Calculate the right AC size for your space, fast and free.
Sizing Calculator
Free Sizing Guide
What Size Air Conditioner Do I Need
for My Room or Home?
Use this free air conditioner sizing calculator to get a quick kW recommendation for your room or home. If you are comparing full-home options, see our ducted air conditioning cost calculator, or if you want pricing for a wall-mounted unit, use our online split system quote.
For more detail on system running costs and energy labels in Australia, you can also read the Australian Government heating and cooling guide. When you are ready for tailored advice, book a free quote with Jay’s Air Conditioning Sydney.
Use this Sydney air conditioner sizing calculator as a starting point for choosing the right system capacity for your room, apartment or full home. If you already know the type of system you want, you can compare ducted air conditioning costs, request an online split system quote, or browse our air conditioning pricing and costs page for more guidance.
If your current unit is struggling, blowing weak airflow or not keeping up on hot Sydney days, it may be worth looking at air conditioning repairs in Sydney before replacing it. For tailored advice on sizing, installation and energy efficiency, you can also book a free quote with Jay’s Air Conditioning.
Sizing calculator
Adjust the inputs below. Your recommended capacity updates in real time.
Only count the rooms you want conditioned. Skip garages, bathrooms and laundry unless you plan to condition them.
Not sure? A typical 3-bed Sydney home is 130–170 m². A large 4-bed double-storey is 220–280 m².
Zone setup
Zoned ducted systems rarely run every zone at once — we size the unit for how you actually use it.
Most Sydney homes run 60–75% of zones simultaneously (e.g. 3 of 4 in the evening).
If it's a concrete-slab ceiling (apartment), select "Insulated".
Minimum capacity
Based on a 20 m² room on a split system.
Quick reference guide
A rough rule of thumb for common Sydney room sizes.
- Bedrooms
- Small study
- Small lounge
- Master bedroom
- Small kitchen/diner
- Home office
- Large lounge
- Large bedroom + ensuite
- Mid open-plan
- Large open plan
- Kitchen + dining + lounge
- Small shop / office
Questions about sizing
Questions about sizing
It uses the same heat-load method our installers use on first visit and lands within 10% for most Sydney homes. For very unusual spaces (double-height voids, glass houses, commercial), we’ll fine-tune on a site visit.
Air conditioners cool a volume of air, not an area. A 20 m² room with a 3.5 m ceiling has 30% more air to condition than one with a 2.4 m ceiling.
Zoned ducted systems don’t need capacity for every zone running at once. We ask how many zones you typically run simultaneously (e.g. 3 of 4 in the evening) and size the outdoor unit for that real-world usage — smaller unit, better efficiency, lower running cost.
No — oversized units short-cycle, use more power, don’t dehumidify properly and leave the room clammy. Right-sizing is the single biggest comfort decision.