About Solar Savings Calculator
A free, independent tool that helps households in the United States and Australia work out whether rooftop solar is worth it — before they spend a cent.
Why we built it
Solar quotes are confusing, and installers have an obvious incentive to make the numbers look great. We built this calculator to give you a neutral, transparent estimate you can run yourself, as many times as you like, with your own numbers.
Every input is explained and every assumption is shown, so you can see exactly how your payback period and long-term savings are derived.
How our numbers work
- Generation — system size (kW) × your state's daily solar irradiance × 365 days × a performance ratio for real-world losses.
- Savings — the power you use on-site offsets your retail electricity rate; surplus power earns your state's feed-in tariff.
- Degradation — panels produce slightly less each year (about 0.5%/yr standard, 0.4%/yr premium).
- Price rises — we escalate electricity prices each year, so future savings grow realistically.
- Incentives — US results apply the 30% federal residential solar tax credit; Australian per-watt prices already reflect the STC rebate.
Our data sources
Figures are representative 2026 estimates compiled from publicly available sources:
- Solar irradiance — national renewable-energy and meteorological datasets by state.
- Electricity rates & feed-in tariffs — regulator and utility published residential averages.
- Install costs — published per-watt market ranges (US $2.50–$3.50/W, AU $1.50–$2.50/W).
These are estimates for guidance only. For a binding figure, always request at least three quotes from accredited installers.