Calculate the BTU or kilowatt (kW) cooling/heating capacity needed for your room. Based on Australian climate zones and NCC energy efficiency requirements.
| Item | Value |
|---|
| kW | BTU | Room size | Est. cost |
|---|---|---|---|
| 2.0 kW | ~6,800 | Up to 15 m² | $600–900 |
| 2.5 kW | ~8,500 | Up to 20 m² | $700–1,100 |
| 3.5 kW | ~12,000 | 20–30 m² | $900–1,500 |
| 5.0 kW | ~17,000 | 30–45 m² | $1,100–2,000 |
| 7.0 kW | ~24,000 | 45–65 m² | $1,500–2,800 |
| 9.0 kW | ~30,700 | 65–80 m² | $2,000–3,500 |
Reverse-cycle split systems are the most energy-efficient heating and cooling option in Australia. The Energy Rating Label (displayed on all appliances sold in Australia) shows star ratings and kWh consumption to help compare models.
The National Construction Code (NCC) divides Australia into 8 climate zones. Darwin (Zone 1) and Cairns (Zone 2) are hot-humid. Sydney (Zone 5), Melbourne (Zone 6), and Adelaide (Zone 5) are temperate. Hobart and alpine areas (Zones 7–8) are cool to cold.
Look for a high star rating (6+ stars) and a high COP (Coefficient of Performance). A 5.0 kW unit with COP of 4.0 produces 5 kW of cooling while consuming only 1.25 kW of electricity. The Energy Rating website (energyrating.gov.au) lists all rated products.