Solar panel warranties explained: what's actually covered in the UK?

A typical UK solar installation carries four or five separate warranties, each from a different party: 10–15 years on the panels as a product and 25–30 years on their performance from the panel maker, 5–10 years on the inverter as standard, around 10 years or a cycle limit on a battery, 10–20 years on the mounting, and anywhere between 1 and 10 years on the work itself from the installer. That last one, the workmanship warranty, is the one most likely to matter, because roof leaks, loose fixings and wiring faults show up far more often than a failed panel. It is also only as good as the company that issued it, unless it is insurance-backed.

This guide is about the paperwork, not the parts; how long the kit actually lasts is in how long do solar panels last?. Here we cover what each warranty promises, what it excludes, what voids it, and what to ask before you sign.

The warranties on a typical UK solar install

A blank or vague row in this table is the question to ask.

Warranty	Who gives it	Typical length	What it covers	What it does not	What to check
Panel product	Panel manufacturer	10–15 years; some brands 25	Manufacturing defects: delamination, glass failure, junction boxes, hot spots	Storm, impact, bird and pest damage; cleaning or third-party work	Labour and shipping included? Registered in your name?
Panel performance	Panel manufacturer	25–30 years	Output below a stated linear curve, around 85–88% of rated output at year 25	Normal fading above the curve; shade, dirt, a faulty inverter	How a claim is proven, and who pays for testing
Inverter	Inverter manufacturer	5–10 years; extendable to 15–20 for a fee	Failure or fault of the unit	Often the labour to swap it; surges; unapproved battery pairings	Is an extension priced in?
Battery	Battery manufacturer	10 years or a cycle or throughput cap, whichever first	Faults, and usable capacity below a retained figure, often 60–70%	Fading inside the curve; use outside temperature limits	Usable capacity, cycle cap, retained figure
Mounting	Mounting manufacturer	10–20 years	Rails, hooks and fixings against corrosion and failure	The roof itself; installation errors	A named system, not unbranded rail
Workmanship	Installer	1–10 years	The install: roof penetrations, leaks, wiring, fixings, commissioning	Product faults; anything promised verbally	Length, and what backs it
Financial protection (IBG or MCS product)	Insurer via RECC or HIES on older installs; MCS approved product under the redeveloped scheme	IBG often 2–10 years; MCS product at least 6	Deposit and workmanship if the installer ceases trading; the MCS product adds design failure	Product faults; installers who held neither at the time	Which one applies, and a certificate in your name
Consumer law	Statute	6 years in England and Wales, 5 in Scotland	Consumer Rights Act 2015; Section 75 card protection over £100	Nothing expires, but you need evidence	Pay at least part by credit card

Three rows deserve a closer look. The performance warranty is the longest number on any quote and the weakest in practice. It only pays if output drops below the stated line, typically 85–88% of rated output at year 25, and a panel fading at the usual 0.5% a year sits comfortably above it. Proving a breach means removing a panel and flash-testing it in lab conditions, usually at your cost first, so successful claims are rare.

The inverter warranty is short and likely to be tested, because the inverter is the component most likely to fail inside a 25-year system. Most mainstream brands sell extensions to 15 or 20 years for a few hundred pounds. Microinverters and optimisers often carry 25-year terms; see solar inverter types explained.

The battery warranty is a race between clocks, "10 years or 6,000 cycles, whichever comes first", plus a retained-capacity figure: at 60–70%, the manufacturer only acts once usable capacity falls below that share of the original. The real-world version is in how long does a solar battery last?.

Financial protection, and the law beneath it

A workmanship warranty is a promise from a company, and if the company stops trading the promise stops with it. The layer underneath has recently changed. Older installs typically carry an insurance-backed guarantee (IBG) through the installer's RECC or HIES membership, which MCS used to require; both codes protect deposits and back workmanship with insurance, with slightly different mechanics and cover lengths. Under the redeveloped MCS installer scheme, consumer-code membership is no longer mandatory; instead every installer must buy an MCS approved financial protection product per installation, covering deposits, workmanship and design failure for at least six years if the installer ceases trading or refuses to put things right. Many installers still hold RECC or HIES voluntarily, so a 2026 quote may carry both. Either way, if the installer is gone and the roof leaks, you claim against the product, not the company. Ask which one applies and get the certificate itself, not a line in the contract saying one exists. The codes are compared in MCS, RECC and HIES explained and the scheme change in MCS vs NICEIC vs RECC.

Underneath sits the Consumer Rights Act 2015, which applies whether or not anyone wrote a warranty: goods must be of satisfactory quality, services must be carried out with reasonable care and skill, and you have up to six years to bring a claim in England and Wales, five in Scotland. Pay any part of the bill by credit card on a system costing £100–£30,000 and Section 75 of the Consumer Credit Act 1974 makes the card issuer jointly liable with the installer, which survives the installer's collapse.

