Solar System Sizes Explained: 6.6kW, 10kW and More
Choosing the right solar system size for your home or business is one of the most important steps when making the switch to renewable energy. In Australia, 6.6kW and 10kW solar systems are two of the most popular options for residential installations, each catering to different energy needs, roof sizes, and budgets.
At Ballarat Solar Panels, we’re here to make it simple. Whether you’re a first-time solar buyer or planning to upgrade your current setup, this guide will help you understand your options and choose the right solar system for your needs.
What Does Solar System Size Mean?
The size of a solar system refers to the total power output of all the panels combined, measured in kilowatts (kW). For example:
- 1 kilowatt (kW) = 1,000 watts
- A system with 15 x 440W panels equals a 6.6kW system
Your system size determines how much solar electricity you can generate each day, which directly impacts your savings on energy bills.
6.6kW Solar Systems: The Aussie Favourite
Why It’s Popular
The 6.6kW solar system is a popular choice for Australian households because it offers a great balance of affordability, roof space efficiency, and energy production. It is paired with a 5kW inverter which is the most efficient and cost effective inverter size for a solar installation of 6.6kW. Batteries are easily added to existing 6.6kW systems without increasing the number of panels to offer homeowners increased use of their solar investment.
System Specs
- Panels: 15 (440W each)
- Roof Space Needed: 30–35 m²
- Daily Output: 24–27 kWh/day (depending on location)
- Inverter: 5kW
Best For
- Homes with 2–4 occupants
- Moderate daily electricity use (20–25 kWh/day)
- Properties with limited roof space
- Budget-conscious homeowners
10kW Solar Systems: Power for Larger Households
Why Choose a 10kW System?
If your energy usage is high—maybe due to a larger family, electric vehicles, or running a pool or spa—then a 10kW system could be your best bet. It also provides the flexibility to add a battery or future-proof for new appliances. Batteries are also easily able to be added to 6.6kW systems with fantastic return for homeowners.
System Specs
- Panels: 24 (440W each)
- Roof Space Needed: 45–50 m²
- Daily Output: 38–44 kWh/day
- Inverter: 8kW–10kW
Best For
- Homes with 4+ people
- Daily energy use of 30–40 kWh
- EV owners or high daytime usage
- Homes with larger roof space
Size Comparison: 6.6kW vs 10kW Solar Systems
| Feature | 6.6kW System | 10kW System |
|---|---|---|
| Number of Panels | 15 | 24 |
| Energy Generation (Daily) | 24–27 kWh | 38–44 kWh |
| Roof Space Required | 30–35 m² | 45–50 m² |
| Inverter Size | 5kW | 8kW–10kW |
| Ideal Household Size | 2–4 people | 4+ people |
| Battery Compatibility | Yes | Yes |
| Export to Grid | Yes | Yes |
| ROI & Payback Period | 3–5 years | 4–7 years |
Key Factors When Choosing a System Size
Before deciding between a 6.6kW or 10kW system, consider:
✅ Your Energy Usage
Review your energy bills to check your average daily usage in kWh. Most Aussie households use 11–23 kWh/day, but your needs may increase with time.
✅ Available Roof Space
Measure your usable sunny roof area. Panel layout and orientation can affect how many panels will fit.
✅ Your Budget
A 6.6kW system is more affordable upfront. A 10kW system costs more but delivers higher savings over time—especially if paired with battery storage.
✅ Future Plans
Planning to install an EV charger, switch from gas to electric, or add a pool heater? A larger system may make more sense long-term.
✅ Electricity Pricing & Feed-in Tariffs
If your retailer offers a strong feed-in tariff, exporting excess energy from a larger system (like 10kW) can boost your return.
Don’t Forget the Inverter Size
Don’t Worry About Inverter Sizing — That’s Our Job
Inverters are a crucial part of your solar system, converting the electricity generated by your panels into usable power for your home. It’s common (and completely compliant) for a 6.6kW solar system to be paired with a 5kW inverter. This setup works well because most single-phase homes in Victoria are limited to exporting a maximum of 5kW to the grid.
While there are technical rules around how much panel capacity can be installed relative to the inverter size (called inverter oversizing limits), this is something your solar designer or installer will handle to ensure your system is compliant and eligible for government rebates.
Need Help Deciding?
Choosing the right system size is about balancing your energy needs, space, and future goals. That’s where we come in.
✔️ Ballarat Solar Panels offers expert solar advice, system design, and obligation-free quotes.
✔️ We use specialist solar software to assess your usage, roof size, and budget to design the most efficient and cost-effective system for your home or business.
Get a Free Quote Today
Not sure which solar system is right for your home?
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