The first check on solar panels after a storm, hail or a lightning strike nearby is a visual one from the ground, never from the roof. Cracked glass, a panel that looks tilted against the row next to it, or fittings hanging loose are worth photographing for an insurance claim. The damage that actually decides whether you lost production, though, is usually the kind nobody can see: a string or an optimiser that stopped while the rest of the array, and the app, carry on as normal. Your own daily production figures, set against the days before the event and against what the weather allowed, are what settle it.
What to check from the ground — and what to leave alone
The Health and Safety Executive’s guidance is blunt: avoid work at height where you reasonably can, and do as much as possible from the ground. It warns against resting a ladder on weak surfaces such as glazing or plastic gutters, and counts falls from height among the biggest causes of workplace deaths and major injuries. Leave a hail-damaged roof to someone whose job this is.
From the garden, an upstairs window, or with binoculars, you are looking for obvious physical damage: broken or missing glass, a panel sitting at a different angle from its neighbours, or cable clips and fittings that look loose or displaced. Leave anything closer to a professional. Enphase advises the same, “for your safety and to abide by system warranties”: climbing up yourself can affect your warranty cover.
If you can see damage, photograph it from where you are standing before anything gets tidied away or repaired. The insurance section below explains why that record matters.
Solar panel storm damage: what you can see, and what you can’t
Some storm and hail damage announces itself. Enphase’s advice after severe weather states plainly that “massive stones can cause microcracks and even shatter panel glass”. Shattered or cracked glass is the visible end of an event that can also crack a cell without breaking anything you would notice looking up.
A microcrack, a failed optimiser, or a string that has stopped is not visible at all, and none of them necessarily stop the rest of the system from working. Enphase fits a microinverter to each panel; SolarEdge and Growatt systems are covered on their own monitoring pages. A single failed link can sit inside a system that otherwise looks and behaves normally, which is why Enphase frames panel-by-panel monitoring as something that “makes it easier to detect losses.” Without that resolution, a loss confined to one part of the array is easy to miss inside a total that still looks broadly sensible.
Solar panel hail damage: what the panel standard actually tests for
In Great Britain, hail is most common in the west and in winter. The most damaging hailstorms are relatively infrequent and usually come in summer. Hailstones range from 5mm to over 50mm across, and most are smaller than 25mm, according to the Met Office.
Solar panels are generally certified to the international module standard IEC 61215. To pass its hail test, a panel must come through 11 strikes from a 25 mm (1 inch) ice ball at 51 mph visually undamaged and with less than 5% power loss, as the US Department of Energy describes it.
That is a specific, repeatable test at a stated ball size and speed, not a promise that a panel is hail-proof. The 25mm test ball sits close to the top of what the Met Office describes as a typical UK hailstone; the larger stones it also records, over 50mm, are outside what the certification test covers.
Solar panel lightning damage and surge protection
UK thunderstorms are most common over the East Midlands and the south-east, according to the Met Office, so how much this applies to you depends partly on where you live.
Surge protection for a grid-connected solar installation in the UK is governed by the wiring regulation BS 7671 (the UK’s national wiring standard). An MCS-certified installer can confirm what surge protection your system already has fitted, and whether it meets the current edition of the regulation. Ask after any strike nearby, not only a direct one on the array.
Storm and hail damage: what a home insurance claim needs — and why the date matters
Which?’s advice for a claim after a storm: contact your insurer as soon as possible, photograph everything you can, and if you pay for an interim fix yourself, tell your insurer and keep the receipts.
Which? found 27 potentially unfair storm definitions in home insurance, each excluding damage by at least one of rain, snow or hail alone, without strong wind. Hail damage on a still day can fall outside what a policy counts as storm damage at all. What counted as the storm, and exactly when it happened, can decide whether a claim is paid.
This is where your own figures belong, alongside the photographs. If your daily output changed sharply on a specific, nameable day, you have a date to set against the weather on that day, rather than an impression that output has seemed a bit low lately.
Why the app can still look normal
After the event, the installation usually looks fine from the ground, and the monitoring app usually looks fine too. An inverter that lost communication and restarted reports current power quite happily, because that figure only describes what is coming through the parts of the system that are still working. A string, an optimiser or a microinverter that stayed dark after the event does not turn into a warning on a screen that is, correctly, reporting everything else as normal.
You cannot see that from the roof, or from a green light on the inverter. The only figure that shows it is the daily total, set against the days immediately before the event, and against what the weather actually allowed on each of those days. That is ordinary arithmetic, the same kind you would use to sanity-check any other bill.
Read it from your own figures
The manufacturer app or a monthly report gives you daily kWh going back as far as your account has been logging. Pull up the days after the event and the days immediately before it, and line them up against what the weather was actually doing each day: a bright, cold day should produce more than a grey one, whatever else is going on. The full method for comparing your own production against the weather works the same way here as it does for any other unexplained dip, pointed at a specific date. If El Niño is in the headlines and what you are looking at is a whole winter of low numbers rather than one bad day, what a seasonal forecast can and cannot say about your December output is the same weather-or-fault question stretched across a season.
If the days after the event track the weather the way the days before it did, the event did not cost you anything worth chasing. If one day’s total looks wrong for how much sun there was, that is your date: the one for an insurance claim, and the one to give an installer or a manufacturer’s support line if a warranty repair is what you need.
Solmiro makes that comparison every day: it works out what the weather over your roof allowed, and it e-mails you when production falls well short of that or stops. Connecting is free.
If the figures still don’t add up
A day that stays at zero, or a total that never recovers to where the weather says it should be, is not a monitoring question any more. At that point a stopped string, optimiser or inverter is what you are chasing down directly, ideally with the exact date your own figures identified already in hand.
Questions owners ask
Do I need to get onto the roof to check for storm or hail damage?
No. The Health and Safety Executive's general guidance is to avoid work at height where reasonably practicable and to do as much as possible from the ground. A closer look is a job for a professional — partly for safety, and partly because climbing up yourself can affect your system's warranty, per manufacturer guidance.
What size of hail are solar panels tested to survive?
The international module standard, IEC 61215, requires a panel to come through 11 strikes from a 25mm (1 inch) ice ball at 51 mph visually undamaged and with less than 5% power loss to be certified. That's a specific pass bar, not a guarantee against every hailstone — the Met Office records UK hail over 50mm.
Why does my solar monitoring app still look normal after a storm?
Because the figures it shows describe what's coming through the parts of the system that are still working. A single string, optimiser or microinverter can stay dark after an event while the rest of the array, and the app, keep reporting as normal — only your daily total, checked against the weather, shows the gap.
What do I need for a home insurance claim on storm or hail damage to solar panels?
Which? recommends contacting your insurer as soon as possible, photographing the damage, and keeping receipts for any interim repairs. Its own research found that some storm-damage definitions exclude hail, rain or snow alone, without strong wind alongside it — which is why pinning down exactly what happened, and when, matters for a claim.
Do UK solar panels need extra protection against lightning damage?
Surge protection for a grid-connected solar installation falls under the wiring regulation BS 7671. An MCS-certified installer can confirm what your system already has fitted and whether it meets the current edition.