Aircon sizing calculator.
Work out the right cooling capacity for a single room in seconds. Uses the residential heat-load formula our installers apply on quote day, adjusted for ceiling height, orientation, insulation, glazing and occupants.
Room details
Recommended size
For a 20.0 m² room, the closest standard model size is a 5 kW split system.
Heads-up: this is a residential heat-load estimator for a single room. Multi-head, ducted and commercial spaces need a room-by-room load calc — we do those on quote day.
How the calculation works
We start from a residential base heat-load of 150 W per m² of floor area for a standard 2.4 m ceiling in an average Melbourne home, then apply the following adjustments:
- Ceiling height — anything above 2.7 m increases the load by 5% per 0.3 m.
- Orientation — west-facing rooms take the afternoon sun and need +15% capacity.
- Insulation — an uninsulated ceiling or single-glazed windows add 10-20%.
- Occupants — every person above 2 adds ~120 W of body heat.
- Glazing — large expanses of glass (>20% wall area) add 10-25%.
The result is a recommended cooling capacity range. The lower end is the minimum that will cope with an average summer day; the upper end handles heat-wave conditions comfortably. Real-world quotes we produce take room-by-room measurements into account, so numbers may vary — send us the room and we’ll spec it exactly.
Want a properly-sized quote?
Send us the room dimensions — we’ll spec the exact model and price it fixed.