For a household using 25 kWh a day, about $857 a quarter at WA's 33.3c a unit, the calculator puts 10–13kW solar at $7,670 to $12,670 after rebates, and 10–13kW solar + ~15kWh battery at $9,740 to $20,740.
I am an advisor, not an installer and not a lead broker. You pay nothing at any point.
See what my home should costA young family in a new house, out on weekdays, using 25 kWh a day.
A ballpark for one example household, not a quote. The low end of each range is what a competitive installer charges; the high end is a poor quote for the same equipment. Prices are from the same calculator the free assessment uses, with WA rates and rebates, and sun hours are its figure for Western Australia.
Four real households, run through the same calculator this site uses for an individual report. Panels only, no battery, clean roof, someone home some of the time. Prices are after every rebate that applies in Western Australia.
| Household uses | Their quarterly bill | System | After rebates | Saves a year | Pays for itself |
|---|---|---|---|---|---|
| 10 kWh | $403 | 6.6kW solar | $6,050 to $8,050 | $480–$720 | 10+ years |
| 15 kWh | $554 | 6.6kW solar | $6,050 to $8,050 | $640–$950 | 8–10 years |
| 22 kWh | $766 | 10–13kW solar | $7,800 to $12,800 | $980–$1,470 | 7–10 years |
| 30 kWh | $1,008 | 13–15kW solar | $9,550 to $15,600 | $1,290–$1,940 | 6–9 years |
The bill column is what that household actually pays in Western Australia at 33.3c a unit, which is why the same house has a different bill in every state. Savings depend on how much of the generation gets used on site rather than exported, and at 2c a unit for exports that is the number that decides the answer. A household out all day saves less than the figures above; one home most days saves more. Every figure is produced by the calculator, not written down, so it moves when the published rates move.
Brabham is a new suburb: brand-new houses in the Swan Valley corridor, the youngest population on this list, and more than eight in ten homes on a mortgage. Any system here is going on a new house under the 2026 rules, so the setup is decided from day one.
In Perth, the poles and wires belong to Western Power and the bill, for most homes, comes from Synergy. Brabham is on that network, the South West Interconnected System[1], and its rules are the ones a quote here has to be designed to.
The 1 May 2026 rules. A system installed or upgraded on or after 1 May 2026 has to be able to be remotely disconnected and reconnected in an emergency, and Synergy talks to it using CSIP-AUS. Keep it connected and it can join flexible export or virtual power plant products as they arrive; if you would rather not, or your internet is unreliable, it is set to a fixed 1.5kW export limit. Your own use of your solar is unaffected either way, and systems installed before 1 May 2026 are not affected[1]. Western Power's technical requirements put the static base limit at 1.5kW and allow up to 5kW where the system is managed under an agreement with your retailer[2].
What that means in practice: a quote written now should name an inverter that meets Synergy's requirements and say which way the system will be set up. Exports earn little for most of the day, so size the array to what the house uses, not to the size of the roof.
At the 2021 Census the median Brabham resident was 29. 97.4% of occupied homes were separate houses and 82.7% were owned with a mortgage, more than double the Western Australia figure of 40%. Only 4.1% were owned outright.[3]
New houses, young households, big mortgages.
Things worth knowing before an installer walks the roof:
All of that describes the area, not your house. Two homes on the same street can be completely different jobs. Put your address in and the assessment works off the actual property rather than a town average.
A system installed or upgraded on a Brabham house now falls under the 1 May 2026 rules: able to be remotely disconnected and reconnected in an emergency, with Synergy communicating over CSIP-AUS, or set to a fixed 1.5kW export limit[1]. If your builder fitted a system, check whether adding to it counts as an upgrade, and whether its inverter can meet the requirements.
For a battery, the WA rebate needs the battery on Synergy's supported list and in a virtual power plant[4]. Get both confirmed on the quote.
These are examples, not an average for Brabham. They are picked to show how the answer moves for the kinds of household the census shows are common here. Clean roof, no shading, WA rates and rebates, and the battery prices assume it is installed before the federal battery discount steps down on 1 January 2027.
| Option | System | After rebates | Saves a year | Pays for itself |
|---|---|---|---|---|
| Change plan and cut waste first | No system | $0 | $170–$510 | Nothing to pay back |
| Solar panels only | 10–13kW solar | $7,670 to $12,670 | $870–$1,300 | 7–10+ years |
| Solar plus a 10kWh battery | 10–13kW solar + 10kWh battery | $7,500 to $18,100 | $1,600–$2,370 | 4–9 years |
| Solar plus a 15kWh batteryPays back fastest | 10–13kW solar + ~15kWh battery | $9,740 to $20,740 | $1,960–$2,760 | 4–9 years |
Solar plus a 15kWh battery. It pays back fastest of the options open to you, which is the only measure here that accounts for what the thing actually costs.
