Households often assume the rebate is only for new solar. It is not. The discount attaches to the battery, and the solar behind it can be any age.
Does the solar system need to be a certain age?
No. The program says the battery must connect to a new or existing solar system. It does not say the solar had to be installed after a certain date, and it does not say it had to be installed before one. A system from 2012 qualifies on the same terms as one installed last month.
Can I claim if my solar was installed years ago?
Yes, and for the same reason. The age of the panels is not a test. What the installer must show is that the battery is installed with an eligible solar system at the same property. If you have received solar STCs or a feed-in arrangement on the old system, that does not affect the battery discount. The battery creates its own certificates.
What actually matters with older solar
Eligibility is mostly about the battery and the install. Practical points for an older system:
- Inverter compatibility. An AC-coupled battery works with almost any older solar inverter. A DC-coupled battery needs a hybrid inverter, so an older string inverter may have to be replaced. Replacing it may count as a new solar installation with its own rules.
- System condition. If the panels, isolators or wiring fail inspection, the installer will need to fix them before commissioning.
- Approvals. Your network (DNSP) may need a new connection application when you add storage.
- The battery itself. It must be CEC-approved, VPP-capable and installed by an accredited installer. See which batteries are eligible.
- Commissioning date. The battery must be commissioned on or after 1 July 2025. A battery you already have at home is not covered; see batteries installed before 1 July 2025.
What this means for installers
For retrofit jobs, photograph the existing inverter label and the new battery serial, and record both in the job. The current evidence rules (in force since 1 March 2026) are laid out in the battery submission guide and the battery photo guide for 2026. Older solar makes for the same claim as new solar, with one extra thing to check, which is that the inverter and battery are compatible.
What this means for you
Because the factor steps down every six months (6.8 at the time of writing, then 5.7 on 1 January 2027), there is a cost to waiting even when your solar is old. Run your size through the battery STC calculator and compare. The battery STCs pillar covers the full rules, and /pricing/ shows how installers are paid for certificates.