How much solar can your specific roof produce?
Regional rules of thumb only get you so far — the sunshine at your address can differ meaningfully from a neighbor two states away, and even from county to county. This estimator removes the guesswork by geocoding your address and querying the National Renewable Energy Laboratory’s PVWatts model, the same tool professional installers rely on, for production data tied to your exact latitude and longitude.
What the numbers mean
We return three figures that anchor every other solar calculation. Peak sun hours describe how much full-strength sunlight your location averages per day. The production ratio tells you how many kilowatt-hours a single kilowatt of panels will generate at your home over a year, after standard system losses. And annual production scales that ratio to the system size you enter, giving you a concrete kilowatt-hour total to compare against your usage.
Why the monthly curve matters
Solar output isn’t flat across the year. Longer days and a higher sun angle make summer production far exceed winter, and the monthly chart makes that seasonality visible. This helps you set expectations: a system sized to cover your annual usage will bank surplus credits in summer that offset shorter, cloudier winter days — provided your utility’s net metering allows it. If it doesn’t, the winter dip is a strong argument for a battery.
From estimate to plan
The production ratio this tool returns is the key input for the rest of your planning. Drop it into the System Size Calculator to right-size your array, then into the Solar Savings and Payback calculators to translate sunshine into dollars. Because every result here lives at a shareable URL, you can bookmark your address’s estimate and return to it as you gather installer quotes. Remember that PVWatts models a typical weather year and a standard roof orientation, so treat the output as an excellent planning estimate to be confirmed by a professional shade and roof analysis.