What's the difference between a performance and product warranty?

Performance vs Product Warranties: What Solar Panel Buyers Need to Know

If you're considering solar panels for your home or business, you'll quickly encounter two types of warranties that might seem confusing at first glance: performance warranties and product warranties. Both are crucial for protecting your investment, but they cover completely different aspects of your solar system.

Product Warranty: Protection Against Physical Defects

Your product warranty is essentially insurance against manufacturing faults and physical problems with the panels themselves. This covers issues like cracked glass, corroded frames, faulty junction boxes, or any other physical component that might fail due to poor manufacturing.

Most reputable manufacturers now offer product warranties lasting 12 to 25 years, with many premium brands providing the full 25-year coverage as standard. Companies like LG, Panasonic, and SunPower typically offer these longer warranties because they're confident in their build quality.

What's covered: Frame damage, glass breakage, electrical connection failures, and any manufacturing defects that cause the panel to stop working entirely.

What's not covered: Damage from extreme weather, improper installation, or normal wear that doesn't affect function.

Performance Warranty: Guaranteeing Power Output Over Time

Performance warranties are about efficiency rather than physical integrity. Solar panels naturally degrade over time - it's perfectly normal physics - but manufacturers guarantee they won't degrade faster than expected.

Most performance warranties run for 25 to 30 years and guarantee that your panels will still produce around 80-90% of their original power output by the end of that period. The typical degradation rate is about 0.5% per year, though some premium panels degrade even more slowly.

For example, if you install 4kW of panels today, a performance warranty might guarantee they'll still produce at least 3.2kW after 25 years (80% of original capacity).

UK-Specific Considerations

In the UK, both warranties become particularly important given our variable weather conditions. The frequent temperature changes, occasional hail, and high winds can test both the physical durability and long-term performance of panels.

Your warranties typically require professional installation by MCS-certified installers to remain valid. This certification is already required for most government schemes anyway, so it shouldn't add extra cost, but it's worth checking before installation.

Some manufacturers also specify that panels must remain in their original location for warranties to apply, which could be relevant if you're planning home renovations or extensions.

Costs and Claims Process

Warranty claims shouldn't cost you anything upfront, but you might need to pay for diagnostic testing to prove a claim. Expect to pay £150-300 for professional testing if your installer can't determine the problem remotely.

Shipping costs for replacement panels vary by manufacturer. Some cover all costs, whilst others might ask you to pay for transport - potentially £50-150 depending on your location and the number of panels involved.

Common Mistakes to Avoid

Don't assume all warranties are created equal. Some manufacturers offer impressive headline warranty periods but have restrictive terms that make claims difficult. Always read the actual warranty document, not just the marketing summary.

Many people focus solely on the warranty length without considering the manufacturer's financial stability. A 30-year warranty means nothing if the company doesn't exist in 15 years to honour it.

Another mistake is not keeping proper documentation. Save your installation certificates, photos of the completed system, and any performance monitoring data from the first few months.

The Bottom Line

Both warranty types protect different aspects of your investment. Product warranties give you peace of mind about build quality and manufacturing defects, whilst performance warranties ensure your panels will keep generating the electricity you're counting on for decades.

When comparing solar quotes, don't just look at the warranty lengths - consider the manufacturer's reputation, the clarity of warranty terms, and whether they have a UK presence to handle claims efficiently. The best warranty is one you'll never need to use, but if you do, you want it to be straightforward and comprehensive.