What determines the size of the solar system I can install?
The size of the solar system that you can install is determined by your available roof space, and if connecting to the grid the limitations of your local power network.
the available roof area that you have to mount the solar panels should be unshaded and facing north, east or west. If your roof gets partial shade you can use microinverters to improve solar system performance. Likewise if you have a south facing roof pitch the angle of the panels can be corrected with the right solar mounting system.
If you don’t have a suitable roof but have space surrounding the house, you can install the solar panels on a dedicated ground mounting system. Although this will always be more expensive as they need to be purpose built.
How much space do solar panels take up?
Solar panels in 2025 come in sizes between 1m-1.2m in width and 1.7m- 2.4m in length depending on the model and power output. Larger solar panels usually have a higher power output.
You will need around 28-30 square meters of space to install a 6.6kW solar system. This can be spread across different areas of your roof. When using more than two different areas of your roof system performance can suffer with some inverters, and system installation costs can go up.
Talk to LuvSolar about the system design that is best for your roof.
Why is 6.6kW a common solar system size?
6.6kW is a common solar system size due to limitations from local networks on the size of the solar system that they will allow to be connected to their grids. This size system size can also fit on the roof of most Australian houses while covering their average energy use.
Most houses are on a single phase power supply, and many power network operators do not allow inverters larger than 5kW to be connected via a single phase supply to their grid without special design features to limit solar export (e.g Essential Energy and Endeavour Energy)
So why 6.6kW and not 5kW?
Solar systems generally provide more consistent energy output, and better value when solar panel capacity is more than the inverter capacity. According to Solar Accreditation Australia’s guidelines a solar inverter must have a power output greater than or equal to 75% of the capacity of the solar panels connected to it. This means that a 5kW inverter can have up to 6.6kW of solar panels connected. (If a battery is also connected in which case the inverter manufacturer limits apply – LuvSolar also supply fully integrated solar batteries read what you need to know about home solar batteries here)
For the reasons above, 6.6kW has become the default standard solar system size offering for single phase connections.
How many solar panels for a 6.6kW system?
The number of solar panels needed for a 6.6kW system in 2025 is between 10 and 16 depending on the power rating of the solar panels used. Larger panels are now the norm with 415W solar panels now common place.
How much solar will my local power network allow
Most Australian customers will be allowed to connect a 10kW inverter to the grid and so will be able to install 13.3kW of solar panels if they have the roof space.
However, the amount of solar your local power network will allow you to connect to their network will depend on:
- The policies of your local power network (e.g. Ausgrid, Endeavour Energy, Essential Energy)
- Where you are located in your local power network
- Whether your connection is single phase of three phase
- Whether your solar system is designed to limit power export to the local network
- For larger commercial power users – The specifications of your existing connection
- For larger commercial power users – Whether the system design includes secondary grid protection systems
What is the difference between a single phase and a three phase connection?
Traditionally in power networks, electricity has been generated in large rotating generators and comes out as three separate supplies (phases). This is known as “Three-phase power”.
There are basically three separate lines that carry power right from the generator in the power station all the way to the small transformers that you can see on telegraph poles in residential streets.
You can often see the three phases in the three distinct connections to transformers, or in the three wires (and the neutral lines) in the above ground power supply in many suburban streets. Many houses just connect to one of these wires for the mains power supply. Although some connect to all three, so can draw much more power from the grid.
When it comes to the electricity connection in your home, you will either be connected to 1, 2, or 3 of these phases, (but it’s mainly 1 or all 3).
Why are there limits on how much solar I can install on my roof?
For local power networks to be able to function efficiently, power flows need to be balanced across all 3 phases.
Where houses are on a single phase in a street, each house gets connected to one of the three phases alternating as you go down the street.
If any one solar customer has too large of a solar system exporting on a single phase, then this can unbalance the power flows on the network, causing problems for its efficient operation.
If you are connected to a three phase supply you will be able to connect a bigger solar system. Larger commercial three phase customers can also connect more than houses connected to three phase although the connection application process will be more involved.
Can I install a 10kW system on a single phase connection?
Yes, unless you are in Perth, the Northern Territory or some parts of the ACT, you can install 10kW on a single phase connection. However, most networks will require you to limit the amount of power that your system exports to the grid. This will require the use of a separate meter that connects to your inverter turning it down if the system is exporting more than the network limit.
If you want to know more about system sizing, get in touch for a free no obligation consultation and quote. We’d love to hear from you!