Before any of it: get onto a competitive retail offer. It costs nothing, it takes an afternoon, and on a bill your size it is worth roughly $170 to $510 a year. Every payback below gets shorter once you are paying less per kWh, so it is worth doing first either way.
| Option | System | After rebates | Saves a year | Pays for itself |
|---|---|---|---|---|
| Change plan and cut waste first | No system | $0 | $130–$390 | Nothing to pay back |
| Solar panels only | 10–13kW solar | $7,670 to $12,670 | $850–$1,280 | 7–10+ years |
| Solar plus a 10kWh batteryPays back fastest | 10–13kW solar + 10kWh battery | $7,500 to $18,100 | $1,580–$2,180 | 4–9 years |
Solar plus a 10kWh battery. It pays back fastest of the options open to you, which is the only measure here that accounts for what the thing actually costs.
Before any of it: get onto a competitive retail offer. It costs nothing, it takes an afternoon, and on a bill your size it is worth roughly $130 to $390 a year. Every payback below gets shorter once you are paying less per kWh, so it is worth doing first either way.
"Pays for itself" is the range between a competitive quote and a poor one for the same equipment, and 10+ means not inside ten years. The battery ranges are wide for the same reason. Your own usage, roof and timing will move every figure here, which is what the free assessment works from.
Applied by the installer as a discount on the quote, not something you claim. It scales with system size: on the 10–13kW solar in the first example above the calculator counts $2,330. It falls a little each year until the scheme ends in 2030.
There is no state rebate on solar panels in WA, but there is one on batteries: up to $1,300 for Synergy customers and up to $3,800 for Horizon Power customers, still open in May 2026[5]. To get it, the battery has to join a virtual power plant and be on Synergy's supported list, and low- and middle-income households can borrow up to $10,000 interest-free for solar and batteries[4]. The calculator includes the $1,300 Synergy rebate in every battery price on this page.
The federal Cheaper Home Batteries Program applies on top. On a 10kWh battery the calculator counts $2,520. The rate is set by the date the battery is installed, not when you order it, and it steps down on 1 January 2027 and every six months after that[6]. Larger batteries earn less per extra kWh: the full rate applies to the first 14kWh.
WA's Distributed Energy Buyback Scheme pays Synergy customers 10c a unit for exports between 3pm and 9pm and 2c at other times, on up to 50 units a day[7]. The calculator assumes 2c a unit, the rate for most of the day, which is why every example on this page is decided by how much power the house uses itself. For the price you pay, it uses Synergy's regulated Home Plan (A1) rate of 33.3c a unit from 1 July 2026[8]; your actual rate depends on your retailer and plan, and time-of-use plans and Horizon Power customers will differ.
The full breakdown, with dates, is in WA solar rebates explained.
Already holding a quote? This is how I read one, line by line.
For the first example household on this page, 25 kWh a day, the calculator puts 10–13kW solar at $7,670 to $12,670 after WA rebates, and 10–13kW solar + ~15kWh battery at $9,740 to $20,740. The range is the gap between a competitive installer and a poor quote for the same equipment. Your own figure depends on your usage and roof, which is what the free assessment works out.
Western Power. Perth is on Western Power's network, the South West Interconnected System, and most homes buy from Synergy. Systems installed or upgraded from 1 May 2026 must be remotely manageable in an emergency; stay connected and you can join flexible export or VPP products, or take a fixed 1.5kW export limit. Western Power's maximum is 5kW where the system is managed under a retailer agreement.
Check the inverter first. Adding panels, another inverter or a battery counts as an upgrade under WA's 1 May 2026 rules, so the system must be remotely manageable in an emergency or take a fixed 1.5kW export limit. For the WA battery rebate, the battery must be on Synergy's supported list and join a virtual power plant.
The installer, and only when a job completes. Never the homeowner. No installer can buy placement, and nothing about you reaches one until you ask me to make the introduction.
About a minute. You get the system size, what it should cost, and what it saves. No one calls you unless you ask.
Start My Free CheckIndependent explainers on the parts of this that actually change the answer.
Prices, savings and paybacks come from this site's calculator, using WA rates verified 2026-10. Everything else is from the sources below, read on the date shown. Rules and rebates change, so check the source before you rely on one.