Solar calculator for Melbourne homes
Enter your power bill and see the system size that fits, what it could save each year, and whether a battery makes sense. Then, if you want, get a free design and quote for your roof.
Updated November 2026 · Litmec Electrical, REC-10383
Most Melbourne homes paying $350 to $600 a quarter for power suit a 6.6 kW to 10 kW solar system. A 6.6 kW system on a north-facing Melbourne roof makes about 9,500 kWh a year, or 26 kWh a day on average.
The calculator below sizes from your own bill. It uses a slightly conservative output figure, so a typical roof with some east or west panels and a little shade still meets the estimate.
Check your bill
A few quick questions. See the system that fits and what it could save. No sign-up to see your result.
Building a new home? Skip the bill and send us your plans
What size solar system do I need in Melbourne?
Size follows how much power you use, not the size of your house. The calculator takes your bill, removes the daily supply charge (which solar can't touch), and works out your daily use at about 30c per kWh. It then picks the smallest standard system that covers that use with roughly 10% to spare.
| Quarterly bill | Daily use | Solar size | Yearly saving, solar | Battery | Yearly saving, solar + battery |
|---|---|---|---|---|---|
| $250 | 5 kWh | 6.6 kW | $400–550 | Probably not yet | $600–800 |
| $350 | 9 kWh | 6.6 kW | $500–700 | 5 kWh | $750–1,050 |
| $450 | 13 kWh | 6.6 kW | $600–800 | 10 kWh | $1,000–1,400 |
| $600 | 18 kWh | 6.6 kW | $700–1,000 | 10 kWh | $1,250–1,700 |
| $800 | 26 kWh | 8 kW | $950–1,300 | 15 kWh | $1,750–2,400 |
| $1000 | 33 kWh | 10 kW | $1,200–1,650 | 20 kWh | $2,250–3,100 |
| $1300 | 44 kWh | 10 kW | $1,450–2,000 | 20 kWh | $2,500–3,450 |
Two things stand out. First, below about $300 a quarter most of the bill is supply charge, so solar saves less than people expect. Second, the step from 6.6 kW to 10 kW only pays when you use the extra power yourself, because exported solar earns a few cents per kWh at most in Victoria. See why the feed-in tariff matters.
How the calculator works
- Your use: bill minus supply charge, divided by your rate. If you enter the kWh from your bill, it uses that instead.
- Output: 3.55 kWh per kW of panels per day, averaged over the year. A perfect north-facing roof does about 3.94 (PVGIS), so the calculator leaves room for real roofs.
- Who's home in the day: decides how much solar you use directly. The rest goes into a battery, or is exported at about 4c per kWh.
- Batteries: sized to about 80% of your night-time use, and discounted for winter days when they don't fill.
- Upcoming loads: an electric car adds about 6 kWh a day, a pool pump 4, and moving off gas about 6.
Why there's no price
The price depends on your roof, your switchboard, single or three phase, and the equipment that suits you. A price from a web form is a guess, and guesses on solar are usually wrong in the customer's favour until install day. A proper quote comes after an installer has seen your roof, with every component by make and model and each rebate on its own line.
Single-phase limits
Most Melbourne homes are single phase. Distributors usually cap a single-phase system at around 10 kW of inverter with exports limited to 5 kW, so the calculator stops at 10 kW unless you tell it you have three phase. More on single vs three phase.
Related
Questions
What size solar system do I need for a $500 quarterly bill?
A $500 quarterly bill in Melbourne is roughly 15 kWh a day, which suits a 6.6 kW system for most single-phase homes. Who is home during the day and any electric car or move off gas can push that up.
Is 6.6 kW enough for a family home in Melbourne?
For many households, yes. 6.6 kW of north-facing panels makes about 9,500 kWh a year in Melbourne, more than a typical family uses. Larger families, pools, electric cars and all-electric homes often justify 8 to 10 kW, or more on three phase.
How accurate is an online solar calculator?
It is a starting point. Roof direction, shading, your tariff and when you use power all change the result. The calculator uses Melbourne averages; a written quote after a site visit uses your roof and your bill.
Does the calculator store my details?
No details are needed to see a result. Only if you send us your details do your answers arrive with them, so whoever helps you knows what you saw.
Check it on your roof
One minute online, then a free visit from a licensed electrician who checks your roof and switchboard.