Solar math, done right
How much will solar actually save you?
PanelMath calculates real solar payback, system size, and 25-year savings using your zip code, your utility's actual rate plan, and NREL sun data — not generic averages. Free, no signup, no installer call required.
Real utility rates
Pulled from EIA Form 861 and OpenEI — your exact rate plan.
Local sun data
NREL PVWatts irradiance for your specific zip code.
Honest payback
Net metering, incentives, and degradation factored in.
First wave: California, Texas, Florida, Arizona, New York. More cities each week.