How to read a warranty document

Read these before the headline number:

• Whose name it is in. Some installers register manufacturer warranties in their own name, or not at all. Ask for every warranty to be registered to you, with proof in the handover pack.
• Labour and shipping. Many product warranties cover the replacement part and nothing else. Getting a failed panel off a roof, shipped and refitted can cost more than the panel.
• The claims route. Who you call first, in what form, and within what time. A 30-day notice clause is easy to miss while waiting for the installer to ring back.
• The exclusions. Expect bird and pest damage, storm and impact, lightning and surges, coastal corrosion, pressure washing, and work by any unapproved third party.

What invalidates a warranty

Most voided warranties are voided by paperwork or well-meaning changes, not defects:

• Unapproved modifications. Adding a battery from a different brand to a hybrid inverter, wiring in a plug-in kit, or letting a non-solar electrician alter the DC side can all void the inverter warranty.
• The wrong installer. Some manufacturers only honour the full term when an MCS-certified or brand-approved installer fitted the system; otherwise a 25-year product warranty can quietly drop to a 10–12 year default.
• Missing registration. Several manufacturers require registration within 30–90 days for the extended term to apply. If the installer was meant to do it, get proof.
• Missing evidence. Serial numbers, the installation date, the invoice and commissioning photos are what a claim rests on.

If the installer stops trading, or you sell the house

If the installer goes bust, the manufacturer warranties survive and the workmanship warranty does not, unless an IBG or the MCS financial protection product stands behind it, in which case the provider steps in. The full treatment is in what if my solar installer goes bust?.

If you sell, most warranties pass with the property. Panel, inverter and battery warranties attach to the equipment and normally transfer, and financial protection is typically tied to the property rather than the person. Check the installer's own workmanship warranty, as some are personal to the original buyer. Keep the handover pack intact for completion; the wider process is in selling a house with solar panels.

Warranty questions for the quote stage

These sit alongside the eight questions to ask before signing:

• What is the workmanship warranty, in years, and what does it cover? Anything under two years is a flag.
• What stands behind it, an RECC or HIES insurance-backed guarantee or the MCS approved financial protection product, and will I receive the certificate in my name?
• Is my deposit protected, and by whom?
• Panel product and performance terms, by brand and model, as two separate numbers.
• Inverter term as quoted, and the price of extending it to 15 or 20 years.
• If a panel fails in year seven, who do I call, and who pays the labour?

Choose an installer whose MCS certificate is real and deposit and workmanship protection come with the package, because MCS requires an approved financial protection product on every installation and many installers add RECC or HIES on top. Every installer listed on Solarable holds a verified MCS certificate; the checks are in how we vet installers. Then get the answers above in writing and keep the handover pack. Earlier in the process, start with the roof: our roof check estimates direction and sun for your address, the savings calculator sizes the return, and listed installers covering your postcode will confirm both with a survey and a written quote.

Frequently asked questions

How long is a solar panel warranty in the UK?

Two warranties come with the panels. The product warranty covers manufacturing defects and typically runs 10–15 years, with some premium brands offering 25. The performance warranty promises output will stay above a stated curve, commonly around 85–88% of rated output at year 25, and typically runs 25–30 years. Both come from the manufacturer, not the installer.

Does a solar panel performance warranty actually pay out?

Rarely, and by design. It only pays if output falls below the stated curve, and a panel fading at the usual 0.5% a year sits well above it. Proving a breach means removing the panel and flash-testing it in lab conditions, usually at your own cost in the first instance, and the remedy is often a replacement panel without labour.

How long should a solar inverter warranty be?

Standard cover is typically 5–10 years, and the inverter is the component most likely to fail inside a 25-year system, so that gap matters. Most mainstream manufacturers sell extensions to 15 or 20 years for a few hundred pounds, and a quote that includes one is worth more than a cheaper quote that does not. Microinverters and optimisers often carry 25-year terms as standard.

What is an insurance-backed guarantee for solar panels?

It is third-party cover that honours the installer's deposit and workmanship promises if the installer stops trading. Older installs usually carry one through the installer's RECC or HIES membership. Under the redeveloped MCS scheme, consumer-code membership is no longer mandatory; instead every installer must buy an MCS approved financial protection product per installation, covering at least six years. Ask which applies to your quote and get the certificate in your own name.

Related

• What if my solar installer goes bust?
• MCS, RECC and HIES explained
• Eight questions to ask before signing a solar quote
• How long do solar panels last?
• Selling a house with solar panels
• Find listed installers covering your postcode