Solar panel warranty: the expert guide

Solar panels are a big investment, so you need to know what to do if things aren't quite working as they should.

In this guide, we’ll help you understand the essentials of solar panel warranties - including what’s covered, what’s not covered, how long they last, and the best ways to make sure your investment is protected.

If you’re wondering how much a solar & battery system could save you on your energy bills, answer a few quick questions below and we’ll provide you with an estimate.

Do solar panels come with a warranty?

Yes, solar panels usually come with warranties to protect your investment. They cover manufacturing flaws, guarantee panel efficiency for a certain period of time, and also address problems caused by installation.

These warranties, however, rarely offer sufficient coverage on their own. They offer a decent starting point, but don’t provide protection against things like accidental damage, severe weather, and general wear and tear.

That’s where the 20-year Sunsave Guarantee comes in, which is designed to provide total peace of mind (more on this further down).

The three types of solar panel warranty

When you have solar panels installed, you’ll typically encounter three types of warranty. These are:

1. Product warranty
2. Performance warranty
3. Workmanship warranty

Two of these - product and performance - are provided by the panel manufacturer, while the third, a workmanship warranty, is provided by the installer.

Let’s dive into the details. 

1. Product warranty

A solar panel’s product warranty is the manufacturer’s assurance that the product is free from flaws or defects that could impact its power output, protecting customers from problems caused by the panel’s production process. 

This type of warranty typically covers faults like glass breakage caused by internal defects, or malfunctioning internal components that prevent the panel from generating power effectively.

However, there are many limitations; product warranties exclude damage caused by external factors like accident, vandalism, fire, or extreme weather (e.g. hailstones or strong winds). 

What’s more, making a claim on your panel’s product warranty can involve a lot of paperwork/emails and waiting around. 

How long does it last?

Most solar panel manufacturers offer product warranties ranging from 12 to 25 years. 

However, a small handful go above and beyond, offering extended product warranties that last 30 to 40 years.

2. Performance warranty

A solar panel’s performance warranty guarantees that the product will maintain a certain level of power output for a stated period of time. This warranty accounts for the natural degradation of solar panels, ensuring that their efficiency remains within acceptable limits as they age.

Most manufacturers promise that their panels will degrade at a rate of no more than around 0.5% per year, meaning that after 30 years, the panel should still produce approximately 87% of its original output.

Over time, the backsheet and other components of the panel deteriorate due to daily UV radiation exposure and other environmental effects, causing a gradual drop in performance.

Moreover, a phenomenon called Light-Induced Degradation (LID) affects solar panels as soon as they're installed. In the first year, LID causes a 1-3% reduction in panel output, with the degradation rate subsequently slowing to a more stable level.

Like product warranties, performance warranties only tend to cover issues related to manufacturing, and come with exactly the same exclusions (e.g. accident, vandalism, fire, weather). 

How long does it last?

A performance warranty usually lasts between 25 to 30 years, which is longer than the majority of product warranties.

For most solar panels, manufacturers guarantee that the output will remain at somewhere between 80-90% of the module’s original level by the end of the warranty period. 

But some manufacturers go beyond this, offering guarantees of over 90% performance after 25 or 30 years.

Typical degradation of a solar panel over 30 years

3. Workmanship warranty

A workmanship warranty protects you against issues that later emerge from a dodgy or faulty solar panel installation, as opposed to defects in the panels themselves.

The workmanship warranty is critical because even the highest-quality panels won't perform as expected if they're not installed properly. A shoddy installation can result in faulty wiring, structural damage, or a leaky roof, causing electrical issues, fire hazards, or reduced output.

This warranty typically covers the labour and materials required to fix the above issues, ensuring that the installer takes responsibility for their work. 

How long does it last?

To be certified by the Microgeneration Certification Scheme (MCS) or Flexi-Orb - which any good installer will be - installers must offer a minimum two-year workmanship warranty to all of their customers.

Consequently, every workmanship warranty on the market is at least two years long, with some going up to 10 years. Given that solar panels tend to last around 30-40 years, a two-year workmanship warranty might cover just 5% of your system’s lifespan.

We offer Sunsave Plus, the UK’s first solar subscription, which means you can switch to solar with no upfront cost, and your system will also be protected by the 20-year Sunsave Guarantee - which means extremely comprehensive maintenance support on top of the basic warranties that everyone else gets. 

You can find out more about the Sunsave Guarantee further down the page, and you can enter a few quick details here to sign up for Sunsave Plus. 

How to make a claim on your solar panel warranty

If you notice an issue with your solar panels, the first step is to contact your installer so they can walk you through the claims process. They may ask for more details about the problem and, if they’re a particularly good installer, they’ll help you raise the claim directly with the manufacturer.

You must submit your warranty claim in writing (usually via email) to the manufacturer within the warranty period. You’ll also need to provide evidence and supporting documents, which tend to include:

• A detailed description of the issue
• Photos or performance data showing the problem
• The serial number and model of the affected panel(s)
• Proof of purchase
• The location of the installation

In some cases, the manufacturer may ask you to ship the defective parts back to them for inspection, or they might send a technician to inspect it onsite.

