Check your rebate eligibility
TL;DR: A 5kW solar system costs $3,600 to $6,000 after the STC rebate in 2026. It suits smaller homes and low-usage households. But for most homes, a 6.6kW system on the same inverter is only $500 to $900 more and produces 15 to 20% more electricity. Unless you have limited roof space or very low usage, 6.6kW is almost always better value.
A 5kW solar system typically consists of 10 to 12 panels at around 440 to 460 watts each, connected to a 5kW inverter. It uses around 22 to 25 square metres of roof space, which is roughly the footprint of a single parking space per pair of panels.
On a good day in Sydney or Brisbane, a 5kW system generates around 18 to 22 kilowatt-hours. In Melbourne or Hobart, expect 15 to 18 kWh. That production covers the daily usage of a one-to-two person household or a small home with modest appliance use.
Here is the thing most installers will tell you: for most homes, the real choice is not 5kW versus 6.6kW inverter capacity. The inverter price is similar. The question is how many panels to put on it. A 5kW panel array costs $500 to $900 less than a 6.6kW array on the same inverter, but the 6.6kW array generates meaningfully more across the day. For most buyers, the extra investment pays back in under a year through additional savings.
5kW solar system price by state
All prices below are after the federal STC rebate has been applied. The STC rebate on a 5kW system is worth approximately $2,200 to $2,800 depending on your state and the current STC trading price.
| State | Price range (after rebate) | Daily output | Typical payback |
|---|---|---|---|
| NSW | $4,000\u2013$5,800 | ~20 kWh | 3.5\u20135.5 yr |
| VIC | $3,800\u2013$5,600 | ~17 kWh | 4\u20135.5 yr |
| QLD | $3,600\u2013$5,400 | ~22 kWh | 3\u20134.5 yr |
| SA | $4,100\u2013$6,000 | ~21 kWh | 2.5\u20134 yr |
| WA | $3,900\u2013$5,600 | ~28 kWh | 3.5\u20135 yr |
| TAS | $4,300\u2013$6,100 | ~16 kWh | 4.5\u20136 yr |
| NT | $4,600\u2013$6,500 | ~24 kWh | 4\u20135 yr |
| ACT | $4,000\u2013$5,700 | ~19 kWh | 4\u20135 yr |
South Australia has the shortest payback despite mid-range system costs because electricity prices are the highest in the country, at around 42 to 46 cents per kilowatt-hour. Every unit of solar you use directly saves more in SA than anywhere else on the mainland. For state-specific rebates on top of the federal STC, check our rebates overview.
Check Your Rebate Eligibility
Enter your postcode to check rebate eligibility in your area.
Over 3.6 million homes already claiming rebates
5kW vs 6.6kW: when does the extra outlay make sense?
Both a 5kW and a 6.6kW system use a 5kW inverter. The difference is the number of panels. Under the Clean Energy Council's 133% oversizing rule, you can connect up to 6.6kW of panels to a 5kW inverter to capture more generation during shoulder hours. The cost difference between configurations is the cost of four to six extra panels: typically $500 to $900.
| 5kW panels | 6.6kW panels | |
|---|---|---|
| Number of panels | 10\u201312 | 14\u201316 |
| Roof space needed | ~22m² | ~30m² |
| Daily output (Sydney) | ~20 kWh | ~26 kWh |
| Price premium | Base | +$500\u2013$900 more |
| Extra annual saving | Base | +$200\u2013$400/year |
| Payback on extra cost | n/a | ~1.5\u20133 years |
The extra panels pay for themselves quickly. Unless you have a tight roof with under 24 square metres of usable space, or you are genuinely a very low-usage household, the 6.6kW configuration is the better investment. See our full 6.6kW system price guide for detailed pricing on that option.
When a 5kW system is the right choice
Tight roof space
If you have less than 24 square metres of clear, north-facing (or north-east/north-west) roof space after accounting for ridges, skylights, and roof penetrations, a 5kW system may be the practical maximum you can fit.
Low electricity usage
If your household genuinely uses less than 12 to 15 kWh per day, a 5kW system will cover most of your consumption. A larger system would generate more than you can use or export, with diminishing returns.
Budget constraint
If the difference between a 5kW and 6.6kW system takes you over a budget threshold, a 5kW system is still a sound investment. You can always add panels later if export limits or roof space allow.
Proving the concept before expanding
Some homeowners prefer to start smaller and add a battery once they understand their usage pattern. A 5kW system with a battery can be a sensible starting point before expanding the panel count.
See How Much You'd Save
Enter your postcode to see your estimated rebate amount.
Over 3.6 million homes already claiming rebates
What should be included in a 5kW quote
- check_circle10–12 solar panels (440–460W each) – specific brand and model named in the quote
- check_circle5kW inverter – brand and model specified (e.g. Fronius Primo 5.0, Sungrow SG5.0RS)
- check_circleRoof mounting system – rails, clamps, and brackets suited to your roof type
- check_circleAll electrical wiring – DC and AC cabling, conduit, isolators
- check_circleInstallation labour – typically a half to full day for a simple 5kW install
- check_circleGrid connection paperwork – application to your distributor (DNSP)
- check_circleSTC rebate applied as discount – shown as a line item on the quote, not buried in the total
Switchboard upgrades ($500 to $1,500) and meter reconfiguration ($0 to $300) are sometimes excluded from the headline price. Ask before signing. A good installer will flag these after the site inspection rather than springing them on you after the work begins. Our guide to reading solar quotes walks through exactly what to look for.
The next step
If you have any questions about the information in this guide, feel free to get in touch:
Email: hello@whysolar.com.au
Tel: +61 433 405 530
If you're considering solar panels or batteries for your home, Bec and the team can help you get quotes from trusted, pre-vetted local installers:
Written by
Bec RamirezAussie Mum & Energy Expert
Helping families navigate the switch to solar with practical, real-world advice. Bec focuses on the financial side — rebates, bill savings, and financing options — so everyday Australians can see real value from going solar.
Learn more about Bec Ramirez