How Many Solar Panels Do I Need To Power My Home?
By Solar Energy Adelaide | 18 March 2025
Looking into solar for your home? One of the first questions most people ask is:
How many solar panels do I actually need?
It’s a great question—after all, you don’t want to install too few and miss out on savings, but you also don’t want to overspend on a system that’s bigger than necessary.
The right answer depends on your home, your energy habits, and your future plans.
A decade ago, when solar was much more expensive, most Adelaide homes installed small systems—between 1.5kW and 3kW. But times have changed. Solar is now more affordable, technology has improved, electricity prices have skyrocketed, and we’re using more power than ever. Today, the average solar system size sits between 6.6kW and 13kW.
But solar isn’t a one-size-fits-all solution. The number of panels you need will depend on factors like:
✅ Your current electricity usage – How much power does your home use daily?
✅ Your future energy needs – Planning a home extension, EV, or working from home?
✅ Battery storage – If you want a battery now or in the future, this affects system size.
✅ Panel efficiency – Not all solar panels generate the same amount of power.
✅ Available roof space – More space allows for a bigger system, but efficiency matters too.
✅ Your energy goals – Want to slash your bills or eliminate them completely?
In this guide, we’ll break down exactly how to calculate the number of solar panels you need and help you figure out what system size is the best fit for your home.
👉 Looking for the best solar panels in Adelaide? Read our review on the best solar brands here.
1. How Much Electricity Does Your Home Use?
The first step in determining the number of solar panels you need is checking your electricity bill.
Look for your average daily electricity consumption, which is measured in kilowatt-hours (kWh).
🔹 Small household (low energy use): 10 kWh per day → A 6.6 kW system may be sufficient.
🔹 Medium household (moderate energy use): 20 kWh per day → A 10 kW system is recommended.
🔹 Large household (high energy use): 30+ kWh per day → A 13.3 kW system or larger may be needed.
💡 Tip: If your electricity usage is expected to grow—such as adding an electric vehicle, pool, air conditioning or perhaps a family member will likely be home more often — it’s smart to design your solar system for your future power usage, not just your current power usage. This will save the cost & hassle of adding panels in the future.
2. Do You Plan to Install a Battery?
A solar battery allows you to store excess solar power that you have generated during the day and use it at night or during peak periods when electricity costs are at their highest.
Whether solar, or solar battery is the best option for your home is really dependant on how and when you use your electricity.
If you are retired, or working from home and have the ability to run high powered appliances during daylight hours, then you will likely do excellent with a large solar system.
A person that is at work during the day and runs high powered appliances in the evening would see great financial benefit from a smaller solar system combined with a solar battery.
If you are a person that wants to eliminate your electricity bills, a large solar system combined with a battery will be the best option for you.
💡 Batteries allow you to gain energy independence, protect you from peak-rate electricity costs, and act as a backup power generator in case of blackouts. However, they do add to the upfront cost, so it’s important to get expert advice on whether a battery is beneficial for you.
Solar systems can be installed in a way so that a battery can easily be added in the future.
3. How Many Solar Panels Do I Need?
Solar panels vary in size and efficiency, but most modern pv panels produce between 440W and 475W per panel.
Here’s a guide to how many panels you may need for different system sizes:
System Size | Number of Panels (Based on 440W-475W panels) | Estimated Daily Output (in kWh) |
6.6 kW | 14–15 panels | 24–28 kWh |
10 kW | 22–24 panels | 38–44 kWh |
13.3 kW | 29–30 panels | 50–55 kWh |
🔹 Smaller households with efficient energy use may only need a 6.6 kW system.
🔹 Larger households or those with higher energy needs may benefit from a 10 kW or 13.3 kW system.
💡 Keep in mind: The actual power output of your system will depend on factors like the efficiency rating of your solar panels, roof orientation, shading, and weather conditions. When you receive a quote from a solar installer, it should clearly summarise your expected daily solar production, as well as your estimated electricity cost savings so you know how solar will work for you.
