A typical Australian home solar system costs a few thousand dollars after the federal discount, and most of the spread in quotes comes from the equipment, the roof and the installer, not from the discount itself. A 6.6 kW system, which is the common household size, has recently been quoted at somewhere between about $4,500 and $7,500 once the STC discount is taken off. Quotes at the bottom of that range tend to have compromises, and those at the top are not always better.
This guide explains where the number comes from, so you can read a quote line by line. Prices change, and sources disagree by a few hundred dollars, so use the ranges here as a sanity check and get several current quotes. Prices for a later part of the year are covered in solar panel prices in Australia for 2026.
Cost by system size
Installers price roughly per watt, with economies of scale as systems get larger. After the STC discount, and including GST, the range most homeowners see looks like this. These are indicative bands, not quotes.
| System size | Typical panels | Indicative price after STC discount |
|---|---|---|
| 3 kW | 7 to 8 | $3,000 to $4,500 |
| 6.6 kW | 15 to 18 | $4,500 to $7,500 |
| 10 kW | 22 to 25 | $6,500 to $10,000 |
Notice the shape: doubling the size does not double the price, because the fixed costs of the job (labour to arrive, switchboard work, inverter, paperwork) are spread across more panels. That is why a bigger system often has a better per-watt price, even though the total is higher.
The STC discount, in numbers
Most of the federal support is a discount delivered through Small-scale Technology Certificates. When your installer completes the job, certificates are created for the electricity the system is expected to generate over the deeming period. For 2026 installs, that period is five years. It drops to four in 2027, and to one in 2030, with the scheme ending on 31 December 2030.
The number of certificates is system size in kW, times the zone rating for your postcode, times the deeming years. Zone ratings are 1.622, 1.536, 1.382 and 1.185.
- 6.6 kW, zone 1.622 (the sunniest zone), 5 years: 6.6 x 1.622 x 5 = 53.5, so 53 STCs
- 6.6 kW, zone 1.382, 5 years: about 45 STCs
- 6.6 kW, zone 1.185, 5 years: about 39 STCs
At a market price of roughly $38 to $40 per certificate, that is about $1,500 to $2,100, depending on your zone. Your installer usually takes it off the price up front. If you want to run the numbers for your postcode, use our guide to deeming periods and zone ratings and the answer on how much the rebate is on a 6.6 kW system.
What pushes a quote up or down
Panels. Tier-one panels from established manufacturers cost more than lesser-known brands. The cheapest quote often means unknown panels, a shorter warranty, or both.
Inverter. The inverter is the part most likely to fail in the first 15 years. Brand, warranty length and whether it is battery-ready all move the price.
Roof. A simple pitched tile roof is cheaper to install than a steep or multi-storey one. Switchboard upgrades add cost where the old one cannot take the new circuit.
Installer. A well-run business with accredited staff, proper insurance and workmanship cover charges more than a one-person operation that cuts corners. You are paying for the person who will be there if something goes wrong.
Extras. Optimisers, monitoring, three-phase upgrades and a battery-ready inverter all add dollars.
Reading a quote
A good quote has these lines and no mystery:
- System size in kW, number of panels, and the brand and model of each
- Inverter brand, model and size
- Total price before the STC discount
- The STC discount shown as a separate line, with the number of certificates and the rate used
- Net price you pay
- Warranty terms for panels, inverter and workmanship
- The installer’s accreditation number
If the STC line is missing, or is a round number with no certificate count, ask. Our guide to reading the STC discount on a solar quote shows what to look for.
What is not included
Some costs are not in the headline number. Ask about:
- Switchboard upgrades, if needed
- Metering or network application fees for your distributor
- Roof or access charges for steep or tiled roofs
- Removal of an old system, if replacing
Also ask whether state incentives apply. Solar Victoria’s rebate, for example, has a household income cap, which fell to $150,000 on 1 July 2026. Check the program’s official page for the amount available.
From the desk: Be wary of a quote that gives the net price only and is not willing to show you the STC line. The certificate rate is a market price that changes, and your installer is entitled to a margin on it, but you are entitled to see it. A transparent installer will tell you the number of certificates and the rate used, and what happens to the price if the rate moves before installation.
Does it pay back?
Cost matters because it feeds payback. A 6.6 kW system at $5,500 that saves, say, $1,200 to $1,600 a year on electricity (depending on usage, tariffs and how much you use during the day) pays back in roughly 3.5 to 4.5 years. A system at $7,500 saving the same takes longer. We take that arithmetic further in is solar worth it in 2026.
Should you wait?
The discount falls every January, so waiting for prices to fall usually works against you on the STC side, even if panel prices drift down. The answer on whether to install solar now or wait covers the trade-off.
Sizing before you price
The cheapest system is not the best-value one if it is the wrong size. Look at your electricity bill for daily usage in kWh, and note when you are home. A household that uses most of its power in the evening gains less from a very large array than one with someone home all day, unless a battery is planned. Many installers quote 6.6 kW as a default because it fits most roofs and the inverter limits are well understood, but a 5 kW system can be the better fit for a small household. Ask your installer to explain the size they recommend using your own usage, and what the export limit from your network will be, because some distributors cap how much you can send to the grid.
What to do next
- Get three itemised quotes for the same size and compare line by line
- Check the installer’s accreditation and licence before you sign
- Ask what rate the STC discount was calculated at and whether it is locked
- Browse our resources and the STC trading overview if you want to see how installers turn certificates into cash, which is the reason the discount exists at all