3 kW Solar Systems: Prices And Information
Last Updated: 8th May 2026
A 3 kW solar system was once the most popular size residential solar system in the country, but times have changed and most households choose a much larger system – 6.6 kW or, even better, 10 kW or more; as solar prices have dropped considerably over recent years.
For an average Aussie home, a 3 kW solar system will generate the equivalent of about two-thirds of total electricity usage. But be warned; if you have ducted air-con, a pool pump, and a couple of fridges in your big ol’ house, then it won’t make much of a dent in your electricity bills!
How Much Will a 3 kW Solar System Cost?
At current pricing, you can expect to pay about $3,000-$4,000 for a good 3 kW solar system installed on your roof. This is for a system with quality components, installed by an experienced professional.
How Many Solar Panels Will You Need?
To make up a 3 kW solar system you needed 12 solar panels, assuming that you use 250W panels – but these days much more powerful panels are used; around 440W.
Each 250W panel was approximately 1.6m x 1m, so you needed at least 20 square metres of roof space.
To give you a feel for how big 20 square metres is this picture may help
And here’s what one looks like on a roof:
These days, solar panels are often 440W or larger, so only around 7 are required for a 3 kW solar system:
How Much Electricity Will a 3 kW Solar System Generate?
A 3 kW solar system will generate approximately 12 units of electricity (called kilowatt-hours or kWh‘s) per day. As mentioned, this is about 2/3 of the electricity usage of a modest Australian home.
How Much Cash Will a 3 kW Solar System Earn?
The amount of money you save with a 3 kW system will depend on 2 main factors:
1) When you use the electricity in your home
2) How much much electricity you use.
In fact, (1) is usually a bigger factor than (2). Why? Because the timing determines how much of your precious solar energy goes out into the grid instead of into your home.
If you are intrigued by the whole import/export thing, then you can read about the relationship between exports and payback here.
You can see the payback for a 3 kW system yourself with my solar payback calculator.
How Long Before a 3 kW Solar System Pays for Itself?
If you are not exporting any energy then it will pay back in less than 3 years, assuming you pay 30c per kWh for imported electricity. The more energy you export the longer that stretches out. But the great thing about solar (that can be lost in a simple payback calculation) is this: The monthly cash flows to get your payback can be positive, for many people (depending on how you pay for the system).
Again – this all depends on your individual situation – so if you are keen to explore reducing your overheads with solar energy, I recommend getting 3 quotes from hand-picked, local installers who can work out if solar makes financial sense for you or not.