The short answer: most Melbourne homes suit a solar system of 6.6 kW to 10 kW. As a rule of thumb, a household using 15–20 kWh a day suits around 6.6–8 kW, and homes using 25 kWh+ a day — or planning a battery or electric car — suit 10 kW or more.
The right size for you depends on four things: how much power you use, when you use it, your roof, and your export limit.
Quick sizing table
| Daily power use | Typical household | Suggested system |
|---|---|---|
| Under 12 kWh | 1–2 people, gas heating and cooking | 5–6.6 kW |
| 12–20 kWh | Small family | 6.6–8 kW |
| 20–30 kWh | Larger family, some electric heating/cooling | 8–10 kW |
| 30 kWh+ | All-electric home, pool, EV or battery | 10–13 kW+ |
A starting point only — we size every system from your actual bills and roof.
Step 1: Find your daily usage
Your electricity bill shows your usage over the billing period, usually in kWh. Divide it by the number of days to get your average daily use. Check a summer and a winter bill if you can — many Melbourne homes use far more in winter.
Step 2: Know what solar produces in Melbourne
On average across the year, each 1 kW of solar panels in Melbourne produces about 3.5 kWh per day. That varies a lot by season:
| Per 1 kW of panels | A 6.6 kW system | A 10 kW system | |
|---|---|---|---|
| Summer day | ~4.5–5.5 kWh | ~30–36 kWh | ~45–55 kWh |
| Yearly average | ~3.5 kWh | ~23 kWh | ~35 kWh |
| Winter day | ~1.5–2 kWh | ~10–13 kWh | ~15–20 kWh |
Typical north-facing output in Melbourne. East/west roofs produce a little less in total but spread production across the day; shading reduces output.
Step 3: Think about when you use power
Solar only directly powers your home while the sun is up. Since Victoria’s regulated minimum feed-in tariff ended in July 2025, exported power often earns only a few cents per kWh, so the goal is to use as much of your solar as possible:
- If you’re home during the day, more of your solar is used directly — a mid-sized system pays back fast
- If you’re out all day, you’ll export more — consider shifting appliances to daytime with timers, or adding a battery
- If you plan to charge an EV, daytime charging from solar is the cheapest fuel you can get
Step 4: Check your roof and export limit
- Roof space: each modern panel is roughly 2 m² and 440–480 W, so a 6.6 kW system needs about 14–15 panels and 30 m² of usable, mostly unshaded roof.
- Orientation: north is best; east and west work well; south-facing roofs are less productive in Melbourne.
- Export limit: your electricity distributor sets how much your system can export. Many single-phase homes are limited to around 5 kW. You can still install more panels — the extra is used in your home or stored in a battery.
- Inverter oversizing: panels can be up to 133% of your inverter capacity and still qualify for STCs — which is why a 6.6 kW array on a 5 kW inverter is so common.
Step 5: Plan for a battery or EV now
If you’re likely to add a battery or an electric car in the next few years, size your solar for it now. Adding panels later means a second install and often a second inverter. A battery-ready hybrid inverter can also save money down the track — see is a home battery worth it in Victoria?
The bottom line
Don’t buy the biggest system you can fit, and don’t buy the cheapest package on offer. Size it to your usage, your roof and your plans — that’s what gets the fastest payback. See how much solar costs in Melbourne, or get a free quote and we’ll design a system around your actual bills.
Sources
- Clean Energy Council — guide to installing solar for your home
- Clean Energy Regulator — Small-scale Renewable Energy Scheme
- Solar Victoria — solar panel rebate
General information only — your system size is confirmed after a site assessment.
