Most Australian homes today are best suited to a system between 6.6kW and 10kW, while small businesses often need 10kW or more. The right size for you comes down to how much electricity you use, how much roof space you have, your budget, and whether you plan to add a battery or an electric vehicle. This guide works through each of those so you can settle on a size with confidence.
How to work out what size you need
Start with your power bill. Look for your average daily usage in kilowatt hours (kWh), which is usually printed on the bill. A typical Australian household uses somewhere between 16 and 25 kWh a day, though homes with air conditioning, a pool or an EV use a good deal more.
From there, four things shape the decision:
- Energy use: the more you use, especially during daylight hours, the larger the system that pays off.
- Roof space: each panel needs room, so your available roof area sets a practical ceiling on size.
- Budget: a larger system costs more upfront but usually delivers a better long-term return.
- Future plans: if an EV or a battery is on the horizon, sizing up now saves paying for a second installation later.
How much power does each system size produce?
As a rough guide, every 1kW of solar generates around 4 kWh a day across most of Australia. Actual output depends on your location, roof direction, shading and the time of year.
| System size | Approx daily generation | Typically suits |
|---|---|---|
| 5kW | ~20 kWh | Smaller homes, lower daytime use |
| 6.6kW | ~26 kWh | The common choice for average homes |
| 10kW | ~40 kWh | Larger homes, or homes with a battery or EV |
| 13.2kW+ | ~52 kWh+ | Big households and small businesses |
What size solar system for a home?
The 6.6kW system, built from around 15 to 17 solar panels, has been the default for Australian homes for years, and it still suits a lot of households well. Paired with a 5kW inverter, it offers a solid balance of output, cost and rebate eligibility.
Home systems have grown, though. Households running air conditioning, a pool pump or an EV increasingly move to 10kW or larger. If you are adding a battery, a bigger array makes sense so there is surplus daytime generation to store for the evening.
A 6.6kW system generates roughly 26 kWh on an average day, enough to cover most of a typical family home’s usage and cut heavily into grid reliance.
What size solar system for a business?
Businesses usually draw more power and use most of it during the day, which is exactly when solar produces. That makes larger systems, from 10kW up to 30kW or beyond, a strong fit.
The right commercial size depends on your daytime load, your available roof or ground-mount space, and your growth plans. Starting a little larger than today’s needs is often worthwhile if you expect to expand, since it avoids a second install down the track.
Sizing solar and battery together
Batteries have shifted from a nice-to-have to a central part of most new systems, helped by the federal battery rebate that moved to a tiered structure in 2026. Because a battery lets you store daytime solar for use at night, it changes how you size the panels: you generally want enough generation to cover daytime use and still charge the battery.
As a starting point, many homes pair a 10kW array with a battery in the 10 to 13 kWh range, though the right combination depends on your evening usage and budget. Rebate amounts and eligibility change over time, so check the current federal battery rebate details before you commit.
Factors that affect your ideal size
- Roof space and orientation: north-facing roofs produce the most; east and west still work but generate less.
- Daytime versus evening use: high daytime use favours a larger array, while high evening use points towards adding a battery.
- Shading: trees or nearby buildings reduce output and may change where panels are placed.
- Future energy needs: an EV can roughly double a home’s electricity use, so it is worth factoring in early.
Frequently asked questions
What size solar system do most Australian homes get?
A 6.6kW system has long been the most popular choice for average homes. Households with higher usage, a battery, or an EV increasingly choose 10kW or larger.
How much does a 6.6kW solar system produce per day?
Around 26 kWh on an average day across most of Australia, though output varies with location, roof direction, shading and season.
Should I get a bigger system if I plan to add a battery?
Usually yes. A larger array gives you surplus daytime generation to charge the battery, so you rely less on the grid in the evening.
What size solar system does a small business need?
Many small businesses suit 10kW to 30kW, depending on their daytime power use, available roof space and expected growth.
Does system size affect my rebate?
Rebates and eligibility depend on current government programs, which change over time. Check the latest federal and state rebate details before choosing your size.
Get the right size for your home or business
Every roof and power bill is different. The team at Solar National can assess your usage and recommend the right size for your needs. Contact us for a free assessment and custom quote.
