Quick answer
Solar payback is driven by installed cost, annual generation, self-consumption, retail tariffs and export value. It should be treated as a range, not a guaranteed year.
What matters most
- Higher self-consumption generally improves value when import prices exceed feed-in tariffs.
- Financing and maintenance can extend economic payback.
- Test conservative and optimistic scenarios.
Solar decision framework
Separate production from value. System size and location drive generation; your daytime load drives self-consumption; tariff structure determines what each kilowatt-hour is worth.
How to calculate it with SunnyWatly
Use the relevant calculator with your own bill, quote or vehicle information. Defaults are examples only and can become stale as tariffs, rebates and hardware change.
Do not rely on a headline figure alone. Ask what assumptions sit behind the estimate and whether they match your property, tariff and usage pattern.
What can change the result
- Electricity usage and time of day.
- Retail import and feed-in tariffs.
- Roof, shading, inverter or charger constraints.
- Hardware efficiency and usable capacity.
- Network limits and future tariff changes.
Primary public sources used by SunnyWatly