How we calculate

Every number on this site comes from an hourly simulation of your roof, your usage pattern and current Victorian tariff structures — 8,760 hours a year, 25 years forward. These are engineering estimates, not quotes.

Solar yield	Melbourne north-plane monthly yields, ~1,342 kWh per kW per year; east, west and south planes weighted month by month, shifted into morning or evening
Tariff escalation	3% a year
Panel degradation	0.5% a year — the 25-year numbers already include it
Battery round-trip efficiency	90%, applied both ways; an overnight reserve is always held back
Network export limit	5 kW single-phase; the design never exceeds it
Inverter sizing	panels ÷ 1.33, rounded up to the nearest 0.5 kW
Evening window	5:30–9:30 pm; premium paid on the first 15 kWh a day. “Earned 5:30–9:30 pm” counts dispatch revenue plus the imports the window avoids
No-solar EV comparator	an 8c/kWh overnight EV plan — such plans don't require solar
Plan table	seeded Victorian plans, last verified 2026-09 — placeholders until verified

Savings depend on your actual usage, final system pricing and the plan you hold. Always compare a written quote.