How Many Solar Panels Do I Need for My House in Melbourne?
The simple formula, a free interactive calculator, and real Melbourne examples — work out exactly how many panels your home needs in under a minute.
Most Melbourne homes need 16 to 24 solar panels. As a simple rule of thumb: divide your average daily electricity usage (kWh) by 1.6 — the typical daily output of a modern 430-440W panel in Melbourne after system losses. For example, a home using 26 kWh a day needs roughly 16 panels (a 6.6kW system), while a home using 40 kWh a day needs roughly 24 panels (a 10kW system).
The Simple Formula
Every solar quote ultimately comes back to one calculation: how much electricity do you use, and how much can each panel realistically produce in Melbourne? Once you know both numbers, the panel count is simple division.
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The 1.6 kWh/day figure is Supply Solar’s real-world Melbourne average across 415-440W panels, factoring in inverter efficiency, wiring losses, and seasonal variation — not just a manufacturer’s lab rating.
Where does 1.6 kWh per panel come from? It’s derived directly from installed systems: a 6.6kW system with 16 panels produces about 26 kWh/day in Melbourne (26 ÷ 16 = 1.625), and a 10kW system with 24 panels produces about 40 kWh/day (40 ÷ 24 = 1.67) — consistent across every standard system size we install.
Panels by Household Size
| Household | Typical Daily Use | Panels Needed | System Size |
|---|---|---|---|
| 1-2 people, small home | ~12-16 kWh | ~8-10 panels | ~3-4kW |
| 1-3 people, small family | ~26 kWh | ~16 panels | 6.6kW |
| 3-5 people, family home | ~40 kWh | ~24 panels | 10kW |
| 4-5 people, high-use home | ~52 kWh | ~31 panels | 13kW |
| Large home, EV or business | ~80 kWh | ~48 panels | 20kW |
Real Melbourne Worked Examples
Example 1 — Young family, 3 bedrooms, Cranbourne
Example 2 — Family of 4 with ducted air conditioning, Berwick
Example 3 — Large household with pool + planning an EV, Frankston
Where to find your daily usage
Your electricity bill shows total kWh used for the billing period, usually 90 days (quarterly) or 30 days (monthly). Divide the total by the number of days to get your average daily usage — the most accurate input for this calculation.
What Changes the Number
The formula gives a strong estimate, but four real-world factors adjust the final panel count:
- Panel wattage. Higher-wattage panels (440W vs 415W) mean fewer panels for the same system size. We use current Tier 1 panels rated 415-440W.
- Roof orientation and shading. A north-facing, unshaded roof gets the full 1.6 kWh/panel/day. East or west-facing roofs, or roofs with chimney or tree shading, produce somewhat less per panel — sometimes requiring one or two extra panels to compensate.
- Inverter sizing and clipping. Installers commonly oversize the panel array slightly relative to the inverter (DC/AC ratio) to capture more morning and afternoon generation, which can shift panel counts up slightly.
- Future-proofing. If an EV, battery, or all-electric switch is likely, sizing a few panels above your current usage is usually more cost-effective than a second installation later.
Want your exact panel count?
A free site assessment measures your real roof, shading and usage — no guesswork.
