The honest answer: in 2026 a quality rooftop solar system in Australia costs roughly $5,000 to $7,500 for a common 6.6 kW size, and roughly $8,000 to $12,000 for a 10 kW system, fully installed and after the federal STC rebate. That works out to about $0.90 to $1.20 per watt installed. Regional areas like Mackay can sit slightly above the big-city average. Below is the breakdown by size and the things that move the price.
The short version
Most homes land on a 6.6 kW to 13 kW system. After the federal rebate that is usually a $5,000 to $14,000 job depending on size, panel and inverter choice, and how complex your roof and switchboard are. Cash price per watt drops as the system gets bigger, so a 10 kW system is rarely double the price of a 5 kW one.
What solar panels cost by system size
These are installed prices for a quality system from an accredited installer, after the federal STC discount is applied.
| System size | After federal rebate (installed) | Suits |
|---|---|---|
| 6.6 kW | $5,000 to $7,500 | Smaller homes, modest daytime use |
| 10 kW | $8,000 to $12,000 | Family homes, ducted air-con |
| 13.2 kW | $10,000 to $14,000 | Large homes, pool, EV, or a future battery |
A 6.6 kW system is the long-standing default because it pairs well with a standard single-phase connection. In Mackay, where air-conditioning runs hard, many households now go straight to 10 kW or more so there is enough daytime generation to cover cooling and to charge a battery later.
The federal rebate is already in those numbers
The prices above are after the federal STC discount for rooftop solar. That discount knocks several thousand dollars off the sticker price, it is applied upfront by your installer, and it steps down over time. So a 6.6 kW system that is “$5,500 installed” is the after-rebate figure, not a separate cheque you chase later. This is a different scheme to the battery rebate, which we cover in the solar battery rebate QLD guide.
What moves the price up or down
- Panel tier. Premium panels (the brands with the strongest warranties and performance) cost more than budget panels but hold output longer. We cover which is worth it in best solar panels in Australia.
- Inverter type. A single string inverter is the standard. Microinverters or optimisers add cost but help on roofs with shading or several orientations.
- Roof and access. Tin is quicker than tile. Two-storey, steep, or split roofs add labour.
- Switchboard upgrade. Older boards sometimes need an upgrade to pass inspection, which adds a few hundred dollars.
- Single vs three phase. Three-phase homes can take larger systems but the inverter costs more.
Be careful with prices that look too cheap
You will see “6.6 kW from $2,990” style ads. Those usually pair the cheapest panels and inverter on the market with thin workmanship cover, and the real-world result is underperformance and warranty headaches. For an honest budget in 2026, use the ranges in the table above and ask any installer to put the panel brand, inverter brand and workmanship warranty in writing.
What about ongoing costs?
Rooftop solar has almost no running cost. The main one in the tropics is cleaning, because Mackay’s pollen, salt and cane dust build up faster than in a dry city. We explain that in why Mackay panels need cleaning more often. Inverters are the part most likely to need replacing, usually after 10 to 15 years.
Frequently asked questions
How much does a 6.6 kW solar system cost in 2026?
Roughly $5,000 to $7,500 fully installed after the federal STC rebate, depending on panel and inverter brand and how complex your roof is. The price per watt falls as the system gets bigger.
How much does a 10 kW solar system cost?
Roughly $8,000 to $12,000 installed after the rebate. In Mackay a 10 kW system is a common choice because it covers heavy air-conditioning use and leaves room to add a battery later.
Is the rebate already included in those prices?
Yes. The figures above are after the federal STC discount, which your installer applies upfront. There is no separate rebate cheque.
Does a bigger system cost proportionally more?
No. A lot of the cost is fixed labour and electrical work, so a 10 kW system is rarely double a 5 kW one. The cost per watt usually drops as the system gets larger.
Will the price keep dropping if I wait?
Hardware prices are fairly flat now and the rebate steps down over time, so waiting tends to cost you the rebate rather than save you on hardware.
Sources
- Solar system price ranges, Solar Choice Price Index
- Small-scale solar STC rebate, energy.gov.au
- Buying guidance, CHOICE solar panels guide
What to do next
Once you know the budget, the next question is sizing. Our plain-English guide covers what size solar system and battery you need, and if you want to compare hardware, see best solar panels in Australia.
Next Phase Solar quotes residential solar across Mackay at a fixed price, not a range, with the panel and inverter brand named on the quote.
Get a fixed-price solar quote at /quote
Last reviewed June 2026.
