Inverter replacement, the normal event
Panels carry long performance warranties. Inverters carry considerably shorter ones, and they contain the components most exposed to heat cycling.
So a system reaching its early teens with an inverter fault is behaving as expected, not failing prematurely. The replacement is a day of work, and the array continues.
Two practical questions: is the original model still available, and if not does the replacement match the array’s string configuration and voltage. Where it does not, some rewiring is involved. Our inverter replacement planner sets out what to check.
Adding a battery to existing solar
Retrofitting storage is common and the method depends on what you already have.
- AC coupling. The battery brings its own inverter and sits alongside your existing system. Works with almost anything, costs one extra conversion in efficiency.
- Replacing with a hybrid inverter. One unit handles solar and storage. More efficient and tidier, and it makes obvious sense when the existing inverter is due for replacement anyway.
- The timing argument. Doing both at once shares the permit, the mobilisation and much of the electrical work. Doing them two years apart does not.
Upgrade or replace the whole system?
Replacing an entire working array is rarely justified. Panels degrade slowly and predictably, and a fifteen-year-old module producing at 85% of its original rating is doing its job.
The cases where full replacement genuinely makes sense are narrow: widespread panel failure rather than a few modules, a roof being replaced anyway so the array is coming off regardless, or a system so undersized for changed circumstances that redesigning beats extending.
Otherwise, targeted upgrades are almost always better value.
Check the tariff before you book
Like adding panels, some upgrades count as modifying the system, and in certain jurisdictions that can end grandfathered export terms.
A like-for-like inverter replacement usually does not. Adding storage or capacity is more likely to. Ask your utility in writing which category your planned work falls into before you commit — it costs nothing and occasionally changes the plan.
How the work runs
- Diagnose properlyConfirm what has actually failed. An inverter fault code is a symptom, not always the cause.
- Check warranty positionProduct, workmanship and inverter warranties may each apply, and each may be held by a different company.
- Confirm the tariff impactIn writing from the utility, before the work is booked.
- Decide the scopeLike-for-like replacement, or hybrid inverter and battery while the system is open.
- Specify the replacementMatched to the array’s string configuration and voltage, not just to the old nameplate.
- Permit where requiredLike-for-like swaps sometimes need only notification; adding storage generally needs a full permit.
- Install and verifyCompare post-work output against pre-fault production. Do not accept "it is running" without numbers.
What moves the price
We do not publish a national average and present it as your price. These are the variables that separate two quotes for the same job — run your own numbers with the cost guides and calculators, and check what incentives you actually qualify for.
| Factor | Why it moves the number |
|---|---|
| What is being replaced | A string inverter is one unit. Replacing failed microinverters means roof access per module. |
| Hybrid upgrade vs like-for-like | A hybrid costs more up front and saves the cost of a separate battery inverter later. |
| Battery added at the same time | The battery itself, plus the backup subpanel if you want outage protection. |
| Warranty coverage | An in-warranty part may be free while the labour to fit it is not. |
| Equipment obsolescence | Older systems may have no direct replacement, turning a swap into a partial redesign. |
| Permitting | Storage generally triggers a fuller permit and inspection than a straight swap. |
What to ask before you commit
Take this list to the conversation. A professional who answers these directly is telling you a lot; one who deflects is telling you more.
- What exactly failed, and what is the evidence?
- Is any of this covered by warranty, and who pays the labour if the part is free?
- Does the replacement match my array’s string configuration, or does it need rewiring?
- Does this work change my export terms? Have you confirmed that with the utility?
- If I am replacing the inverter anyway, what does a hybrid plus battery cost instead?
- Will you show me production before and after?
Common questions
How often do solar inverters need replacing?
Inverters carry materially shorter warranties than panels and are the component most likely to need attention during a system’s life. A fault in the early teens of a system’s life is normal rather than premature.
Can I add a battery to solar I already have?
Yes. Either AC-couple a battery with its own inverter alongside the existing system, or replace the existing inverter with a hybrid that handles both. The second makes particular sense if the inverter is due for replacement anyway.
Should I replace my whole solar system?
Rarely. Panels degrade slowly, and a fifteen-year-old module at 85% of its rating is working as designed. Full replacement makes sense mainly when panels are failing widely, or the roof is being redone and the array is coming off regardless.
Will upgrading affect my net metering?
It can. A like-for-like inverter swap usually does not, while adding storage or capacity is more likely to count as a modification. Confirm with your utility in writing before booking the work.