6kW Solar System Cost in Australia [2025 Guide]
Reviewed by Leigh McInerney
A 6kW and 6.6kW solar system in Australia costs between $5,200 and $8,800 in 2025 after federal rebates. It typically produces around 24–27 kilowatt-hours (kWh) of electricity per day, which is enough to cover the power needs of an average three to five-person household.
A 6.6kW solar system is the most popular size system in Australia by far and will produce sufficient power for the average Aussie home. The 15 panels required will fit on most roof layouts and the typical payback period of this system is 4 years.
Pro tip: Check other size system prices in our Solar System Cost Guide.
| Quality | Gross Cost | Net Cost (after rebates) | Example Brands |
|---|---|---|---|
| Budget | $8,000 - $9,000 | $5,200 – $6,000 | Jinko, Trina |
| Mid-tier | $9,500 – $11,000 | $6,500 – $7,200 | Canadian Solar, Q Cells |
| Premium | $12,000 – $13,500 | $7,800 – $8,800 | SunPower, REC |
Table of Contents
How Much Does a 6.6kW Solar System Cost in 2025?
6kW and 6.6kW solar system prices in Australia ranges between $5,200 and $8,800. The variation comes down to panel and inverter quality, installation complexity, and location.
Budget systems, typically using cheap solar panels like Jinko or Trina paired with a standard inverter, are priced on the lower end. Premium packages with SunPower or REC panels and high-efficiency inverters like Fronius or SolarEdge push toward the top of the scale.
Small-scale Technology Certificates (STCs), shave thousands off solar system prices. Without STCs, most systems would be priced $3,000–$4,000 higher. These incentives reduce slightly every year until they phase out in 2030, so waiting too long may cost more in the long run.
6.6kW vs 6kW Solar Systems – What’s the Difference?
Although many people search for both “6kW” and “6.6kW” systems, in practice, the 6.6kW is Australia’s most common residential size. The number comes from constructing a solar power system from popular 440 Watt solar panels.
15 x 440W panels = 6,600W or 6.6kW system. Alternatively is you used 15 x 400W panels, you would end up with a 6kW system. Different manufacturers create panels with varying outputs but they are much of a muchness.
An added bonus of this size system is most 5kW inverters can legally accept up to 6.6kW of panels under Clean Energy Council over-sizing rules. This is a big win as a 5kW solar system might be a little small, but just adding a few more panels, with the same 5kW inverter means bigger gains for very little extra investment.
Why 6.6kW Became the Standard
- Panel wattage has steadily increased, meaning you can now reach 6.6kW capacity with fewer panels.
- Over-sizing ensures you get more output during mornings and afternoons, when the sun is weaker.
- The cost difference between 6kW and 6.6kW is minimal, but the extra output significantly boosts savings.
Oversizing with a 5kW Inverter
A 5kW inverter matched with 6.6kW of panels generates more usable energy throughout the day. In many cases, the inverter clips only at peak midday sun for short periods, but the system still produces more power overall compared to a true 6kW setup.
Power Output of a 6.6kW Solar System
On average, a 6.6kW solar system produces between 24 and 27 kWh of electricity per day. How much electricity your system produces depends on your location, roof orientation, shading, and the time of year.
How Many Panels in a 6.6kW System?
A 6.6kW system requires between 15 and 20 panels, depending on the wattage of each module. Modern panels now produce 415–440 watts each, which means fewer panels are needed compared to older 250W modules
How Much Roof Space Do You Need?
| Panel Wattage | Number of Panels | Roof Space Required |
|---|---|---|
| 370W | 18 | ~36 m² |
| 415W | 16 | ~32 m² |
| 440W | 15 | ~30 m² |
Most Australian homes will need 30–40 square metres of usable roof space to fit a 6.6kW system. A north-facing roof is ideal, but east/west orientations also perform well with only a slight drop in daily production.
How Much Will a 6.6kW Solar System Save?
A 6.6kW solar system saves the average household between $1,800 and $2,400 per year. The exact figure depends on how much power you use during the day versus exporting back to the grid.
Self-consumption is key: if you run appliances during sunlight hours, you’ll save more. If most power is used at night, savings rely heavily on feed-in tariffs, which are declining in most states.
State-by-State 6.6kW Solar Prices in 2025
While federal rebates apply everywhere, final costs vary slightly by state due to labour rates, installer competition, and extra incentives.
| State | Average Price Range | Additional Incentives |
|---|---|---|
| NSW | $5,200 – $7,000 | Federal STCs only |
| VIC | $5,500 – $7,300 | VIC Solar Homes rebate |
| QLD | $5,100 – $6,800 | Federal STCs only |
| SA | $5,400 – $7,200 | SA battery rebate (optional) |
| WA | $5,300 – $7,100 | Federal STCs only |
| TAS | $5,800 – $7,500 | Federal STCs only |
Government Rebates for 6.6 kW Solar Systems in Australia
Government rebate incentives through the federal STC program, reduce the price of a 6.6 kW solar system by $2,155 (Zone 3) at the time of purchase, lowering the upfront cost of solar. This varies from city to city, but not by much.
