A solar installation should keep cutting your electricity costs long after the scaffolding has gone. That is why a solar panel warranty guide matters before you choose a system, not only when something goes wrong. The right cover protects the equipment, the expected energy output and the standard of installation – three separate areas that can affect the value of your investment.
For homeowners, landlords and businesses, warranties can look reassuring on a quotation but vary considerably between manufacturers and installers. A long headline warranty is useful, but only if you understand what it covers, what it excludes and who will deal with a fault.
The three warranties that matter most
Most solar PV systems come with a combination of product, performance and workmanship warranties. Each plays a different role, and one does not replace the others.
Product warranty: cover for the panel itself
A product warranty covers faults in the physical solar panel caused by manufacturing defects. This may include defective materials, faulty junction boxes, frame issues or panel failures that occur under normal use.
Many reputable panel manufacturers offer product warranties of 15 to 25 years. Some premium panels provide longer cover, but the number alone should not be the deciding factor. Check which company is standing behind the warranty, whether it has an established UK presence and whether the terms include parts, labour and transport.
A replacement panel may be supplied under warranty, for example, while the cost of safely removing and refitting it is not. That can leave the property owner with an unexpected bill. Asking this question before installation gives you a clearer view of the protection you are actually receiving.
Performance warranty: protection against excessive degradation
Solar panels gradually produce a little less electricity as they age. This is normal. A performance warranty, sometimes called a power output warranty, confirms the minimum level of output a panel should retain over time.
A common arrangement is a 25 to 30-year performance warranty, with a promise that the panel will still deliver a stated percentage of its original rated output at the end of that period. For example, a manufacturer may guarantee 80% to 90% output after 25 years, depending on the panel range.
This does not mean your panels will stop working when the warranty ends. Well-installed solar panels can continue generating electricity for many more years. It means the manufacturer has set a threshold for acceptable degradation. If the panel falls below it, subject to the warranty conditions, you may have a claim.
Performance claims are often more involved than product claims. Output can be affected by shading from new trees or neighbouring buildings, dirt, damaged wiring, inverter faults and changing weather conditions. The panel must usually be tested to show that the issue is the panel itself rather than the rest of the system.
Workmanship warranty: cover for the installation
The workmanship warranty is provided by your installer and covers the quality of the installation work. It is particularly valuable because a solar PV system depends on more than the panels. Mounting equipment, roof penetrations, cabling, electrical connections, isolators and system commissioning all need to be completed correctly.
Workmanship cover commonly lasts between two and ten years, although terms differ between installers. It may cover faults resulting from installation errors, such as loose fittings, poor cable routing or issues with roof weatherproofing caused by the installation work.
It does not normally cover an existing roof defect, storm damage, accidental damage or faults in a manufacturer-supplied component. Before work begins, make sure you know precisely how long the workmanship warranty lasts and how to contact the installer if you need support later.
Do not overlook inverter and battery warranties
Panels are the most visible part of a solar system, but they are not the only components with warranties. Your inverter converts the direct current generated by the panels into usable electricity for your property. As it is a working electronic component, it usually has a shorter warranty than the panels.
An inverter warranty may be between five and 12 years as standard, with extension options available on some models. If your system includes solar battery storage, the battery will also have its own terms. These may be based on years of cover, total energy throughput, retained capacity or a combination of all three.
EV chargers, monitoring equipment and optimisers can have separate cover as well. A complete quotation should make this easy to understand rather than leaving you to piece together several manufacturer documents after installation.
What can invalidate a solar panel warranty?
Warranties are designed to cover genuine faults, not every issue that happens during the life of a system. The exclusions deserve as much attention as the headline term.
Damage caused by severe weather, fire, vandalism, accidental impact or unauthorised alterations is commonly excluded. A panel damaged by a fallen branch, for instance, is generally an insurance matter rather than a manufacturer warranty claim. Problems caused by neglect, misuse or cleaning with unsuitable equipment may also fall outside cover.
Changes to the system can create complications. If another contractor moves panels during roof repairs, alters wiring or adds equipment that is not compatible with the existing system, the manufacturer or original installer may not accept responsibility for a later fault. Always obtain advice before changing any part of the solar array.
Poor access is another practical consideration. If a warranty replacement is approved, check whether scaffolding, access equipment and labour are included. These costs can be significant, especially for larger commercial arrays or difficult roof layouts.
What to check before signing a solar quotation
A reliable installer should be able to explain your warranties in plain English. You should receive written confirmation of the panel manufacturer, product warranty length, performance guarantee, inverter cover, battery cover where applicable, and the installer workmanship warranty.
Ask who handles a claim in the first instance. In many cases, your installer will assess the issue and contact the manufacturer if required. This is far simpler than being left to deal directly with an overseas manufacturer or a generic support portal.
It is also worth checking whether the warranty can transfer to a new owner if you sell the property. Transfer terms vary, and some manufacturers require registration or notification within a set period. For landlords and property developers, this can be especially relevant when assets change hands.
Keep copies of your quotation, invoice, system specification, commissioning documents, warranty certificates and serial numbers. Store them digitally as well as in paper form. A clear record helps if you need to raise a claim, sell the property or arrange insurance.
Warranties, MCS certification and your legal rights
MCS certification is a useful sign that an installation has been designed and fitted to recognised standards. It supports quality and can be relevant where eligibility for schemes or export arrangements depends on certified installation. However, MCS certification is not itself a warranty and does not replace product or workmanship cover.
Your statutory consumer rights also exist alongside a warranty. In England and Wales, consumers can generally bring a claim for breach of contract for up to six years, while the period is generally five years in Scotland. The detail depends on the contract, the fault and the circumstances, so warranty wording should never be treated as the only protection available to you.
For greater reassurance, choose an installer that provides clear documentation, uses established equipment brands and remains available to support the system after commissioning. A cheap quote that leaves gaps in responsibility can prove more costly than a properly specified installation.
How to make a warranty claim
If you believe there is a fault, start by checking your monitoring app or generation meter and noting any error messages. Take photographs if there is visible damage, but do not attempt electrical repairs or remove panels yourself.
Contact the installer with your system details, a description of the issue and any relevant photographs or screenshots. They can identify whether the likely cause is a panel, inverter, battery, wiring issue or a change in site conditions. If a manufacturer claim is needed, the installer can usually provide the technical evidence required.
Act promptly. Leaving an inverter fault unresolved can reduce generation for months, directly affecting the savings your system was installed to deliver. Regular monitoring makes it easier to spot a sudden drop in output and deal with it early.
A well-chosen solar system should offer more than clean electricity and lower bills. It should give you confidence that the equipment and installation are backed by clear, practical support for the years ahead.