You spent thousands on solar panels. Your bills were supposed to drop. But they haven't — or they've crept back up. The uncomfortable truth is that many residential solar systems develop faults that go undetected for months or years, silently costing you money.
Your bill tells the story
Every electricity bill for a solar household should show two key numbers: how much power you imported from the grid, and how much you exported back to it. If your export figure is zero — or dramatically lower than it should be — something is wrong.
A typical 6.6kW system in Sydney should export at least some power on most days. If your bill shows zero exports over a full billing period, your system is likely not generating at all.
Common faults: what goes wrong
Inverter failure is the most common issue. The inverter converts DC power from your panels to AC power for your home. When it fails, your panels are still sitting on the roof but producing nothing. Most inverters have a display or LED — if it's showing an error code or is completely dark, that's your problem.
Tripped isolators are another frequent culprit. Your solar system has safety switches (isolators) that can trip during storms, power surges, or maintenance. A tripped isolator disconnects your solar — and there's no alarm to tell you.
Meter configuration issues happen more often than you'd think. After a meter change or retailer switch, the meter can lose its solar export configuration. Your system generates power, but the meter doesn't record the export. You lose the feed-in tariff payment.
What zero exports cost you per year
If your 6.6kW system generates an average of 25kWh per day and you're self-consuming 40%, that's 15kWh per day being exported. At a typical feed-in tariff of 5-8c/kWh, that's $275 to $440 per year in lost credits.
But the bigger cost is self-consumption. Without solar, you're importing all your daytime usage from the grid at 25-35c/kWh instead of using free solar power. That can add $800 to $1,500 per year to your bill.
Total cost of a broken solar system: $1,000 to $2,000 per year in lost savings. And many people don't notice for 6 to 12 months.
If you want an independent checklist of what to inspect and when to call your installer, the Clean Energy Council's solar consumer guide walks through the basics. Your bill is still the quickest place to spot a problem.
Upload your bill — we detect this automatically
When you upload your bill to BillDecoder, we check your solar export data and flag potential issues. If your exports look abnormally low for your system size and location, we'll tell you — and explain exactly what to check.