5 Mistakes Solar Owners Make After Installation (And How to Fix Them)

Getting solar installed feels like a milestone. The panels are up, the inverter is humming, and you've got an app on your phone showing all that lovely green energy flowing. Job done, right?

Not quite. In my experience talking to hundreds of solar owners across Australia, the installation itself is rarely the problem. It's what happens in the months and years afterwards that separates the households saving $1,500 a year from the ones wondering why their bills barely moved.

These five mistakes are incredibly common, and I've made a couple of them myself. The good news is they're all fixable, most of them without spending anything extra.

This is the big one. Your solar monitoring app shows generation: how many kilowatt-hours your panels produced today, this week, this month. And those numbers can look genuinely impressive. “15 kWh generated today” feels like you must be saving a fortune.

But generation and savings are not the same thing. If you generated 15 kWh and used 5 kWh of it directly in your home, the other 10 kWh was exported to the grid. That exported power earns you maybe 5c per kilowatt-hour. Meanwhile, you bought 12 kWh from the grid that evening at 30c per kilowatt-hour. The app says “great day!” but your meter tells a different story.

The number that actually drives your savings is your self-consumption ratio: the percentage of solar generation you use directly rather than exporting. For most Aussie households without a battery, this sits at around 20 to 40%. That means 60 to 80% of your solar is being exported at a fraction of what grid power costs.

The fix: Compare your solar app data with your actual electricity bill every quarter. Look at your import and export numbers on the bill, not just the generation total in the app. If the gap between what you're generating and what you're saving feels too wide, your self-consumption ratio is the place to start. I wrote a full breakdown of this in why your solar app doesn't match your power bill.

This is the default Australian household pattern, and it's completely understandable. You're at work all day. The kids are at school. Nobody is home to use the solar power being generated. Then everyone arrives home at 5pm and the cooking starts, the washing machine goes on, the dryer runs, the dishwasher kicks in, screens light up, and the hot water system heats.

All of that consumption happens after the sun has dropped and your panels have stopped producing. Your solar generated beautifully all day for virtually nobody, and now you're buying expensive grid power for everything that matters. It's the single biggest reason solar owners don't see the bill reductions they expected.

The evening peak period (roughly 4pm to 9pm) is also when electricity is most expensive on time-of-use tariffs, so you're not just missing your solar. You're consuming at the worst possible rates. I've covered this dynamic in detail in the evening peak trap.

The fix: Shift what you can into daylight hours. Set your washing machine on a delay start so it runs at 10am. Program your dishwasher to run after lunch. If you have a pool pump, schedule it for the middle of the day. Switch your hot water system to a daytime boost if your installer can set that up. Even small shifts make a measurable difference. For a full list of strategies, check out how to maximise solar self-consumption.

When your solar was installed, your retailer probably had you on a flat-rate tariff. A single rate per kilowatt-hour, all day, every day. Simple and predictable. And for many households, that was the right call at the time.

But once you have solar covering most of your daytime usage, the maths can change. A time-of-use tariff charges different rates depending on when you use power: cheap off-peak rates overnight, moderate shoulder rates in the morning and afternoon, and expensive peak rates in the evening. If your solar handles the daytime and you can shift some usage to off-peak periods (overnight hot water heating, for example), the cheaper off-peak rate can save you more overall than a flat rate.

That said, this is not a universal recommendation. If you use a lot of power during the evening peak and can't shift it, time-of-use could actually cost you more. It depends entirely on your household's pattern.

The fix: Log into your retailer's portal or call them and ask for a usage breakdown by time of day. Most smart meters track this. Compare what you'd pay on your current flat rate versus a time-of-use plan using your actual data. Some retailers will even run this comparison for you. Do this once a year, because your usage patterns change with the seasons.

A lot of people installed solar when feed-in tariffs were 15 to 20 cents per kilowatt-hour or even higher. The pitch was simple: export your excess solar, earn credits, and watch your bill shrink. And it worked brilliantly for years.

But feed-in tariffs have collapsed. In most states, you're now looking at 3 to 7 cents per kilowatt-hour for exports. In some cases even less. The reason is straightforward: so much rooftop solar is exporting at the same time that daytime wholesale prices have cratered. Retailers simply can't justify paying you much for power that's flooding the grid when nobody wants it.

The problem is that many solar owners are still operating as if the old feed-in rates apply. They're exporting everything and expecting the credits to do the heavy lifting. They're not. I wrote about this shift in detail in feed-in tariffs are dead, what now.

The fix: Flip your mindset from “export everything” to “use everything.” Every kilowatt-hour you use from your own panels saves you 25 to 35 cents. Every one you export earns you 5 cents. The maths is clear. If you have a battery or are considering one, a Virtual Power Plant program can also help you earn more from exports by dispatching stored energy during high-demand periods when grid prices spike. See VPP vs feed-in tariff for a comparison of the two approaches.

Batteries are the most common question I get from solar owners, and the timing is genuinely tricky. Add one too early and the payback period stretches out because you're spending $10,000 or more when your feed-in tariff was still decent and your usage patterns didn't justify it. Wait too long and you've missed state rebate windows, you've spent years exporting at rock-bottom rates, and prices may not have dropped as much as you hoped.

The sweet spot depends on your situation, but there are some clear signals. If your feed-in tariff has dropped below 5c/kWh, your evening grid usage is consistently high, and you're exporting more than 50% of your solar, the economics of a battery start to look much more favourable. State rebates can tip the balance further. Victoria, South Australia, and Queensland all have programs that reduce the upfront cost.

There's also a related question that comes up a lot: should you add more panels instead of (or alongside) a battery? If your system is undersized for your household or your roof has room, extra panels can sometimes deliver a better return than a battery, especially if your daytime usage has grown. I've covered both angles: when to add a battery to existing solar and adding panels to an existing system.

The fix: Don't wait for the “perfect” time, because it probably doesn't exist. Instead, get a quote based on your actual usage data (your retailer portal has this) and see where the payback period lands. If it's under 8 years and you plan to stay in your home, it's likely worth serious consideration. If it's over 10 years, you might benefit more from improving self-consumption first with the free strategies above.

None of these mistakes mean your solar system is a bad investment. Far from it. Solar is still one of the best financial decisions an Australian household can make. But the set-and-forget approach that worked when feed-in tariffs were high doesn't cut it any more.

The households getting the most out of their solar are the ones that check in on their usage patterns, shift a few loads into daylight hours, review their tariff annually, and make informed decisions about when to add a battery. It doesn't require constant monitoring. A quarterly check-in is enough for most people.

If you're reading this and recognising a few of these mistakes in your own setup, that's actually a good thing. It means there's room to squeeze more value out of the system you've already paid for, and that's the cheapest upgrade you'll ever make.