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6.6kW Solar System Australia 2026
Everything you need to know about 6.6kW solar system cost, performance, and savings in Australia 2026. The most common residential system size explained.
Panels
15–18
Daily Output
22–30 kWh
Cost After STCs
$3,800–$6,500
Annual Savings
$1,400–$2,200
Payback Period
3–4.5 years
Roof Space
30–40 m²
Ideal for: Average households (2–4 people), moderate electricity usage, most Australian homes.
Why 6.6kW Is Australia's Most Popular System
The 6.6kW system dominates Australian residential solar — and for good reason. It's the maximum panel capacity that can be paired with a standard 5kW single-phase inverter (a legal 133% "oversizing" ratio). This means you get 32% more panels without needing a larger, more expensive inverter. The result is exceptional value: more energy, minimal cost premium. Installers buy 6.6kW systems in massive volume, pushing prices to their most competitive.
How Much Power Does a 6.6kW System Produce?
Daily output ranges from 22 kWh (Melbourne winter) to 35+ kWh (Brisbane summer). On an annual basis, expect 8,000–11,000 kWh depending on your location. For context, the average Australian household uses about 16–20 kWh per day. A 6.6kW system comfortably covers daytime usage and exports the surplus to the grid for feed-in credits.
Cost Breakdown by State
The national average for a quality 6.6kW system is $5,500–$8,500 before STCs, dropping to $3,800–$6,500 after. Victoria is often cheapest due to the additional $1,400 Solar Homes rebate. Queensland and WA benefit from Zone 1 STC values (highest nationally). The premium you pay for top-tier panels (REC Alpha, SunPower Maxeon) over mainstream brands (Jinko, Trina) is typically $1,000–$2,000 — whether that's worth it depends on your roof space and budget.
Adding a Battery to a 6.6kW System
A 6.6kW system pairs well with a 10kWh battery ($7,000–$10,000). This combination can push self-consumption from ~35% to ~70%, dramatically reducing grid purchases. With the new federal Cheaper Home Batteries Program (launched 2025), battery costs are dropping further through additional STC incentives. For homes with time-of-use tariffs, battery payback periods are now approaching 7–8 years in high-tariff states like SA.
6.6kW vs 10kW — When to Go Bigger
If your quarterly bill exceeds $550, your household is growing, or you're planning to add an EV, consider stepping up to 10kW. The price jump is $1,500–$3,000 more, but you'll need a larger inverter (potentially 3-phase) and more roof space. For most households with $350–$550 quarterly bills, 6.6kW is the sweet spot.
6.6kW System — Cost & Output by State
| State | Daily Output | Cost After STCs | Annual Savings |
|---|---|---|---|
| QLD | 29 kWh/day | $4,000–$6,000 | $1,600–$2,200 |
| NSW | 26 kWh/day | $4,200–$6,500 | $1,500–$2,000 |
| VIC | 22 kWh/day | $3,200–$5,200 | $1,200–$1,700 |
| SA | 28 kWh/day | $4,000–$6,000 | $1,800–$2,400 |
| WA | 30 kWh/day | $3,800–$5,800 | $1,500–$2,000 |
| TAS | 20 kWh/day | $4,500–$6,800 | $1,000–$1,400 |
ADVANTAGES
✓Best value system size — sweet spot of cost vs output
✓Pairs perfectly with a 5kW inverter (standard configuration)
✓Covers most household electricity needs during the day
✓Strong export income from surplus generation
✓Good future-proofing for battery addition later
✓Most competitive pricing due to installer volume
CONSIDERATIONS
•May not fully cover very high usage households (>$600/quarter bills)
•Still requires grid power for evening use without a battery
•Roof needs at least 30m² of unshaded, suitable area
Find out if a 6.6kW system is right for your home — takes 60 seconds.
Get My Solar Score ☀Frequently Asked Questions
How much does a 6.6kW solar system cost in Australia?
A 6.6kW solar system costs approximately $3,800–$6,500 after federal STC rebates in 2026. Exact pricing depends on your state, panel brand, inverter choice, and installer. Premium tier-1 panels may add $1,000–$2,000 to the base price.
How much electricity does a 6.6kW system produce?
A 6.6kW system produces approximately 22–30 kWh on average. Output varies by location — Perth and Darwin get more sun than Melbourne or Hobart — and by roof orientation. North-facing roofs in Australia produce the most energy.
How much will I save with a 6.6kW solar system?
Typical savings with a 6.6kW system are around $1,400–$2,200 per year, depending on your electricity rate, usage patterns, and how much solar energy you self-consume versus export to the grid. Adding a battery increases self-consumption from ~35% to ~70%.
How many panels are in a 6.6kW system?
A 6.6kW system typically uses 15–18. Most modern panels are 400–440W each. You'll need approximately 16 panels at 420W to reach 6.6kW. Your installer will confirm exact panel count based on the brand selected.
Is a 6.6kW system big enough for my home?
That depends on your electricity usage. Check the "Ideal For" section above for detailed household profiles. As a rule of thumb: divide your quarterly bill by $150 to estimate the kW you need. Our free solar score tool gives you a personalised system size recommendation.