Solar savings calculator
Payback years and savings from a solar install.
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How it's calculated
A solar array produces about its size in kilowatts times the peak sun hours a day, times 365, less about 20% for inverter, wiring, heat and soiling losses: an 8 kW system in 4.5 sun hours makes about 10,500 kWh a year. Each kWh is worth the retail rate under net metering, which gives the first year’s saving. Each later year is a little better as rates rise and a little worse as panels age (0.5% a year), so the savings over the period are a geometric series. The payback is the net cost after the tax credit divided by the first-year saving.
How long does solar take to pay for itself?
Typically 7–12 years in the US. The defaults here, an 8 kW system at $3 a watt with the 30% credit in average sun at 17¢, pay back in about 9.4 years, save about $61,000 of electricity over 25 years and clear about $44,000 after the system cost. Sunnier states, higher rates and state rebates bring it under 7; cloudy states with cheap power push it past 12.
Is the 30% tax credit still available?
The federal residential clean energy credit is 30% of the installed cost through 2032 for systems you buy, including with a loan, then steps down. You must owe enough federal tax to use it, though it carries forward. Leased systems and power-purchase agreements give the credit to the installer, not you.
What if my utility does not offer full net metering?
Then excess power you export is credited at less than the retail rate, sometimes a third of it, and the savings fall by whatever share of production you export, often 30–50% without a battery. Lower the electricity rate here to an effective blended figure, or size the system to your daytime use.
Results are estimates for informational purposes only and are not financial, medical or legal advice.