Going solar: sizing a system and choosing an installer
How system size and component quality drive the price, why accreditation is non-negotiable, and the switchboard and battery costs to plan for.
Solar is one of the few home upgrades that pays you back, and prices have fallen far enough that a good system is within reach for most households. But the market is noisy, the headline prices hide a lot, and the cheapest quote is rarely the best value over the twenty-plus years the system should run.
Understanding what sets the price — and why accreditation matters — helps you compare quotes on what actually counts rather than on the number in the ad.
What a solar install involves
Solar is quoted as a complete installed system: panels on the roof, an inverter that converts their output to household power, the mounting and racking, and the electrical work to connect it to your switchboard and the grid. Advertised prices already have the federal STC rebate deducted, which is why they look lower than the sticker cost of the gear. The system size in kilowatts is the headline number, followed by the quality tier of the panels and inverter.
Your roof shapes the install. Single-storey tin roofs are the easiest; two-storey homes, tile roofs and layouts split across several faces take longer and cost more to fit. Batteries are the big optional add-on, storing daytime generation for evening use and blackout backup — whether one stacks up depends on your usage pattern and any state battery rebates.
How the cost works
Solar is priced as an installed system, with size the main driver: a 6.6 kW system is the common residential size and sits at the affordable end, a 10 kW premium system higher, and solar-plus-battery higher again. The calculator on this page shows indicative bands. Component quality is the quiet multiplier — budget, mid-range and premium panel and inverter tiers can swing a same-size quote by thousands.
Two costs catch people out. An old switchboard often needs upgrading before solar can be connected, which is a real extra. And a battery adds a substantial sum on top of the panels, partly offset by rebates in some states. Compare quotes on the specific panel and inverter models and their warranties, not just the headline price per kilowatt.
Accreditation and choosing an installer
This is the one hard rule: use an installer accredited by Solar Accreditation Australia. That accreditation is required both to claim the STC rebate and to connect legally to the grid, so it's not optional. The electrical work itself is licensed too — solar connection is a job for a licensed electrician. Ask for both the accreditation and the licence, and check them.
Beyond the credentials, judge on the gear and the warranties. The inverter is the component most likely to fail, so aim for a ten-year inverter warranty and check who honours it. Compare the actual panel and inverter models between quotes rather than the kilowatt price. A local installer who'll still be around to service a warranty claim is worth more than a fly-by-night offering the lowest number.
Mistakes to avoid
Solar regrets come from chasing the headline price — a cheap system on budget components with a distant installer — or from being surprised by a switchboard upgrade or a weak inverter warranty. Comparing the actual gear and credentials avoids all of it.
- Not confirming the installer is accredited by Solar Accreditation Australia
- Comparing on price per kilowatt instead of the specific panel and inverter models
- Overlooking a likely switchboard upgrade on older homes
- Skipping the inverter warranty check — inverters fail far more often than panels
- Assuming a battery pays off without checking your evening usage and state rebates
- Choosing a cheap, distant installer who won't be around to service a warranty claim
Indicative range only, not a quote — see the full guide for worked scenarios and what moves the price.
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