When Aussies start looking into solar, something magical happens: every person you’ve ever met suddenly becomes a seasoned electrical engineer. Your mate you bump into at Bunnings tells you he “reckons 5 kW is heaps.” Your brother-in-law, who once wired a caravan light the wrong way around, insists you need “a mega system—like 20 kW, trust me.”
And then there’s Google… overflowing with graphs, charts, and advice that contradict each other faster than a group of politicians before an election.
So let’s clear the fog and get practical.
Before choosing a solar system size, you’ve got to know how much energy your home uses each day. You’ll find this on your electricity bill under kWh per day.
A general guide:
Your usage is your starting point. Not your neighbour’s, not your coworker’s and definitely not that guy on Facebook Marketplace offering “premium 6.6 kW installs for $2,999 cash.”
Let’s break this down without the jargon.
Think of it like a water tank:
Big tank, more potential. Small tank, less potential. No need to complicate things.
Solar system sizes have changed a lot in the last decade. There were times when people thought a 3 kW system was “massive” and they’d brag about it at weekend barbecues? These days, that’s the solar equivalent of hanging onto your old Nokia brick “because it still works.” Good for nostalgia, not so great for modern energy needs.
Why the modern sweet spot starts at 6.6 kW
Most Australian homes today land somewhere around the 6.6 kW mark as their baseline. Not because it’s trendy, but because:
Think of 6.6 kW as the new “standard home size” — not over the top, not underdone. It simply works.
When you shouldn’t settle for 6.6 kW
Many households now use far more electricity than they did even five years ago. Between multiple TVs, air-con, appliances, laptops, chargers, pumps, heated towel rails and that second fridge in the garage that never seems to turn off… power usage creeps up.
You’ll want to consider 8–10 kW or more if:
In these cases, a larger system isn’t “excessive” — it’s strategic. Kind of like buying a slightly bigger esky because you know more people are turning up than originally RSVP’d.
So what’s the real goal?
Pick a system size that won’t just handle today’s needs, but will still perform well as your home evolves. Installing too small often leads to “solar regret,” and no one wants to be the person saying, “We should’ve gone bigger,” every time the power bill arrives.
Batteries are brilliant — especially as households electrify.
But here’s the catch: batteries love big solar systems.
A battery without enough solar feeding it is like buying a big esky but forgetting to pack the ice.
More solar =
Even if you’re only considering a battery for the future, oversizing the solar system now saves headaches (and extra installation costs) later.
No two Aussie roofs are the same. Some are wide open and sun-soaked. Others are a puzzle of pitches, gables and TV antennas installed by someone who clearly wasn’t thinking about solar panels at the time.
When designing your system, a good installer will assess:
Solar is not “one size fits all.” A well-designed layout can outperform a larger poorly laid-out system — design matters more than most people realise.
Daytime homebodies:
Perfect solar candidates — your usage matches production.
→ 6–8 kW usually ideal.
Out during the day, home at night:
You’ll need more solar, or solar + battery.
→ 8–10 kW+ recommended.
EV owners or future EV owners:
Charging a car at home adds a lot of load.
→ 10–15 kW is smart.
Going all-electric:
Induction cooktop, heat pump hot water, reverse-cycle heating…
→ Oversize the system to future-proof.
The best solar systems:
Good solar isn’t just about generating power — it’s about designing a system that fits how you live.
This won’t replace a proper design, but it gets you in the ballpark.
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If you’re comparing quotes and one is suspiciously cheap — so cheap your eyebrow raises on its own — trust that instinct. As Dad would say, “If someone’s selling you a brand-new barbecue for fifty bucks, mate, it’s either stolen or it’s going to fall apart before the sausages are cooked.”
Cheap solar usually means:
That’s exactly why quality-minded households choose Solar Fusion Solutions. We don’t do cheap-and-nasty. We design properly engineered systems, use dependable products, and work with installers who take pride in their craft. If you want a solar solution built to last — not one built to win the race to the bottom — Solar Fusion Solutions is the smart choice.
