One of the first questions Aussie homeowners ask when researching solar is: “What size system should I install?”
The answer depends on your electricity usage, roof space, budget, and future plans. In Queensland and New South Wales, where sunshine is abundant, getting the size right can mean the difference between modest savings and a system that slashes your power bills for decades.
1. The Most Common System Size: 6.6 kW
– The 6.6 kW solar system is the most popular choice in Australia.
– It typically includes about 16–18 panels (depending on wattage).
– It produces around 25 kWh per day on average in QLD and NSW.
This size usually suits households with average energy use (15–25 kWh/day) and can cover most or all of the bill.
2. Bigger Systems for Bigger Savings
If you have more roof space or higher electricity demand, upsizing pays off:
– 10 kW system → ideal for large families, home offices, or anyone planning an EV. Produces ~40 kWh/day.
– 13 kW system → suitable for all-electric homes with pools, ducted aircon, or multiple EVs.
In many cases, the extra cost of a larger system is modest compared to the long-term extra savings.
3. Think About Your Usage Patterns
– Daytime-heavy usage (work from home, pool pumps, aircon running) → go larger, since you’ll use more of your solar directly.
– Night-time-heavy usage (work late, home at night) → pair with a battery or still go larger to export more power.
4. Plan for the Future
Solar is a 20–25 year investment, so don’t just size for today:
– Planning to buy an electric vehicle? Add at least 3–5 kW extra capacity.
– Switching from gas to all-electric appliances? Upsize to cover hot water, cooking, and heating.
It’s usually cheaper to install bigger now than to add panels later.
5. Roof Space Considerations
– A 6.6 kW system usually needs 30–35 m² of roof space.
– A 10 kW system needs ~50 m².
– Panels can be split across multiple roof sections (north, east, west) for better coverage.
If space is limited, consider high-efficiency panels (e.g. SunPower, REC, Longi).
Final Word
For most homes in QLD and NSW, 6.6 kW is the sweet spot — affordable, powerful, and big enough to wipe out most of your bill.
But if you’ve got the budget, roof space, or plans for an EV, go larger. With rebates still strong and electricity prices rising, installing the biggest system you can reasonably fit is usually the smartest choice.