Net metering rules have splintered enough by state — and increasingly by utility within a state — that a national payback estimate is close to useless without checking your specific utility’s tariff.
The three structures worth knowing
True net metering credits exported power at the retail rate. Net billing credits it at a lower “avoided cost” rate, often 30-50% of retail. A hybrid structure credits retail rate up to your own annual usage, then avoided cost beyond it.
How to check yours
Your utility’s tariff sheet, not a national database, is the authoritative source, since rules can change mid-year following a public utility commission ruling. Search “[your utility name] net metering tariff” and look for a PDF dated within the current year.
Why this changes payback math more than panel price does
A system priced identically in two states can have a 5-year payback in one and a 9-year payback in the other, purely on export-rate differences. Get this number right before comparing installer quotes.