Solar panel repair, including when your installer is gone

What is solar panel repair?

Solar repair is usually electrical diagnosis rather than glass replacement. Panels themselves fail rarely; the common faults are inverter failures, dead microinverters or optimisers, corroded or unseated DC connectors, tripped rapid-shutdown devices, rodent damage to wiring under the array, and monitoring links that have quietly dropped off your Wi-Fi. Before anyone climbs on the roof, the important question is which warranty applies - panels, inverter and workmanship are three separate documents held by three different parties.

Signs you need solar panel repair

• Production has fallen against what the same system did in the same month last year, without a change in weather or shading
• Your monitoring app shows one string or one panel flat at zero while the rest of the array reports normally
• The inverter is showing a fault code, has an error light, or is silent when it should be running on a bright day
• Your electricity bills have crept back up and you have not looked at the monitoring in months
• You can see a stain, drip or damp patch on the ceiling below where the array is mounted
• There is visible damage - a cracked module, a lifted panel edge, sagging conduit, or chewed wiring and nesting material under the array
• Nuisance breaker trips on the solar circuit, or the system keeps shutting down and restarting itself

Seeing something not on this list? Browse solar problems by symptom →

How solar panel repair actually works

1. 1

   Establish the fault from monitoring before anyone is dispatched

   A good service company starts in the data. Panel-level or string-level monitoring usually localises the problem before a truck moves - one dead microinverter looks completely different from an inverter that has stopped, which looks different again from a communications dropout where the system is fine and only the reporting has failed.

   Watch forA company that will not look at your monitoring first and quotes a roof visit immediately. A meaningful share of "system down" calls are a dead router link, not a dead system.

2. 2

   Work out which warranty applies, and to whom

   You hold three separate promises: the module manufacturer covers the panels, the inverter or microinverter manufacturer covers its own hardware, and the installer covers workmanship, mounting and roof penetrations. Manufacturer warranties commonly cover the replacement part but not the labour to fit it.

   Watch forAssuming the original installer still exists. Many residential systems were sold by companies that have since ceased trading, and workmanship coverage generally does not survive them. Manufacturer warranties usually do - find your equipment serial numbers and register or claim directly.

3. 3

   Diagnosis on site: electrical first, roof second

   The technician checks inverter fault history, string voltages and currents, DC connectors and rapid-shutdown devices, then works up to the array. Loose or mismatched DC connectors and moisture ingress are common and are also a genuine fire risk, which is why this is not a job for a general handyman.

   Watch forA quote to replace panels before any electrical measurements have been taken. Panels are the most expensive and least likely thing to have failed. Ask for the readings that led to the conclusion.

4. 4

   Repair, replacement and the module-availability problem

   Inverter and microinverter swaps are routine. Panel replacement is harder, because a module from an array installed years ago is often discontinued, and a substitute has to be electrically compatible with the string it is joining rather than merely similar in appearance.

   Watch forA mismatched replacement module dropped into an existing string. On a string design, the whole string can be dragged down to the weakest member. Ask specifically how the replacement matches the existing electrical characteristics.

5. 5

   Roof leaks, re-flashing and re-commissioning

   Where the fault is water rather than electricity, the repair is roofing work: panels come off the affected area, the penetration is re-flashed properly, and the array goes back. Afterwards the system should be re-commissioned and monitoring confirmed working, not simply switched back on.

   Watch forA leak sealed with a bead of sealant over the top of the existing detail. That is a repair with an expiry date. Insist the flashing is corrected, and get the roof and the solar work documented separately in case you need to claim.

What does solar panel repair cost?

Repairs range from a low diagnostic call-out to a substantial inverter replacement. What drives the bill is labour and roof access, not parts - and whether a manufacturer warranty covers the component but leaves you paying for the fitting. Ask for the diagnostic fee and whether it is credited against the repair.

See the full solar panel repair cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →

Solar tools and calculators → Compare what your system should be producing against what it is.