Ask any solar installer what happens if something goes wrong, and most will say some version of “don’t worry, it’s all under warranty.” That’s true, but it’s also doing a lot of work in one sentence. A solar PV system usually carries three or four different warranties, from three or four different companies, running for different lengths of time and covering different things. If you don’t know which one applies to which fault, you can end up chasing the wrong company, or discover too late that the thing that failed simply isn’t covered.
Here’s a straight-talking look at what’s actually protected on a typical solar and battery installation, what usually isn’t, and the questions worth asking before you sign anything.
The warranties hiding inside one solar quote
A single installation is really a stack of separate guarantees:
- Panel product warranty – covers manufacturing defects in the panel itself: faulty cells, delamination, frame failure. This comes from the panel manufacturer, not your installer.
- Panel performance warranty – a separate promise, also from the manufacturer, that output won’t drop below a set percentage of the panel’s rated power over 25-30 years. It doesn’t cover breakages, just gradual degradation.
- Inverter warranty – from the inverter manufacturer, usually shorter than the panel warranties because inverters have moving electronic parts and typically need replacing at least once across a system’s life.
- Battery warranty – from the battery manufacturer, usually expressed as both a number of years and a number of charge cycles, whichever comes first.
- Workmanship warranty – from your installer, covering the installation itself: mounting, cabling, sealing around roof penetrations, and the electrical work. This is the one people forget about, and it’s arguably the most important.
When a system underperforms, the cause is far more often a workmanship issue – a loose connection, a poorly sealed roof fixing, a shading problem nobody accounted for – than a manufacturing fault in the panel itself. That’s why who did the physical install, and what stands behind their work, matters as much as which brand of panel is on your roof.
Why the workmanship warranty is the one to scrutinise
A panel manufacturer’s warranty is only as good as the manufacturer’s ability to still be trading in twenty years, and honouring it usually still means someone has to climb on your roof to diagnose and fix the problem – which is your installer’s job, not the panel maker’s. If your installer has gone out of business, a product warranty on paper doesn’t get anyone up a ladder.
This is where an insurance-backed guarantee is worth asking about. It protects your installer’s workmanship warranty even if the company itself later closes down, by insuring the guarantee independently rather than relying on the installer still existing to honour it. Not every installer offers one, and it’s a fair question to ask directly during a quote.
It’s also worth asking who will actually turn up if a claim is needed. Some installers subcontract the physical fitting to different local tradespeople for each job, which can make it harder to trace who installed what, and slower to get someone back out. DES Renewable Energy uses our own directly employed installation teams rather than subcontractors, specifically so there’s continuity between the survey, the install and any aftercare – the people who understand your system are the people who show up if there’s ever a problem. We cover our work with our own workmanship guarantee on top of the manufacturer warranties on the panels, inverter and battery. If you’re comparing installers, our guide on how to choose a solar installer goes through the accreditation and warranty questions worth asking before you commit.
What voids or weakens a warranty
- Work carried out or modified later by someone who isn’t MCS-certified can invalidate the installation warranty and, in some cases, your eligibility for Smart Export Guarantee payments.
- Roofing, scaffolding or other trades working near the array after installation – without your solar installer being told – can damage cabling or fixings in ways that aren’t always obvious until output drops.
- Registration matters. Panel, inverter and battery warranties usually need registering with the manufacturer, sometimes within a set window after commissioning. A good installer does this for you as standard, but it’s worth confirming rather than assuming.
- Selling your house doesn’t cancel a warranty, but it does need paperwork. Most product and workmanship warranties transfer to the new owner, provided the right documents are handed over at completion – something we cover in more detail in our guide to moving house with solar panels.
How long should cover actually last?
Terms vary by manufacturer and product tier, but as a general shape: panel product and performance warranties tend to run the longest, often stretching out over 20-30 years, since panels themselves have very few moving parts to fail. Inverters and batteries typically carry shorter terms, reflecting their electronic components and, for batteries, a cycle-based lifespan rather than a simple age limit – our guide on how long solar batteries last goes into how that’s actually measured. Workmanship warranties are set by the installer rather than a manufacturer, so the length and what’s included is worth comparing directly between quotes rather than assumed to be standard.
Questions worth asking before you sign
Before accepting any solar quote, it’s reasonable to ask: who provides the workmanship warranty and for how long; whether it’s insurance-backed; who actually carries out the physical installation, employed staff or subcontractors; and whether panel, inverter and battery warranties will be registered on your behalf. None of these questions cost you anything to ask, and a reputable MCS-certified installer should be able to answer all of them without hesitation.
If you’re still working out whether your roof and usage make solar worthwhile in the first place, our free suitability checker and size estimator are a good starting point, with no pricing or sign-up required. And if you’re weighing up whether to add storage now or later, our battery storage page covers how that decision affects the rest of the system.
Talk to a local installer
DES Renewable Energy is an MCS-certified installer covering Dorset, Hampshire, Wiltshire and the surrounding counties, using our own directly employed teams from first survey through to aftercare – so if a warranty claim is ever needed, you’re dealing with the same people who installed your system. Get a free, no-obligation quote at desrenewables.com/solar-quote and we’ll talk you through exactly what’s covered before you commit to anything.