Solar guide
Replacing or upgrading an old solar system
Many homes have had solar for over a decade. When an older system fails or no longer covers your needs, there are a few ways forward, and they're treated differently by the federal discount and the 44c tariff.
Your options
Replace the inverter
The usual fix when the inverter fails. A like-for-like or smaller inverter keeps the 44c tariff in Queensland. A battery-ready (hybrid) inverter is worth asking about if you're planning a battery.
Add panels
Possible if the existing inverter has spare capacity and both the new panels and the inverter are on the approved lists. The added panels can earn the federal discount.
Replace the whole system
All-new panels and inverter, sized for how you use power now. A complete new system can earn the federal discount if every component is new and approved.
Add a battery
If the system works but you export most of what it makes, a battery may suit better than more panels.
Learn more
The federal solar discount (STCs) for upgrades
Small-scale technology certificates reduce the price of eligible systems. For older systems, the Clean Energy Regulator's guidance is:
- Replacing the whole system: eligible, if all the panels and the inverter are new, haven't been used for a previous claim, and are on the approved list.
- Replacing some panels in an existing system: not eligible.
- Adding panels to an existing system: eligible, if the new panels and the existing inverter are approved and the inverter has enough capacity.
On Queensland's 44c Solar Bonus Scheme?
The 44c feed-in tariff ends on 1 July 2028. Until then, replacing the inverter with one of the same size or smaller keeps it, as does replacing other parts like for like. You can add panels up to the size of your inverter.
A larger inverter, or panels beyond the inverter's capacity, ends eligibility. Weigh up what the tariff is still worth to you before 2028 against what a bigger system would deliver.
Approvals
- In South East Queensland, Energex must approve solar systems before they're installed. Ask the installer to confirm the application is included.
- New and replacement systems of 10 kVA or more in Queensland need an emergency backstop device. Check it's in the quote if your new system is that size.
Ask each installer
- Is it the inverter, the panels or the wiring that's at fault, and how did you test it?
- What would replacing just the inverter cost, compared with a new system?
- Does your quote earn STCs, and how many?
- If I'm on the 44c tariff, will I keep it with this work?
- What happens to the old panels and inverter?
Sources
Facts on this page were checked on 15 October 2026. Rules and programs change, so confirm details with your installer.
Frequently asked questions
Should I replace just the inverter or the whole system?
If the panels are working and the system still suits your needs, a new inverter is often enough. If you need much more power, or the panels are failing too, compare it with the cost of a new system, which can earn the federal discount.
Can I get the solar discount on replacement panels?
Not for replacing some panels in an existing system. A complete new system, or extra panels added to an existing system with spare inverter capacity, can be eligible.
Will upgrading my system end my 44c feed-in tariff?
It can. A larger inverter, or panels beyond the inverter's capacity, ends eligibility. Like-for-like repairs and replacements keep it.
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