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Solar systems are reliable, but they are not immune to problems. Inverters fail, connections loosen, panels get damaged by hail or debris, and components wear out over time. When something goes wrong, the first question most homeowners ask is: should I repair it or replace it?
The answer depends on what has failed, how old the system is, and whether the original installer is still around to honour the warranty. For the estimated 650,000 Australian households whose installer has gone out of business, navigating repairs can feel particularly daunting.
This guide covers the most common solar faults, what repairs cost, when replacement makes more sense, and how to find a qualified repairer regardless of who installed your system.
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Common solar system faults
Inverter failure
The most common fault. String inverters have a lifespan of 5 to 12 years, and most will need replacing at least once during the life of your panels. Symptoms include error codes, flashing red lights, no output despite sunny conditions, or the inverter switching off during the day.
$1,500-$3,500 to replace
Cracked or damaged panels
Hail, falling branches, or poor handling during installation can crack panel glass or cells. Micro-cracks may not be visible but reduce output. Larger cracks allow moisture in, leading to accelerated degradation and potential electrical faults.
$300-$800 per panel
Wiring and connection issues
Loose MC4 connectors, corroded terminals, or damaged wiring can cause arc faults, reduced output, or complete system failure. These are often caused by poor installation quality or animal damage (possums and birds chewing cables).
$150-$400
Faulty isolator switches
DC isolator switches are a known weak point in Australian solar systems. They can fail due to heat exposure, water ingress, or manufacturing defects. A faulty isolator is a fire risk and should be replaced immediately.
$200-$500
Roof leak at mounting points
Poorly sealed roof penetrations can cause leaks that only become apparent during heavy rain. This is an installation quality issue and should be covered by the workmanship warranty, if the installer still exists.
$200-$600
Underperformance
Gradual output decline beyond normal degradation can indicate dirty panels, partial shading from new tree growth, a failing inverter, or connection issues. A professional inspection can pinpoint the cause.
$150-$300 diagnostic
Repair vs replace: how to decide
The repair-or-replace decision comes down to the age of your system, the cost of the fix relative to remaining value, and whether the repair will actually solve the underlying problem.
| Scenario | Recommendation |
|---|---|
| Inverter failed, panels still producing well | Replace inverter (upgrade to hybrid if planning a battery) |
| 1 to 2 panels damaged, rest of system fine | Replace damaged panels if a match can be found |
| Multiple panels damaged or underperforming | Get a full system assessment before deciding |
| System is 15+ years old with multiple issues | Consider a full system replacement for better long-term value |
| Wiring or isolator fault | Repair immediately (safety issue) |
| System undersized for current needs | Upgrade rather than repair. See our upgrading guide |
A useful rule of thumb: if the repair cost is more than 40% of the value of a new replacement component, replacement is usually the better investment. This is particularly true for inverters, where a new unit comes with a fresh warranty and modern features like battery compatibility and better monitoring.
Inverter replacement: the most common repair
Inverter failure is the number one reason homeowners call for solar repairs. String inverters typically last 5 to 12 years, which means most systems will need at least one inverter replacement during the life of the panels.
When your inverter needs replacing, treat it as an opportunity rather than just a like-for-like swap. A modern hybrid inverter costs slightly more than a basic replacement but unlocks battery compatibility, detailed monitoring, and better energy management. If you are thinking about adding a battery in the next few years, upgrading the inverter now saves you from paying for two changes later.
For a detailed breakdown of the upgrade path, see our upgrading your solar system guide.
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Finding a qualified repairer
If your original installer is still operating, start with them. They know your system, hold the workmanship warranty, and should prioritise existing customers.
If your installer has closed down, any SAA-accredited solar installer or licensed electrician with solar experience can service your system. Your panel and inverter product warranties still apply through the manufacturers, so a new repairer can lodge warranty claims on your behalf. You can check whether your installer is still trading using our collapsed solar companies tracker.
Check SAA accreditation. Only SAA-accredited installers can create STCs (which reduce the cost of new components) and are held to industry standards.
Ask for experience with your inverter brand. Familiarity with the specific brand means faster diagnosis and access to manufacturer support channels.
Get a written quote that includes diagnosis, parts, labour, and any warranty on the repair work.
Ask whether a repair or replacement is the better option. A good repairer will tell you honestly if the repair is a band-aid on a bigger problem.
Safety: what you should never do yourself
Solar systems involve high-voltage DC electricity. Even when the sun is shining and the system appears off, the panels are still generating voltage. This makes DIY electrical work on solar systems extremely dangerous and illegal in Australia without the appropriate licence.
Never touch electrical connections
All wiring, junction boxes, and inverter work must be done by a licensed electrician. DC electricity from solar panels can cause serious burns or electrocution.
Never attempt to replace panels yourself
Panel replacement involves working at heights and handling electrical connections. Both require professional skills and equipment.
Never ignore error codes
Inverter error codes and circuit breaker trips are warning signs. Some faults, particularly DC arc faults, are fire hazards. Get them checked promptly.
The only maintenance you should do yourself is cleaning panels from the ground with a hose, and visual inspections from ground level. Everything else is a job for a professional.
Frequently asked questions
How much does solar panel repair cost in Australia?
Minor repairs like replacing a faulty isolator switch or fixing loose wiring typically cost $150 to $400. Inverter replacement runs $1,500 to $3,500 for a string inverter. Replacing individual panels costs $300 to $800 per panel plus labour. A full system health check and diagnostic costs $150 to $300.
Can a single broken solar panel be replaced?
Yes, individual panels can be replaced. However, it can be tricky to find an exact match for older panels, especially if the model has been discontinued. A mismatched panel may work but can slightly reduce the output of the entire string. A qualified installer can advise on the best approach.
My solar installer has gone out of business. Who fixes my system?
Any SAA-accredited solar installer or licensed electrician with solar experience can service and repair your system, regardless of who installed it. Your panel and inverter product warranties still apply through the manufacturers. Only the installer workmanship warranty is lost when the installer closes.
How do I know if my solar panels need repair?
Signs include a noticeable drop in output on your monitoring app, error codes or warning lights on your inverter, visible damage like cracks or discolouration, circuit breaker tripping, or higher electricity bills despite no change in usage. An annual inspection can catch issues before they become costly.
Is it worth repairing an old solar system or should I replace it?
If the panels are still producing at 80% or more of their original rating and the only issue is the inverter, repair or inverter replacement is almost always more cost-effective. If multiple panels are damaged, the system is undersized for your current needs, or the technology is very outdated, a full replacement may offer better long-term value.
How long does an inverter replacement take?
A straightforward inverter swap typically takes 2 to 4 hours. If you are upgrading to a hybrid inverter or adding a battery at the same time, allow a full day. Most inverter replacements can be completed in a single visit.
The next step
If you have any questions about the information in this guide, feel free to get in touch:
Email: andy@whysolar.com.au
Tel: +61 455 221 921
If you're considering solar panels or batteries for your home, Andy and the team can help you get quotes from trusted, pre-vetted local installers:
Written by
Andy McMasterSolar Installer Partner Relations
Connects homeowners with trusted, vetted solar installers across Australia. Andy works directly with installation companies to ensure quality standards and helps homeowners navigate the quoting process.
Learn more about Andy McMaster