Payback
How long solar takes to pay for itself
Payback is one division: what it costs, over what it saves in a year. Everything difficult about it is in the second number, so here is that number worked out in the open.
Payback is one division. Take what the system costs, take what it saves you in a year, and divide the first by the second. Everything difficult about it is in the second number.
That is where the sales pitches live, because a saving figure can be made to say almost anything. So here is the arithmetic in the open, on the same assumptions our calculator uses: about 35 cents a kilowatt hour, and about 4 kilowatt hours a day from every kilowatt of panels, averaged over a Sydney year.
Neither is exact for your roof. They are close enough to tell you whether the number you have been quoted is in the right postcode.
Step 1 of 4
The only four things that decide it
Panel brand is not on this list, and neither is the inverter. They matter for how long the system lasts and how it is supported. They barely move the payback.
- What you pay for the systemThe installed price after the federal certificate discount, including anything the roof or the switchboard needs first. A quote that leaves those out is not the price.
- How much power you use, and whenThe single biggest lever, and the one nobody selling to you asks about. Power you use while the sun is up is worth the full retail rate. Power you export is worth a few cents.
- The size of the arrayBigger is not automatically faster to pay back. Past the point where you use the output, the extra rows only earn the export rate, and they lengthen the payback rather than shorten it.
- Whether you store itA battery costs more and saves more, and in Western Sydney the gap between the export rate and the evening rate is what decides whether it is worth it.
Step 2 of 4
The arithmetic, worked through
Take a 6.6kW system on a roof with nothing wrong with it. At 4 kWh a day per kW that is about 26 kWh a day, or roughly 9,600 kWh a year, averaged across summer and winter.
What that is worth depends entirely on how much of it you use rather than export. Every kilowatt hour you use yourself is 35 cents you do not pay. Every one you export earns whatever your retailer offers, which IPART benchmarks at 3.4 to 6.5 cents for 2026-27.
| How much you use yourself | Roughly worth a year | On a $4,500 system |
|---|---|---|
| 30%, out all day | About $1,200 | Around 4 years |
| 50%, someone home some days | About $1,700 | Around 3 years |
| 70%, someone home most days | About $2,300 | Around 2 years |
Notice what is doing the work in that table. It is not the system, it is the household. The same panels on the same roof pay back in two years or four depending on nothing but when the washing goes on.
Step 3 of 4
Where a battery changes the sum
A battery does not generate anything. What it does is move power from the middle of the day, when it is worth a few cents exported, to the evening, when you would otherwise be buying it.
In Parramatta that gap is unusually wide, and it is the strongest argument for storage anywhere in this business. Parramatta is on the Endeavour Energy network. IPART's benchmark for exports across the whole day in 2026-27 is 3.4 to 6.5 cents. Its evening benchmark on Endeavour, between 4pm and 8pm, is 16.9 to 19.9 cents.
- Benchmark for exporting across the day
- 3.4 to 6.5cBenchmark for exporting across the day
- Evening benchmark, Endeavour, 4pm to 8pm
- 16.9 to 19.9cEvening benchmark, Endeavour, 4pm to 8pm
- What you avoid paying by using it yourself
- 35cWhat you avoid paying by using it yourself
Retailers are not obliged to offer either rate, which is the catch. But the shape of it holds: a kilowatt hour held until the evening is worth several times one sent out at noon, and one you simply never buy is worth more again.
Step 4 of 4
Finance, and what to check before you sign one
We do not sell finance, arrange it, or take a commission on it. That is worth saying plainly, because a lot of solar payback maths quietly assumes a payment plan the seller earns from.
Payment plans, green loans and interest-free offers all exist for solar, through banks and through third-party lenders. If you are considering one, the questions are the same as for any credit.
- What is the total you repay, in dollars, not the weekly figure
- Whether an interest-free period converts to a rate at the end of it, and to what
- What the establishment and monthly account fees add over the term
- Whether paying it out early costs anything
- Whether the system price is the same as it would be paying cash, or loaded to cover the plan
If a system only makes sense once it is on a payment plan, the payment plan is the product and the solar is the packaging.
Figures checked against IPART’s 2026-27 solar feed-in tariff benchmarks and Endeavour Energy’s own network description on 31 August 2026. Everything worked through above is arithmetic from the stated assumptions rather than a promise about your house. Your quote shows the assumptions behind your own numbers, so you can check the sum instead of taking it on trust.
The two pages either side of this one: what each size costs and what you can claim in NSW.
Before you book
Payback questions we get asked
The ones that come up on nearly every first call, answered straight.
Not on the list? Call 1300 958 778 or send it through.
How long does solar take to pay for itself in Parramatta?
On our published starting prices and ordinary Sydney assumptions, a 6.6kW system lands somewhere between two and four years, and where it lands inside that range is decided almost entirely by how much of the output you use yourself rather than export. Someone home through the day pays it back faster than someone out from eight to six, on identical panels.
Does a bigger system pay back faster?
Only up to the point where you use what it makes. Past that, the extra panels earn the export rate, which IPART benchmarks at 3.4 to 6.5 cents against about 35 cents for power you use yourself. Beyond your own usage, a bigger array lengthens the payback rather than shortening it, unless you add storage.
How can I shorten the payback without spending more?
Move your biggest loads into daylight. The dishwasher, the washing machine and the pool pump are the usual three, and shifting them is worth more than adding panels. Going from using thirty per cent of your own output to fifty is roughly a year off the payback and it costs nothing.
Is a battery worth it in Western Sydney?
It depends on how much power you use after dark, and the case here is stronger than most. Parramatta is on the Endeavour Energy network, where IPART's evening feed-in benchmark for 2026-27 is 16.9 to 19.9 cents between 4pm and 8pm, against 3.4 to 6.5 cents across the day. Holding power for the evening rather than exporting it at noon is where the value sits.
Do you offer finance or a payment plan?
No. We do not sell finance, arrange it or take a commission on it. Payment plans and green loans exist through banks and third-party lenders and you are free to use one, but the price we quote is the price, and it is the same whether you pay it in one go or borrow it elsewhere.
Are your payback numbers a guarantee?
No, and treat anyone who offers one carefully. Every figure on this page is arithmetic from stated assumptions about tariffs, yield and usage, all of which move. What we will do is show you the assumptions behind your own numbers in writing, so you can check the sum rather than take it on trust.
Get the payback figure for your own roof.
Send the address and roughly what your quarterly bill runs to. You get a system size, a price and a payback figure in writing, before you commit to anything.