The value changes depending on where you live — for example, a system in Melbourne may generate fewer certificates than one in Brisbane due to local energy production levels.
Because the rebate scales with system size, many households opt for this setup as it delivers solid energy usage coverage and keeps the price range within reach. It’s one of the reasons this system size has become so common across the country.
How much can rebates reduce the cost of a 6.6 kW system?
On average, rebates on a 6.6 kW solar system in Australia cut around $2,500–$3,500 from the total bill, making the payback period faster and more attractive. For a standard solar system using quality panels and inverter, the incentive often covers about a third of the installation.
Adding a Battery to a 6.6kW Solar System
A 6.6kW solar system with battery costs between $12,000 and $18,000. While this almost doubles the upfront price, it allows households to store excess solar for evening use and provides backup in blackouts.
6.6kW with Tesla Powerwall
- A 6kW or 6.6kW System with Tesla Powerwall 2 battery storage costs around $15,500–$16,500 fully installed.
- Adds 13.5 kWh of usable storage.
- Can cover most evening loads, including cooking and entertainment.
- Output capacity give you enough energy to power all household appliances at peak usage.
Who Should Buy a 6.6kW Solar System?
A 6.6kW solar panel system is well suited to:
- Average Australian households of 3–5 people.
- Homes with $250–$400 monthly electricity bills.
- Families working from home or running appliances during the day and looking to maximise savings.
- Smart homeowners looking to satisfy their power needs and get a return on your investment in the next 3-4 years.
Case Study: Family in Brisbane
A family of four in suburban Brisbane has an average quarterly electricity bill of around $1,050, or roughly $350 per month. Their daily usage is higher than average because they both work from home and run air-conditioning in summer.
They decide to install a 6.6kW mid-tier system using Canadian Solar panels and a Fronius inverter. The upfront cost after STCs is $6,700. In the first year, their system produces close to 9,500 kWh of electricity, with around 60% consumed directly in the home and the remainder exported to the grid.
Life after installation
The result is an annual saving of about $2,100 on their power bills. Compared with their original energy spend, this means they recover the full cost of the system in just under four years. Over a 25-year system lifespan, they’re on track for more than $35,000 in savings — even if feed-in tariffs continue to fall.
This example highlights how families with consistent daytime demand stand to get the fastest payback. In sunny states like Queensland, higher solar yields combined with good self-consumption ratios make the 6.6kW size a sweet spot.
Case Study: Couple in Melbourne
A retired couple living in Melbourne has smaller energy needs. Their bills average around $250 per month, and much of their power use happens in the evenings. They choose the same 6.6kW mid-tier solar package for $6,800.
Because Melbourne receives less sunshine than Brisbane, their system generates closer to 7,500–8,000 kWh annually. With only 40–45% consumed during the day, more of their energy is exported back to the grid at lower feed-in rates.
The results
Their total yearly savings come to around $1,600, translating into a payback period of roughly five years. While this is slower than in Queensland, it’s still an excellent return compared with almost any other household investment.
The couple also has the option to add a battery in future. This would allow them to store excess daytime energy and reduce evening grid reliance, improving both their savings and energy independence.
Installation & Quality Factors That Affect Cost
The final cost of a 6.6kW system can vary depending on the brands and equipment used, the complexity of the roof, the components needed suched as microinverters for partly shaded areas and other installation specifics.
Below we look at some factors that might affect the installation of a 6.6kW array.
Installation Complexity
- Steep or multi-storey roofs add $500–$1,500.
- Switchboard upgrades average $800–$1,200.
- Homes in regional areas may pay more due to travel time.
Cheap vs Good Quality Systems
It’s tempting to choose a “cheap 6.6kW solar system” advertised at $3,500–$4,500. These often use no-name panels with short warranties and unreliable inverters. If you speak to any solar installer who has been around for 10 years plus they will tell you the cheap systems last 10 – 15 years and they need replacing. Good quality systems cost more upfront but usually last 20–25 years with minimal issues.
Finding the Right Installer
GoSolarQuotes has an industry leading rating system for solar installers. We look at number of reviews, score of those reviews and years in business to give a trust rating. We find this system to be the best way to judge a solar installer.
- Always choose a SAA-accredited installer.
- Get at least three quotes to compare.
- Check reviews and warranty support.
Compare Solar Quotes from 3 installers in your area now.
What is the payback period for a 6.6kW solar system?
Most households see their system pay for itself in 4 to 6 years. In sunnier states like Queensland and WA, it’s closer to the low end, while in Victoria and Tasmania it can take a little longer. Factors that influence payback include your daytime power usage, feed-in tariff, and whether you choose budget or premium equipment. Even at the slower end, a payback period of 5–6 years is considered excellent given panels typically last 25 years or more.
Payback with Batteries
Without a battery, most 6.6kW systems pay back in 4–6 years. With a battery, ROI time typically extends to 7–10 years. However, households with high evening usage or electric vehicles can shorten that time frame, especially as feed-in tariffs decline.
