☀ Solar & Battery Sizer

Upload your energy use, tell us about your roof, and get a right-sized solar & battery recommendation. Tuned for the Sunshine Coast & Queensland.

Build v3 · reads Energex/Ergon & NEM12 files · works offline with built-in Australia-wide sun data

1 Location

Your location sets the amount of sunshine your roof receives (real satellite data from NASA POWER).

Suburb / address

Latitude

Longitude

Default set to the Sunshine Coast. Type an address and press Find, or enter coordinates directly.

2 Roof pitch & orientation

Which way the roof faces and how steep it is changes output. In Queensland, north-facing is best.

Roof pitch — any angle (degrees)

Usable roof area (optional)

Roof facing — exact bearing (° from North: 0=N, 90=E, 180=S, 270=W)

Type an exact pitch and bearing, or use the presets/compass as shortcuts. Have panels on two roof faces? Pick your main/largest one for now.

3 Your energy use

Upload a usage file from your electricity retailer, or just enter your bill figures.

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Drop your CSV here or tap to choose

Works with retailer usage exports & AEMO NEM12 files (AGL, Origin, Energy Australia, Ergon…). We read date + kWh columns.

Daytime vs night usage (used when you don't upload interval data)

Share of electricity used during daylight (approx): 30%

Most homes use ~25–35% of power in daylight (when solar is generating). If you upload an interval/NEM12 file, your real hour-by-hour profile is used instead and this is ignored.

4 Tariff & time targeting

Pick a flat rate, or set time-of-use bands and choose which hours to offset. Untargeted hours (e.g. cheap overnight power) are deliberately left on the grid, so the battery is sized only for the hours worth covering.

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Upload a bill (PDF) to auto-fill your tariffs

Read locally in your browser — nothing leaves your device. Works with text-based PDFs (AGL, Origin, EnergyAustralia…). Always check the figures.

Tariff bands — set the rate and tick which to offset

Feed-in tariff (c/kWh)

Assign your day — pick a band, then click the hours

Let cheap off-peak grid top up the battery when solar is short (e.g. winter) Charges the battery from your cheapest untargeted hours — but only by the shortfall solar won't cover, so it helps on low-sun days and does nothing when it's sunny. Off = the system is self-reliant, so the array is sized a little larger to carry the battery's charging losses itself; on = cheap grid carries them, so the array can be slightly smaller.

5 Assumptions (edit anytime)

Sensible Queensland defaults — change them to match your quotes and tariffs.

Target offset of targeted use (%)

Daily supply charge (c/day)

Battery round-trip efficiency (%)

Blackout reserve kept in battery (%)

Battery capacity left after 10 yrs (%)

Panel output left after 10 yrs (%)

Battery warranted cycles

Panel wattage (W) — count & area only

The supply charge is a fixed daily grid fee you pay regardless of solar (it doesn't change your savings, but is shown in your before/after bill). Panel wattage only affects the estimated panel count and roof area — not the system size or output. Degradation: both the panels and the battery are sized so their year-10 capacity still meets your needs — defaults follow the Jinko Tiger Neo warranty (~95.4% output at 10 yrs) and a typical battery warranty (80% at 10 yrs); adjust to match your hardware. For system pricing and payback, use the quote checker below with a real installer quote.

✅ Recommended system

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kW of solar

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kWh usable battery

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Est. yearly generation

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Your yearly use

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Bill offset

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Yield at your roof

📈 Monthly solar generation

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💰 Savings estimate

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Saving in year 1

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Self-consumed

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10-yr total savings

For system pricing and payback, get installer quotes and run them through the quote checker below — payback there uses the quote’s real price with degradation applied year by year.

⚠️ These are planning estimates only, generated from modelled sunshine and typical assumptions — not a formal quote or financial advice. Actual output, pricing and rebates vary. Always get accredited installer quotes (CEC-accredited) before buying.

🔍 Check an installer's quote

Upload a quote (or type its figures) and we'll run the same honest, seasonal economics on that exact system — using your usage, tariff and location — so you can compare the installer's claims with the modelled reality. Click "Calculate my system" above first so we have your data.

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Upload a quote (PDF) to auto-fill the figures

Read locally in your browser. We look for the system size, battery and price — always check them.

Solar in the quote (kW)

Battery in the quote (kWh usable)

Inverter in the quote (kW, optional)

Quoted price ($)

STC rebate ($) — if not already off the price

Installer's claimed saving ($/yr, optional)

Installer's claimed payback (yrs, optional)

Home-loan rate the money would otherwise offset (%)

📬 Want this priced properly?

Leave your details and we’ll email you this report and have a vetted local installer price the exact system — no obligation, and your files never leave your browser (only the summary numbers are sent).