How to Understand Your Results
Self-consumption is what actually drives your savings. Solar saves you the most when you use the power as it's generated, since that offsets electricity you'd otherwise buy at the full retail rate. Power your household doesn't use gets exported to the grid, and is credited back at your feed-in tariff — usually a fraction of the retail rate, which is why matching system size to your actual usage matters more than just going as big as possible.
- Payback Period: The time for your cumulative savings to equal your installation cost. A payback of roughly 3–7 years is common for well-matched systems in Australia — the better your usage lines up with generation hours, the faster it pays off.
- Why "Net" Cost? Always input the final cost of your system after any government rebates (like STCs) have been deducted, not the sticker price.
- Maintenance: Solar is low-maintenance, but panels may need professional cleaning every 2–3 years to maintain peak efficiency.
Frequently Asked Questions
A payback of roughly 3–7 years is common for well-matched systems in Australia, though it depends heavily on your usage patterns, system size, and local feed-in tariff. Enter your own figures above for an estimate specific to your situation, rather than relying on a generic industry average.
It depends mainly on how much of your generated power you use directly versus export, since self-use offsets electricity at the full retail rate while exported power is only credited at your feed-in tariff. Enter your electricity price, feed-in tariff, and daily usage above to see an estimate based on your own numbers.
This calculator applies a realistic performance derating (accounting for inverter losses, panel temperature and dust) and models self-consumption based on your actual household usage rather than assuming all generated power is used at full retail value. Brochure figures sometimes assume ideal, loss-free conditions.
It compares your daily solar generation to your average daily usage, then applies a coincidence factor to account for the fact that even on high-usage days, not all of that usage happens during sunlight hours. Power beyond what you're likely to use directly is treated as exported to the grid at your feed-in tariff rate.
Yes, significantly. A battery lets you store midday solar generation and use it in the evening instead of exporting it at the lower feed-in rate, which typically increases self-consumption and annual savings. This calculator does not currently model battery storage.
Not necessarily. A system much larger than your household's usage will export a larger share of its output at the lower feed-in tariff, which can extend your payback period compared to a system sized closer to your actual consumption.