Cheap used panels are tempting, and online listings often promise that the buyer can still claim the rebate. In practice, the STC scheme is built to reward new, approved equipment, and used panels fall outside it.
What the rules say
For solar PV, panels and inverters must be on the Clean Energy Council approved list. The CER also treats the components in a system as a claim on a specific installation. If the panels have previously received STCs, the CER’s guidance is that replacing them does not entitle the system to additional STCs. A used panel moved from another roof has typically either earned certificates already or been installed in service. That puts it outside the scheme.
Refurbished panels
A refurbished panel is a used panel that has been tested or repaired. It is not a new product, and a refurbished model does not become eligible by being re-sold. If the model is no longer on the approved list at the time of installation, it fails on that ground as well. See what happens if panels are not on the CEC list.
Can I claim STCs on second-hand panels
If you install second-hand panels and want certificates, the answer is no in the ordinary case. That means no STC discount in the quote, and the customer should understand that the saving from cheap panels is partly offset by the missing rebate. As an example, a 6.6 kW system in zone 3 in 2026 would earn 45 STCs, or roughly $1,700 to $1,800 at the roughly $38 to $40 spot range at the time of writing. A second-hand price has to be lower than that to break even.
Mixing used and new panels
Adding new approved panels to an old array can be eligible as an extension for the new capacity, but the old panels do not earn anything again. See adding panels to an existing system.
What this means for installers
Do not offer an STC discount against used or refurbished panels. If a customer insists on them, make the lack of certificates explicit in the quote. A claim that includes ineligible components risks rejection, and under the scheme the CER can reverse certificates; see how STC audits work.
For the broader rules, see which systems are eligible and the STC trading overview. Rates are on the pricing page.