous factors including: room size; ceiling height; insulation; size of windows; level of sunlight and more.

Here's our rough guide to the air conditioner capacity (size) you'll need for a particular room size.

Room size Capacity
Up to 20 sq m 2–2.5kW
20–40 sq m 2.5–5kW
40–60 sq m 4–6kW
60–80 sq m 5–7kW
80+ sq m 6–9kW

 Tip: Choose a model with equal or slightly greater capacity for the room. For example, if you calculate the room needs a 6kW model, it's probably a safer bet to get a model slightly above the required capacity than slightly below it, as a little extra grunt may help in extreme temperatures. But don't go too much above the required capacity.

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A proper calculation takes all the room's details into account:

  • The size of the room: length, width and height.
  • The type of room: living room, open-plan living room and kitchen, bedroom, etc.
  • The size and orientation of the windows and glass doors. A large north- or west-facing window can let in a lot of heat in summer.
  • Shading and curtains on the windows.
  • Insulation of the floor, ceiling, and walls.
  • The local climate.

Try the size calculator on by the Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH).