Price guide · 6.6kW solar and battery
6.6kW solar and battery in Perth: cost and savings
The 6.6kW system is Perth's standard rooftop size. What it costs with a battery, before and after rebates, which battery suits it, and around what it saves.
6.6kW solar with a 10 kWh battery: around $10,000–$18,500 after rebates
The model tops out around $2,030 a year for a typical home. Winter and cloudy days still buy from the grid, so most homes save less. Only a quote for your roof and switchboard is a real price.
What a 6.6kW system costs, with and without a battery
Indicative, not a quoteInstalled prices from budget to premium equipment, before and after every rebate that applies today.
| System | Before rebates | Rebates | You pay |
|---|---|---|---|
| 6.6kW solar onlySolar STCs only | $6,300–$9,800 | $1,800 | $4,500–$8,000 |
| 6.6kW + 5 kWh battery | $12,800–$18,800 | $3,800 | $9,000–$15,000 |
| 6.6kW + 10 kWh battery | $15,800–$24,300 | $5,800 | $10,000–$18,500 |
| 6.6kW + 13.5 kWh battery | $17,900–$28,100 | $6,700 | $11,200–$21,400 |
How to read this
The rebates in those prices
WA policy source · verified 31 Jan 2026Three schemes take money off. The table above already applies all three.
- Solar STCs
- About $1,800 on 6.6kW of panels, already off the advertised price. The value falls each 1 January as the scheme winds down.
- Battery STCs
- 6.8 certificates per usable kWh for installs in May-Dec 2026, stepping down to 5.7 in Jan-Jun 2027.
- WA Battery Scheme
- $130 per kWh on the first 10 kWh, up to $1,300. Synergy customers who join a VPP, which is a condition of the rebate.
Who qualifies and how to claim: the WA battery rebate guide.
Which battery suits 6.6kW of solar
Size the battery to your evening and overnight use. Your panels cover daytime use directly.
Rule of thumb
For a typical Perth home using about 18 kWh a day, around 10 kWh. The WA rebate covers the first 10 kWh; a bigger battery can still make sense with high evening use, an EV or backup needs, but the extra capacity carries no WA rebate.
Work out your own size with find my battery.
What it could save, at most
Each figure is a modelled ceiling: panels covering the daytime load, the battery the evening load, capped at what the home pays for power. Real savings sit below it.
| Household | Usage charges a year | Modelled ceiling | Payback at the ceiling |
|---|---|---|---|
| A typical Perth homeAbout 18 kWh a day, 10 kWh battery | $2,180 | $2,030solar $1,220, battery $810 | 5–9 years |
| A home that uses what the 6.6kW array makesAbout 28 kWh a day, 10 kWh battery | $3,400 | $2,260solar $1,320, battery $940 | 4–8 years |
Assumptions
What moves the price
Why two quotes for the same size can sit thousands of dollars apart.
- Size
- Battery price scales with usable kWh. The WA rebate stops growing past its cap, and the federal STCs taper on bigger batteries.
- Brand tier
- The spread in every band above is budget to premium equipment, with longer warranties at the top.
- Inverter type
- A hybrid inverter runs the panels and the battery together, and is the usual choice for a new system.
- Adding to existing solar
- An AC-coupled battery can sit beside your current inverter, but in WA adding a battery to an existing system counts as an alteration and can trigger whole-of-site compliance: the whole installation may need to meet today's rules. For many existing systems the sound path is replacing toward a DC-coupled / hybrid-inverter setup rather than expanding an AC-coupled one, avoiding future compliance limitations.
- The site
- Switchboard upgrades, single or three-phase power, cable runs and backup wiring all add cost.
6.6kW solar and battery questions
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