GuaranteeCheckWhat actually happens, in order.
Tell us your servicer & lease terms
Which servicer you're with (SunStrong, Sunrun, Renewbrook, or another), your lease or PPA type, and the numbers straight off your contract: annual guaranteed production, the true-up interval (most SunPower-era leases use 24 months), and the $/kWh true-up rate.
We pull your real production data
Enphase systems connect directly through Enphase's own login — no password shared with us. SolarEdge systems use a CSV export from your monitoring account, or manual entry if you don't have admin access (common on orphaned systems where the original installer held the account).
We tell you if you're owed money
Honest either way. The true-up formula accounts for any surplus or shortfall carried over from your last true-up period, so it's the same calculation your servicer is supposed to be running — just actually run, and shown to you plainly.
We draft your claim letter
Only if a real shortfall exists. Servicer-specific, written in your own voice, with the calculation and your production data attached as an evidence packet — you sign and send it yourself.
The exact math, with real numbers.
This mirrors the same true-up calculation GuaranteeCheck's diagnostic runs — not a simplified version of it.
If your period instead showed a surplus (actual production above the guarantee), that surplus carries forward and offsets a shortfall in a later period, rather than being paid out on its own — the same mechanic your lease's true-up clause describes. This is deliberately simple arithmetic once the real inputs exist; the hard part was never the math, it was actually running it and getting real production data instead of trusting the servicer to run it for you.
See what your own numbers show.
Free to check, no obligation. $99 only if we find real money on the table.