What Happens to the Warranty and Output When You Buy Used Solar Panels?
Summary
The manufacturer's warranty goes away. SanTan Solar, a used-panel seller, states plainly that "used panels do not carry a manufacturer's warranty" and offers its own one-year warranty instead, with an extended five-year option on request. Output will already be lower: applying the 0.5% per year median from an NLR review of nearly 2,000 degradation rates, a 300 W panel used for 10 years would be around 285 W.
Where the panels come from
SanTan's FAQ says its used panels come from solar farms and other large commercial sites and are typically 5 to 10 years old. The company sells new, used, refurbished, repaired, and overstock panels, and says each used panel is visually inspected and tested before sale.
EPA's position on panels like these is that a used panel sent to a reseller for legitimate reuse as a panel that generates electricity is not a solid waste. Anyone handling panels for reuse is expected to keep records showing that they were reused.
Living with a one-year warranty
Bought new, an REC Alpha Pure-RX carries a 20-year product warranty (25 with a certified installer) and 25 years on performance, and a Qcells Q.TRON BLK M-G2+ carries 25 years on both. Buy used, and only the seller's warranty is left. SanTan's terms give a one-year replacement or repair warranty on equipment it sells.
For output, a 2013 review by NLR researchers Jordan and Kurtz collected nearly 2,000 degradation rates from 40 years of field testing and found a median of 0.5% per year.
| Years in service | 300 W panel at 0.5% per year |
|---|---|
| 5 | about 292.5 W |
| 10 | about 285 W |
| 15 | about 277.5 W |
Those figures use the median, and any single panel can land above or below them. A separate NLR article puts typical degradation at "generally 0.5%–1%" a year; at 1%, the same panel would be down to 270 W after 10 years.
Sources
- SanTan Solar — Frequently Asked Questions
- REC Group — REC Alpha Pure-RX
- Qcells — Q.TRON BLK M-G2+ series datasheet (Rev02, 2026-04)
- SanTan Solar — Terms and Conditions
- U.S. EPA — Solar Panel Frequent Questions (updated 2026-09-18)
- NLR — Photovoltaic Degradation Rates: An Analytical Review (Jordan and Kurtz, 2013)
- NLR — Aging Gracefully: How NREL Is Extending the Lifetime of Solar Modules
We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.