4. How Much Roof Space Do You Have?
Each solar panel takes up about 1.7m²-1.9m². You’ll need to ensure your roof has enough space for the system you choose.
Here’s an estimate of how much space you’d need for different system sizes:
System Size | Number of Panels | Estimated Roof Space Required |
6.6 kW | 14–15 panels | 23–25m² |
10 kW | 22–24 panels | 36–40m² |
13.3 kW | 29–30 panels | 48–51m² |
🔹 If your roof space is limited, you can opt for high-efficiency panels, which generate more power per panel, reducing the total number of panels required. REC panels have the highest efficiency rating for solar panels and have long held the top position for premium solar panels. Their wafer cell technology, durability and low degradation rate make them ideal for roofs with limited space or shading issues.
🔹 If shading is a concern you can still maximise your solar panel power output by using micro-inverters such as Enphase micro inverters, or SolarEdge DC Optimised systems. These systems will allow panels to perform to their peak output when shading is an issue while also coming with a host of excellent features, & industry leading warranties.
So, What’s the Right Size Solar System for You?
Choosing the right solar system depends on your current and future energy needs, your budget, and whether you plan to install a battery.
Here’s a quick guide to help you decide:
✅ If you want to reduce your power bill but don’t use much energy → A 6.6 kW system may be enough.
✅ If you have high energy usage or plan to add a battery later → A 10 kW system is a good option.
✅ If you want to future-proof your home and have the roof space → A 13.3 kW system will provide maximum savings and flexibility.
How Much Can You Save With Solar Panels?
On average, a well-sized solar system can reduce a household’s electricity bill by 60–90%. Adding a battery can further increase savings and give you more energy independence.
💡 Government Rebates & Incentives
The Australian government offers solar rebates and incentives, which can significantly reduce the cost of installing a solar system. These rebates depend on two factors, system size and location, so it’s worth checking what’s available in South Australia.
Find out everything you need to know on Solar Government Rebates for South Australia in 2025 here.
💡 Solar Financing with Green Loans
Financing your solar with Green Loans has also become a popular choice. These low interest loans designed specifically for renewable energy investments allow you to make the switch over to solar with $0 upfront. For many, the cost of their Green Loan repayments works out less than what they had been paying on their electricity bills.
Read more about what the best pathway is for you to get solar installed on your roof sooner with simple solar financing.
Get Expert Advice on Your Solar System
Every home is unique, and the best way to determine the right number of solar panels is by getting a personalised assessment.
At Solar Energy Adelaide, we specialise in:
✅ Custom solar system design tailored to your energy needs
✅ High-quality solar panels and battery storage solutions
✅ Professional installation by experienced local solar experts
✅ Ongoing support, advice, maintenance, and repairs
💡 Want to find out how much you can save with solar?
📞 Contact us today for a free consultation and quote!
Local, Trusted, and Here to Help – Adelaide’s Solar Experts
As a local business here in Adelaide, South Australia, we have built our reputation on family values of trust, transparency and education.
We place our focus on you, the customer to ensure you receive a solar or battery installation of the highest quality and one that will serve you well into the future.
Knowledge is power. To make an informed decision about exactly how solar can benefit you, we offer free, in-person solar consultations. This allows us to assess your energy needs and present you with customised solar and battery solutions tailored to your current and future energy needs.
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Solar power has become a staple for South Aussie homes and businesses.
With rising electricity costs, solar panel installation offers long term savings and financial security with minimal maintenance and solar rebates available.
Ready to gain energy independence? Dreaming of a day with a $0 power bill?
With a solar battery for your home or business, you can store your excess energy and use it when you need it most.
Solar battery storage has become more affordable in recent years and can even be added to most existing solar systems.
Worried your solar system is underperforming?
If your solar system is not covering between 60-90% of your energy needs there is likely a problem that needs attention.
Our skilled technicians handle all aspects of solar system servicing, including solar panel repairs, solar inverter repairs and solar warranty assistance.