Solar Panel Payback
Will rooftop solar pay for itself, and when? Enter a system size and your power rate, and we set the sun-hours from your region to estimate the yearly output, the dollars saved, and the years to break even.
Set your place to estimate your local sun.
How payback is figured
A solar array's yearly output is its size in kilowatts times the peak sun hours your location averages each day, times 365, times a performance ratio of about 0.84 for real-world losses, the model the U.S. National Renewable Energy Laboratory uses. Multiply that output by your power rate for the yearly saving, divide the install cost by that saving, and you have the simple payback in years. It ignores rebates, financing, rate inflation, and panel aging, all of which move the real answer, so treat it as the first cut, not the contract.
Output model from NREL PVWatts; cost benchmark ($2.50 to $3.30 per watt) from NREL/DOE. Sun-hours are regional averages; your roof's pitch, shade, and direction change them. Not financial advice.