Short answer
A 6.6 kW rooftop system typically costs about $6,800 before the federal rebate and about $5,000 after it, and pays itself back in roughly 3.5 to 5 years depending on your state, power prices and how much of the solar power you use yourself. Larger systems export more power, so payback stretches as the system size grows.
A 6.6 kW rooftop solar system in NSW costs around $5,000-$6,000 after the federal STC rebate, saves a typical household roughly $1,200-$1,500 per year, and pays back in roughly 3.5-5 years, depending on how much of the power you use yourself. This page has an instant payback estimator that adjusts for your state, usage, current electricity rate, and feed-in tariff.
Solar payback estimator
Indicative figures, last checked in September 2026. Check energy.gov.au and solarquotes.com.au for current rebate values before signing a contract.
How solar payback actually works
Your solar panels save you money in two ways: self-consumption (electricity you generate and use yourself, avoiding the grid rate of 28-42c/kWh) and export (electricity you send to the grid, earning a feed-in tariff of 4-8c/kWh). The gap between those two numbers is huge, so payback is heavily driven by how much of your generation you use yourself.
A typical Australian household without a battery self-consumes about 25-40% of what their solar generates. If you're home during the day (retired, working from home, EV charging during daylight), you can push this higher. If you're at work 9-5 and the system is running to an empty house, you'll be closer to 20-25%.
2026 state-by-state figures
| State | Avg grid rate (c/kWh) | Typical feed-in tariff (c/kWh) | Daily gen per kW (kWh) |
|---|---|---|---|
| NSW | 32 | 5 | 4.0 |
| VIC | 28 | 5 | 3.7 |
| QLD | 30 | 6 | 4.4 |
| WA | 32 | 2.5 (9am-3pm), 10 (3-9pm) | 4.5 |
| SA | 42 | 4 | 4.4 |
| TAS | 29 | 8 | 3.5 |
| ACT | 28 | 8 | 4.0 |
| NT | 30 | 8 | 4.9 |
Feed-in tariffs have been falling in most states - what your retailer offers now may be lower than a year ago, and WA's tariff is much lower during the middle of the day. Compare retailers.
The federal STC rebate explained
Every rooftop solar install in Australia gets Small-scale Technology Certificates (STCs) that the installer claims and passes back to you as a discount. The rebate is roughly:
- 5 kW: ~$1,350 rebate
- 6.6 kW: ~$1,800 rebate
- 10 kW: ~$2,700 rebate
- 13 kW: ~$3,500 rebate
These are approximate figures for a zone 3 postcode at a certificate price of around $39; your installer's quote will show the exact number, which varies with your postcode and the certificate price. The scheme is phased out at the end of 2030, and the "deeming period" (which sets how many years of certificates you can claim upfront) drops by 1 year each year. That means installing in 2026 gets less than 2025, which got less than 2024. Waiting doesn't pay.
Typical prices by system size (2026 metro, quality installer)
| System size | Panels | Before STC | After STC |
|---|---|---|---|
| 5 kW | ~12 x 415W | $5,500 | $4,150 |
| 6.6 kW | ~16 x 415W | $6,800 | $5,020 |
| 8 kW | ~19 x 415W | $8,200 | $6,050 |
| 10 kW | ~24 x 415W | $10,500 | $7,810 |
| 13 kW | ~31 x 415W | $13,500 | $10,000 |
| 15 kW | ~36 x 415W | $15,500 | $11,460 |
Prices assume tier-1 panels + reputable inverter (Fronius, SMA, Sungrow) + CEC-accredited installer. Cheap installers can be 25-30% lower but come with real warranty and safety risk.
Solar Sharer and midday power offers
From 1 July 2026 the Solar Sharer rules require retailers in NSW, south-east Queensland and South Australia to offer a free or heavily discounted midday power window on default offers, and Victoria's Midday Power Saver follows from 1 October 2026. Where these apply, they change the value of midday self-consumption and of exports, and they favour loads you can shift to the middle of the day. This calculator does not model them, so check the offer your retailer will put you on.
Should I get a battery?
For most households without electric vehicles or high daytime use, battery payback is slower than solar alone - typically 8-12 years vs 4-5 years for solar. That said, the federal Cheaper Home Batteries Program, launched in July 2025, discounts the upfront cost through small-scale technology certificates (roughly $250-$270 per usable kWh for the first 14 kWh in September 2026), which improved the maths.
→ Use our battery payback calculator to see if adding a battery makes sense for your situation.
What affects your payback the most
- Self-consumption ratio: The single biggest lever. Every 10 percentage points of extra self-consumption typically shortens payback by 6-12 months.
- Roof orientation: North-facing is best. West-facing generates less at midday but more in the late afternoon - often better for households home in the evening. East-facing is worst for payback (peaks before you're home).
- Shading: Even partial shade on a few panels can slash total generation by 20-30% if the system uses string inverters. Microinverters or DC optimisers mitigate this at extra cost.
- Feed-in tariff trajectory: Every major state is cutting FiT in 2026-2028. Longer term, exported solar will approach zero value - which is what makes batteries and EV charging strategies attractive.
- Installer quality: A 5% cheaper installer with a 12-month warranty vs a mid-range installer with a 10-year workmanship warranty is almost never worth it. Solar warranty claims are common by year 5-7.
Frequently asked questions
How long do solar panels actually last?
Modern panels come with 25-year performance warranties, typically guaranteeing at least 80-85% output at year 25. Real-world data suggests good panels degrade about 0.5% per year, so year 20 you're still at ~90% output. Inverters last 10-15 years and usually need replacement once during the panel lifetime (add $1,500-3,000 to your 25-year total).
What size system should I get?
Rule of thumb: match daily generation to daily usage plus 30-50%. A household using 20 kWh/day in NSW (4 kWh/kW/day generation) matches at ~5-6.6 kW. Oversizing to 10 kW is worthwhile if you plan to add an EV or battery within 3 years, or if your roof has room and export tariff is decent.
Should I wait for cheaper panels / better rebates?
Panel prices have been flat since 2023 - the era of rapid price drops is over. STC rebates shrink every year until the scheme ends in 2030. Feed-in tariffs are dropping. Waiting almost always makes payback worse, not better.
How do I compare solar quotes?
The three things that matter: panel brand (tier 1 - LG, REC, Longi, Jinko, Trina), inverter brand (Fronius, SMA, Sungrow, Enphase), and installer warranty (10+ years workmanship, not just manufacturer warranty passed through). Whole-of-system price alone means nothing without those three.
→ Paste your solar quotes into our comparator to spot missing warranty terms, ambiguous inverter models, and unusually short payment terms.
Are cheap Chinese panels safe?
The tier-1 vs tier-3 divide isn't country of origin - almost all panels are Chinese-manufactured. Tier-1 means the manufacturer has been bank-financed for 5+ years (a proxy for "will still exist to honour warranty"). LG (tier-1) and no-name tier-3 both come from similar factory locations - the difference is corporate stability, not build quality per se.
What if I'm renting or planning to sell within a few years?
Payback of 4-5 years means selling before then loses money on the panels but you may recover partial value in the sale price - Australian data suggests solar adds around 3-4% to property value. If you plan to sell in year 6+, the maths usually still works.
Related tools
- Battery Payback Calculator - should you add a battery to your solar?
- Renovation Quote Comparator - paste your solar quotes for red-flag analysis
- Electrician Cost Australia - what to expect for the electrical side
- Renovation Budget Tracker - track spend against category budgets
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