If the manufacturer approves your claim, they will usually take one of the following actions:

1. Repair the defective part(s): The manufacturer will prepare a repair plan and fix the affected panels.
2. Replace the defective part(s): They may provide new or additional panels to make up for any loss in power output.
3. Refund the residual value: The manufacturer might refund the remaining value of the defective panels and/or compensate for the output gap between the guaranteed and actual performance.

It’s important to act quickly if you notice an issue, as delaying a claim could cause further problems that might not be covered under the warranty. Always follow the manufacturer’s guidelines and don’t attempt repairs yourself, as this could void your warranty.

What voids your solar panel warranty?

Once you’ve had your solar panel system installed, it’s very important to read your manufacturer’s documentation and make yourself aware of what can void the warranties.

For starters, it's crucial to keep your proof of purchase and to avoid changing or damaging the product's identifying information (type, nameplate, or serial number), as this will invalidate the warranty.

While you're unlikely to cause physical issues yourself, a sloppy installer could void your warranty by mishandling the panels during transportation/setup, using substandard or mismatched parts, or exposing the panels to excessive voltage or power surges. 

Similarly, any installer who comes back to your property to perform maintenance on the solar panels is also at risk of voiding your warranties if they don’t treat them with due care. 

That’s why it’s crucial to choose one of the best solar panel installers, both for your initial installation and for future repairs or maintenance.

Finally, using abrasive tools or harsh chemicals to clean your solar panels can also damage them and invalidate the warranty. It’s vital that you always use a soft brush and gentle cleaning liquids to keep them in good condition - or pay for the services of professional solar panel cleaners.

For more information, check out our guide to cleaning your solar panels.

What happens if your solar panel manufacturer goes bust?

If the manufacturer of your solar panels goes out of business, your warranty is likely to disappear with it.

Bankruptcy law treats warranties as unsecured liabilities, meaning they're unlikely to be paid and may be written off completely. This can leave solar panel owners without any recourse for repairs or replacements if their panels develop faults.

To protect yourself, it’s a good idea to buy from a warranty-insuring manufacturer. These manufacturers insure their warranties through a third party, ensuring that the warranty will still be honoured even if the company goes bankrupt.

Another smart step is to pay for some, or all, of your solar panels with a credit card. In the UK, purchases made with a credit card between £100 and £30,000 are protected under Section 75 of the Consumer Credit Act 1974.

This means that if the manufacturer goes belly up, you may still be able to claim a refund or compensation from your credit card provider. Section 75 holds the credit card company equally responsible for making things right if something goes wrong, giving you an extra layer of protection.

However, it’s important to note that this protection only applies if you pay directly with your credit card, not through a third-party payment processor (e.g. PayPal) or using a money transfer from your credit card.

What happens if your installer goes bust?

If your installer stops trading after your installation, it can leave you in a tricky situation if something goes awry with their work. It’s critical to choose an installer that offers an insurance-backed guarantee (IBG) to avoid future problems claiming on your workmanship warranty.

An IBG is an insurance policy that protects the workmanship guarantee provided by your installer. It essentially transfers the liability from the installer to the insurer, ensuring that your investment is protected even if the original company is no longer around.

According to the consumer codes of both MCS and Flexi-Orb, all accredited installers must provide an IBG to ensure that the workmanship warranty will still be honoured if they stop trading during the term of the guarantee.

However, if your installer has gone bust and there’s no IBG in place, you’ll have to rely on new installers for maintenance or repairs. This means you’ll need to pay for these services out of pocket, including the cost of any necessary scaffolding, which can be very expensive. 

And even if you do have an IBG, it may well last just ten years, which will still leave you paying for pricey repairs if anything happens after that time. 

Introducing the Sunsave Guarantee

Most solar panel warranties are pretty limited. The product and performance warranties tend to come with a long list of exclusions, and even the better workmanship warranties are only about 10 years long.

Switching to solar brings with it some fairly major maintenance requirements. Some technical experts in the industry estimate that a solar & battery system will require three maintenance call-outs in the first 20 years; one for the panels, one for the battery, and one for the inverter.

Without any kind of lasting protection, having to sort out inspections, repairs and replacement parts can be a lot of expensive hassle.

That’s why every Sunsave Plus system is protected by the Sunsave Guarantee, which provides total peace of mind. Here’s what’s included:

• 30-year performance warranty on the solar panels
• A free battery replacement once it performs at less than 70% of its original capacity – typically after 10-12 years
• A free inverter replacement whenever required (usually after 10-12 years)
• 24/7 monitoring of the solar and battery system, including alerts if something isn’t working
• Troubleshooting of any issues.
• Management of any warranty claims on your behalf
• Insurance – your system will be insured by Aviva against damage, fire, and theft.
• Downtime protection – we’ll compensate you for any extended period of time that your system isn’t working as it should.

We’ve also taken important steps as a business to ensure that you can always rely on the Sunsave Guarantee. You can learn more about this here.

To find out how much you could save with a solar & battery system, provide a few quick details below and we'll get in touch with an estimate.

Solar panel warranty: FAQs