A solar panel warranty is really two separate promises, and the impressive number on the sales brochure is usually the weaker one. Every mainstream panel sold in the UK carries a product warranty covering physical defects, commonly 12 to 15 years though the full spread runs from 10 to 25, and a performance warranty guaranteeing a minimum power output, typically 25 to 30 years. What each one actually pays for is narrower than most owners assume. I have read the current warranty documents for the panels listed in my panel directory, and this guide covers what they genuinely promise, what they exclude, and how a claim works in practice.
Why does every panel have two warranties?
The product warranty covers the panel as an object: defects in materials and workmanship that stop it working. The performance warranty covers the panel as a generator: a guaranteed floor under its power output as it ages. They run on different clocks and pay out under different conditions.
Product warranties on current panels commonly run 12 to 15 years, with some budget lines at 10 and some premium dual-glass lines at 20 or 25. Performance warranties are longer but softer: they define an allowed degradation curve, not a promise of your roof’s actual yield. A typical modern N-type warranty allows around 1 percent loss in year one and 0.4 percent a year after that, arriving at a floor near 87 percent of nameplate at year 30. LONGi’s Hi-MO X10 distributed-generation warranty document, in the regional versions I could check, allows just 0.35 percent a year for a floor of 88.85 percent, while older mainstream curves bottom out at 84.8 percent after 25 years. The panel comparison table in my directory lists both warranty periods for every model, and the spread between brands is wider than the headline wattages suggest.
Note what the performance warranty is not: it is not a guarantee that your system will generate any particular number of kilowatt hours. Weather, shading and soiling sit outside it entirely. It promises only that the panel itself, measured under laboratory conditions, can still deliver its floor percentage.
What do the exclusions actually say?
The exclusion lists are where warranties are won and lost, and they follow the same pattern across every manufacturer I have read: anything traceable to installation defects, extreme or corrosive environments, external events, or modification is your problem, not theirs.
- Installation not following the manual. Every document excludes damage from improper installation, and several exclude work by unqualified installers outright. A DIY installation does not automatically void the warranty, but any defect the manufacturer can attribute to the install will be rejected, so following the installation manual to the letter and photographing the work matters.
- Moved panels. Warranties generally survive a house sale only if the panels stay put. Remove them to another roof and most documents end the cover, which is worth knowing before reusing panels from another system.
- Serial numbers. A tampered, removed or unreadable serial label is grounds for outright rejection. Keep a photo of every serial number from installation day.
- External events. Storm, flood, lightning, power surges and glass broken by impact are excluded. Those are insurance-shaped risks rather than manufacturing defects, and whether your buildings policy actually covers the panels is worth confirming rather than assuming.
- Appearance. Discolouration and cosmetic change that does not affect output is explicitly not a defect.
Who pays for removal, labour and scaffolding?
You do. This is the single biggest surprise in the small print: a successful warranty claim gets you a repaired or replacement panel, and almost never pays for taking the old one off the roof or putting the new one up.
The wording is consistent across the warranty documents I have read. Aiko’s, for example, states that all costs incurred in removing, repackaging, installing or reinstalling products are borne by the customer, and the residential documents follow the same pattern as the utility-scale ones. JA Solar and LONGi carry near-identical clauses, and Trina shifts even freight and materials to the buyer once the product-warranty years have passed and only the performance promise remains. The manufacturer also chooses the remedy at its sole discretion: repair, replacement, or a refund of the panel’s depreciated residual value, which after 15 years is a modest sum.
For a roof-mounted panel the practical consequence is stark. The free replacement panel might be worth less than the scaffolding and labour needed to fit it. This is why a warranty claim for a single panel on an ageing system is often not worth mobilising, and why the warranty matters most in the early years, when a batch defect can take out multiple panels and the labour is worth mobilising once.
How do you actually claim on the performance warranty?
Not with a screenshot of your monitoring app. Performance warranties are settled by laboratory measurement under standard test conditions, and the burden of proof sits with you.
The documents typically require notice within about 30 days of spotting the problem, with serial numbers, purchase evidence and supporting data. The panel’s output is then measured at standard test conditions by a laboratory the manufacturer accepts, and several manufacturers require the customer to pay the testing fee up front, reimbursed only if the claim succeeds. Your monitoring showing a bad month proves nothing contractually, since weather, soiling or a system fault could explain it. If your generation has dropped, work through my low output diagnostic guide first, because the cause is far more often elsewhere in the system than inside a panel.
What happens when the installer or manufacturer disappears?
The panel warranty is a contract with the manufacturer, usually a Chinese parent company, so it survives your installer going bust. Whether you can practically exercise it alone is another matter, and if the manufacturer itself fails, the warranty generally dies with it.
When an installer folds, three layers matter. The manufacturer product and performance warranties remain claimable directly, though you lose the intermediary who knew the claims process. The installer’s workmanship guarantee, which RECC and MCS rules require to run at least two years and be transferable, should be backed by an insurance-backed guarantee that honours it if the firm ceases trading; these policies typically cap out around ten years and cover workmanship faults only, not panel performance. And underneath both sits consumer law, covered below. Manufacturer failure is rarer but real: GivEnergy Ltd entered administration in April 2026 and its administrator has stated the company will not honour further hardware warranty claims, which is the scenario no paperwork fully protects against. Spreading risk toward manufacturers with long track records and standard, widely serviceable hardware is the honest mitigation.
How do your consumer rights sit under all this?
The Consumer Rights Act 2015 gives you rights against the business that sold you the goods, and no warranty can take them away. Goods must be of satisfactory quality, which the Act says includes durability, and a panel that fails early may breach that term regardless of what the warranty allows.
The claim runs against the seller, which for most installations means the installer who supplied the kit, and it can be brought up to six years after purchase in England and Wales, five in Scotland (gov.uk guidance). Within the first six months a fault is presumed to have existed at sale unless the trader proves otherwise; after that the burden flips to you. These rights and the manufacturer warranty run in parallel, and government guidance is explicit that a trader may still have to repair or replace goods after the written guarantee has expired. The catch is the obvious one: rights against a seller are only as good as the seller’s continued existence, which brings us back to insurance-backed guarantees.
Are inverter warranties different?
Yes, and usually shorter, which is the right way round, because the inverter is the component most likely to fail. Panel warranties measure decades; inverter warranties measure years, with paid extensions doing the heavy lifting.
Solis grid-tied and hybrid inverters carry five years as standard in the UK, extendable to 10, 15 or 20 by paid application within 12 months of the warranty starting, a deadline that quietly expires while most owners are still enjoying the novelty of their monitoring app. SolarEdge inverters carry 12 years with extensions available, and its power optimisers 25. Registration deadlines matter in two different ways: for brands like Solis the paid extension window closes for good, while some manufacturers tie their full advertised term to activating or registering the system, so an unregistered install can sit on a shorter default. Check which pattern your brand uses. Like the panel documents, inverter warranties exclude labour, access and transport, so even a covered failure carries a real cost to resolve. Current models and terms are in my inverter directory, and what a replacement actually involves is in my repairs guide.
The practical summary fits in one paragraph. On installation day, collect the serial-matched warranty PDF for your exact panel model, the inverter warranty terms and any registration confirmations, your invoices, the MCS certificate and the insurance-backed guarantee certificate, and keep photos of every serial number. Register anything that needs registering before the deadlines. That folder, which my solar documents guide covers in full, is worth more than the headline warranty years, because a warranty you cannot evidence is a warranty you do not have.
