Here is a simple two-step formula you can use:
- Calculate the area of the room.
- Multiply the area by 150* watts.
For example, if your room is 6m by 5m:
- 6m x 5m = 30 m2
- 30 m2 x 150 watts = 4500 watts (4.5Kw)
*It’s also useful for us to know which direction the rooms face. Southerly facing rooms require less cooling in summer but more heating in winter. If the room is facing West, or if it faces North and has large windows, use a factor of 180 watts for your calculation. In our example above, a Westerly facing room would need a 5.4Kw system.
Use our Air Conditioner sizing tool.
Room and Air Conditioner Sizing Guide
If more than two people regularly occupy the room in daylight hours, add an extra 200 watts for each additional person.
Here’s a helpful hint to keep your running costs down: make sure the external compressor unit is shaded.