Enter system size, roof direction, and local rates. See payback period, 25-year savings, and IRR. All data stays in your browser.
This calculator models the 25-year cash flow of a residential solar system. It factors in the federal ITC tax credit (30% in 2026), your local electric rate, net metering or net billing policy, and panel degradation (0.5% per year).
Enter your system size, total cost, expected annual production, and rate. The calculator shows payback period, internal rate of return (IRR), and cumulative savings over 25 years.
Tip: Net metering gives you 1:1 credits. Net billing pays wholesale (3-5¢/kWh) for exports. If your utility switched to net billing, add a battery to store excess solar instead of selling it cheap.
See if time-of-use helps your solar.
Check your current costs.
Efficiency first, then solar.