As electricity prices continue to soar across Australia, more homeowners are turning to solar power to reduce their energy bills and gain independence from the grid. Among the most popular choices for residential installations are the 10kW solar system and the 5kW system. But how do you know which one suits your household better?
This article compares both systems side by side to help you decide based on your power needs, available roof space, budget, and long-term plans.
☀️ Understanding Solar System Sizes
Solar system capacity is measured in kilowatts (kW), representing the maximum power the system can generate under ideal conditions. The bigger the system, the more electricity it can produce. But bigger isn’t always better—your energy usage habits and roof size matter too.
🔋 What Is a 10kW Solar System?
A 10kW solar system is considered a high-capacity residential system, capable of powering large households or small businesses.
Key features:
-
Average daily output: 38–44 kWh
-
Number of panels: 25–28 (assuming 370–400W panels)
-
Roof space required: 50–65 m²
-
Estimated cost: $8,000 to $14,000
Who it’s for:
-
Homes with high daytime usage (e.g., pool pumps, EV charging, multiple appliances)
-
Families of 5+ members
-
Remote work setups with multiple devices running all day
A 10kW system is an investment that not only covers heavy usage but also lets you export extra electricity to the grid, earning credit via feed-in tariffs.
💰 How Much Can You Save?
With a 10kW solar system, average households can save $3,000 to $5,000 per year, depending on location, sunlight exposure, and local feed-in rates. The payback period usually falls between 4 to 6 years, after which the system produces near-free power for the next 15–20 years.
⚖️ Pros and Cons of a 10kW Solar Setup
✅ Pros:
-
Supports heavy power loads
-
Higher long-term savings
-
Ideal for battery integration and future-proofing
❌ Cons:
-
Higher upfront cost
-
Needs more roof space
-
May produce excess power you don’t use without a battery
🔆 What About a 5kW Solar System?
For average-sized homes in Australia, a 5kW solar system is a solid and budget-friendly option.
Key features:
-
Average daily output: 18–22 kWh
-
Number of panels: 12–15
-
Roof space required: 25–35 m²
-
Estimated cost: $4,000 to $7,000
Who it’s for:
-
Small to medium families
-
Budget-conscious buyers
-
Households with lower energy needs
A 5kW system typically covers 60–80% of the power needs of a standard Australian home, depending on usage patterns and efficiency.
🧾 Government Incentives and Rebates
Both 5kW and 10kW systems qualify for the Small-scale Renewable Energy Scheme (SRES), which offers STCs (Small-scale Technology Certificates) to reduce upfront costs.
Additionally, you can benefit from state-based solar rebates, especially if you live in NSW, VIC, SA, or QLD.
📉 Comparing the Two Systems
| Feature | 10kW Solar System | 5kW Solar System |
|---|---|---|
| Daily Output | 38–44 kWh | 18–22 kWh |
| Cost (AUD) | $8,000–$14,000 | $4,000–$7,000 |
| Roof Space | 50–65 m² | 25–35 m² |
| Household Size | Large (5+ members) | Small to medium (2–4 members) |
| Battery-Ready | Yes | Yes |
| Payback Period | 4–6 years | 2–4 years |
🧠 How to Choose the Right Solar System for You
-
Check your power usage
Look at your electricity bills for average daily consumption. If you use 30 kWh or more daily, a 10kW system may be ideal. If it’s around 15–20 kWh, a 5kW system might suffice. -
Think about future energy needs
Planning to add an EV charger? A pool heater? Or working from home more often? Consider going bigger to accommodate future usage. -
Assess your roof size and direction
North-facing panels perform best in Australia, but east/west orientation also works. Make sure you have the space for the number of panels needed. -
Budget and financing
While the 10kW system offers higher savings long-term, the 5kW system has a quicker ROI and is easier to afford upfront.
🌱 Environmental Impact of Each System
-
A 10kW system can offset 12–14 tonnes of CO₂ annually
-
A 5kW system offsets around 6–7 tonnes per year
Regardless of size, both systems significantly reduce your carbon footprint and contribute to Australia’s clean energy goals.
Final Thoughts
When deciding between a 10kW and 5kW solar system, there’s no universal answer. It all comes down to your household’s energy habits, available roof space, and financial plans.
