A solar quote depends on system size, roof type and layout, shading, panel and inverter brand, whether a battery is included, switchboard or electrical upgrades, site access, and the STC and battery rebates taken off. Two quotes for the same kW can differ because they include different equipment and scope. Compare brands, inclusions and warranties line by line.
- System size, roof, shading, equipment and electrical work drive the quote.
- Watch for missing brand names, phone prices, pressure to sign and vague rebate lines.
- Rebates should be shown as separate lines, not one vague discount.
- Compare brand names, usable battery kWh, inclusions and warranties line by line.
- Cheaper quotes often mean different gear or missing scope.
1. System design: size, roof and shading
System size is the biggest single factor. It should come from your usage, not your roof size. Most Adelaide family homes land between 6.6 and 10 kW, with more for a battery, EV or big household. See how many solar panels you need.
Roof layout changes the labour. A single north-facing tin roof is quicker than a tiled roof split across three faces. Steep pitches, two storeys and tricky access all add time and safety gear.
Shading from trees, chimneys or a neighbour's second storey can drag down output. Fixing it might mean a different layout or optimisers like Tigo, which add cost but recover output.
Panel layout also matters. East and west split arrays suit homes that use power in the morning and late afternoon, but split layouts may need more mounting and cabling than one big north-facing array.
2. Equipment: panels, inverter and battery
Panels differ in efficiency, warranty and price. We use AIKO, Jinko and Trina. Higher efficiency panels fit more output on a small roof.
The inverter matters as much as the panels. Brand, size, single or three phase, and whether it's battery-ready all change the price. We use Fronius, GoodWe, Sungrow and Sigenergy.
A battery is the biggest add-on. Usable capacity, brand and backup wiring drive the cost, with the federal battery rebate taken off. If you're not ready for one, a hybrid inverter keeps the door open.
Brand choice isn't just about price. Local support, warranty terms and how the inverter, battery and app work together all matter over the life of the system. We'll explain why we've picked each brand on your quote.
Send us a recent bill and a few roof photos. We'll call to talk it through, then send a free, itemised quote with the rebates shown separately.
3. Electrical and site work
- Switchboard condition. Older boards may need upgrading or more safety switches before solar or a battery can go in.
- Single or three phase. SA Power Networks usually limits single phase homes to around 10 kW of inverter.
- Cable runs. A long run from the roof to the switchboard, or to a shed, adds materials and labour.
- Location. We service all of SA, and regional jobs can involve travel.
- SA Power Networks approval should be included, not an extra.
These are the items most often left off cheap quotes and added later. On an older home, ask the installer directly whether they've looked at the switchboard. If they haven't seen it, the price isn't final.
Red flags to watch for
- No brand or model names, just "premium panels" or "tier 1".
- A price given over the phone without seeing your bills or roof.
- Pressure to sign today to "lock in" a rebate.
- No mention of switchboard condition on an older home.
- Rebates lumped into one vague discount.
- No licence number or accreditation on the paperwork.
- Payback or savings promised as a fixed number.
- A battery quoted without saying the usable kWh or what's backed up in a blackout.
Why some quotes are much cheaper
- Different gear. Cheaper panels or an inverter with limited local support.
- Missing scope. Switchboard work, isolators, monitoring setup or SA Power Networks paperwork left off, then added later.
- Undersizing. A smaller system looks cheaper but saves less.
- Corners cut on install. Rushed cabling, poor roof work or no shade planning.
A cheap quote isn't automatically bad, and the most expensive isn't automatically the best. Just make sure you're comparing the same system and the same scope.
4. Rebates and payment
Most home solar gets the federal STC discount, taken straight off the quote. It shrinks a little each year. Batteries get a separate rebate, explained in our solar battery rebate guide.
Both should appear as separate, clear lines on the quote. If a quote shows one lump "rebate" figure, ask how it was worked out. For a battery, it should be based on the usable capacity, and the install date decides the rate.
NG Elec also offers $0 deposit options and flexible payment options. For what real jobs actually cost, see our solar and battery price guide; this guide sticks to how to read and compare the quotes themselves.
What a good solar quote includes
- Your daily usage and how the system size was worked out
- Panel, inverter and battery brands and models, by name
- Expected output, with winter in mind
- Every piece of electrical work, itemised
- SA Power Networks approval
- STC discount and battery rebate as separate lines
- The installer's licence number and accreditation
- Product warranties and the workmanship warranty, in writing
- Payment options, such as $0 deposit
If a quote is missing any of these, ask before you sign. A good installer will be happy to explain.
How to compare quotes fairly
Put your quotes side by side and check each line:
| Check | What to look for |
|---|---|
| System size | Same kW of panels and inverter, sized to your usage |
| Panels and inverter | Brand and model named |
| Battery | Usable kWh, backup scope, brand |
| Electrical work | Switchboard and safety switches itemised |
| Rebates | STC and battery rebate shown separately |
| Approvals | SA Power Networks application included |
| Installer | Licence number, SAA accreditation, insurance |
| Warranty | Product warranties plus workmanship warranty |
Every NG Elec quote is free and itemised, and our installs carry a lifetime workmanship warranty. For what the solar itself costs, see solar panel installation cost in Adelaide.