Typical payback on a 6.6 kW solar system
Typical payback on solar plus battery
STC discount applied at point of sale
Three things that drive the maths
Feed-in is worth far less than the power you buy
In Western Australia the credit you receive for exported solar is a fraction of the rate you pay to import, and it is lower in the middle of the day than in the late afternoon. That gap is the whole reason storage stacks up: every kWh you self-consume is worth several times an exported one.
Rebates change the starting line, not the running cost
The federal STC discount takes up to $7,300 off a solar and battery system at point of sale, and the WA Residential Battery Rebate adds $1,300 for eligible Synergy customers. Because both cut the upfront figure, they shorten payback without changing your annual savings.
Your usage pattern sets the ceiling
A home that is empty until 6pm exports almost everything it generates, so panels alone plateau quickly and a battery moves the needle. A work-from-home household with daytime air-conditioning gets more from extra panels first.
Compare the three options
Indicative ranges for WA households after rebates. We model your exact figures from a recent bill.
Solar only — 6.6 kW
- Upfront
- Lowest
- Annual saving
- $1,400–$1,900 / year
- Payback
- 3–5 years
- Best for
- First-time buyers, daytime users, tight budgets
Solar only — 10–13.2 kW
- Upfront
- Moderate
- Annual saving
- $2,000–$3,200 / year
- Payback
- 4–6 years
- Best for
- Ducted A/C, pools, larger roofs
Solar + battery
- Upfront
- Highest
- Annual saving
- $2,800–$4,200 / year
- Payback
- 6–9 years
- Best for
- Evening-heavy homes, blackout backup, EV owners
Payback FAQs
Should I install solar first and add a battery later?
It is a valid path, and a battery-ready hybrid inverter keeps it cheap to do. But installing together means one set of scaffolding, one grid application and one crew visit, and the STC discount applies to the whole job — so combined installs usually cost less than two separate ones.
What actually shortens payback the most?
Self-consumption. Shifting the dishwasher, pool pump and EV charging into solar hours costs nothing and can cut a year or more off payback before any hardware decision.
Does a battery still pay for itself if I have cheap night rates?
On a time-of-use tariff a battery can arbitrage — charge from solar or off-peak power and discharge through the expensive peak window. That improves returns rather than removing them, but the modelling has to use your specific tariff.
How long does the equipment last relative to payback?
Panels carry 25-year performance warranties and batteries are typically warranted for 10 years or a set cycle count. Even at the slower end of the payback range, the system keeps saving for well over a decade after it has paid for itself.
Get your payback modelled properly
We'll use your tariff, usage profile and roof to show payback for solar only and solar plus battery, side by side.