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Solar Panel Servicing and Repairs in London
If your panels are generating less than they used to, your inverter is showing a fault, or nobody has looked at the system since the day it went in, we can inspect it.
Solar Panels London services, repairs and maintains solar PV systems across London and around 50 miles beyond — including systems we did not install. Our engineers are MCS certified and NAPIT registered, and most visits start the same way: we find out what the system is actually doing before we tell you what it needs.
What an annual solar service includes
Solar PV is low-maintenance, not no-maintenance. A system can lose output gradually for years without ever showing an obvious fault, and most owners only notice when a bill arrives. An annual service is how you catch that.
Generation and performance
What the system is producing measured against what it should be producing for its size, orientation and the time of year — not against last month, which will mislead you.
Panel condition
Cracking, delamination, hot spots, soiling, moss growth, and shading that has developed since the system was installed.
Inverter check
Fault and event history, firmware, operating voltages, ventilation and mounting. A unit that has been silently restarting will show up here.
Cabling and connections
DC and AC cabling, isolators, connectors and glands, checked for wear, water ingress and rodent damage.
Mounting and roof interface
Rail fixings, clamps and flashings, and any sign of movement or water tracking where the array meets the roof.
Safety, compliance and monitoring
Isolation, labelling, earthing and RCD protection — plus whether your monitoring is online, reporting correctly, and visible to you rather than only to an installer.
You get a written report of what we found, what needs attention now and what can wait. If nothing needs doing, we tell you that. We do not arrive with a list of parts to sell you.
Solar panels not generating as much as they should
This is the most common reason people call us. Low generation is a symptom, not a fault, and the causes range from trivial to serious:
- New shading — a tree or neighbouring extension that was not there at installation
- Soiling, moss or lichen, particularly on shallow-pitched arrays
- A failed or derated inverter, or one that has been silently restarting
- One string or one optimiser down, so the array is running at part capacity
- A tripped isolator or breaker that nobody noticed
- A CT clamp knocked, moved or rewired the wrong way round after other electrical work
- Simple degradation, which is real but slow — and much slower than most people assume
Two things you can safely check yourself
Whether your monitoring app is showing current data, and whether anything is shading the panels at the time of day generation should be highest.
Beyond that, please leave it alone. A solar array is a live DC source whenever there is daylight on it and it cannot be switched off at the panel. Do not open the inverter, remove covers, disconnect DC connectors or test anything live. That is a job for a qualified engineer.
Inverter faults and inverter replacement
The inverter is the part of a solar system most likely to need replacing in its lifetime — it is the component doing the most work. Panels routinely outlive their first inverter.
We diagnose inverter faults, and where a unit is beyond economic repair or the manufacturer no longer supports it, we replace it. We work with FoxESS, Sigenergy, Solis and Hanchu equipment, and we still service and replace SolarEdge systems.
Your DNO may need to be told
If the new inverter is the same size or smaller, no new application is needed, but your Distribution Network Operator should be informed of the change and the new specification. If the replacement is larger and takes the system above 3.68 kW on a single-phase supply, that needs a G99 application before the work goes ahead. We handle whichever applies — you do not need to contact them yourself. Our guide to DNOs, system size and export limits explains the thresholds in full.
It is often the moment to add storage
If the inverter is being changed anyway, moving to a hybrid inverter means battery storage can be added then or later without a second round of work. Whether that is worth doing depends on your usage and your tariff. It is a conversation, not an upsell.
When your monitoring has stopped working
A surprising number of the systems we look at are generating perfectly well and simply cannot be seen. The usual causes: the router was replaced and the inverter was never reconnected to the new Wi-Fi, the monitoring account belonged to an installer who has since closed, or the house changed hands and the login went with the previous owner.
We can get a system back online, re-register it in your name where the manufacturer allows it, and show you how to read what it is telling you.
If you are researching monitoring apps and platforms generally rather than fixing a system, our article on monitoring your solar panels through an app covers that ground.
Bird proofing and panel cleaning
Bird proofing
Pigeons nest in the gap between the panels and the roof. It is warm, sheltered and almost impossible for them to be moved on from once established. Left alone it produces mess down the roof and walls, blocked gutters, debris under the array and occasionally damaged cabling.
We fit mesh proofing around the perimeter of the array after clearing and cleaning underneath it. It is worth doing properly once rather than cheaply twice.
Solar panel cleaning
Panels are self-cleaning up to a point — rain deals with ordinary dust. What rain does not shift is bird mess, lichen, moss creeping up from the roof, and the film that builds on shallow-pitched arrays and near busy roads, which describes a lot of London.
We clean with deionised water and a pole-fed brush system, without detergents and without walking on the array. It is usually worth combining with a service visit rather than booking alone, because the access is the expensive part either way.
Commercial solar maintenance
Commercial arrays have more to lose from an unnoticed fault: a string down on a warehouse roof can run for months before anyone looks at the figures.
We maintain commercial solar across London — offices, warehouses, industrial units and hospitality. Planned maintenance visits, reactive fault call-outs, monitoring review, and inverter replacement on three-phase systems. Where a site has an export limitation or G100 arrangement, we check it is still configured and working as intended.
Systems we did not install
We are happy to take on systems fitted by someone else, and a good share of our servicing work is exactly that. It is very common for the original installer to have closed, been taken over, or simply stopped answering.
You do not need your original paperwork to book a visit, though it helps if you have it. If you have bought a house with panels already on the roof and have no idea what is up there, that is a normal starting point — working out what the system is, is part of the job.
Common questions
How often should solar panels be serviced?
Once a year is the usual interval, and that is what most manufacturer warranties expect. Systems with a battery, an older inverter, heavy tree cover or a history of bird problems are worth looking at more often.
Do you service systems installed by another company?
Yes. That is a large part of what we do, and you do not need the original installer's paperwork to book.
My generation has dropped but there is no error on the inverter. Is that normal?
It can be. Seasonal variation in the UK is large, and comparing one month to the month before will mislead you — compare the same month year on year. A genuine drop with no error showing usually points to shading, soiling, or one string or optimiser being down, none of which necessarily raise a fault.
Do solar panels actually need cleaning?
Sometimes. Rain handles normal dust on a well-pitched roof. Bird mess, lichen and moss do need removing, and shallow-pitched arrays hold dirt that steeper ones shed.
Can you replace an inverter from a brand you do not install?
Usually, yes. We diagnose first — a fault code does not always mean the unit is finished — and if it does need replacing we will explain the options rather than defaulting to the brand we stock.
Will replacing my inverter affect my Feed-in Tariff?
It can affect how the system is metered, so it needs handling properly rather than assuming. Where we replace a hybrid inverter we fit a bidirectional meter. An AC-coupled controller, which is how a battery is usually added to an existing system, does not affect the generation meter. Tell us you are on FIT when you book and we will make sure the right approach is used.
Is there anything I can check myself before calling?
Two things, both safe: whether your monitoring app is showing today's data, and whether anything is shading the panels in the middle of the day. Please do not open the inverter, remove any covers or disconnect anything — the DC side is live whenever it is light.
Do you cover my area?
We cover all of London and roughly 50 miles beyond it. If you are not sure, ask.
Book a solar system inspection
Tell us what the system is doing — or what it has stopped doing — and we will arrange a visit. If you are not sure what you have, that is fine. Working it out is part of the job.
Monday to Friday, 9am–5pm. We reply to enquiries within one working day.
Written by Marcus, Director, Solar Panels London. Last reviewed 14 September 2026. Grid connection thresholds are current at the date of review, and what any individual system needs is always subject to a site survey.
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