Panels & output
Solar panel lifespan and warranties explained
Solar panels are long-lived, but they don't last forever and their output slowly declines. Two different warranties cover that — and they're easy to confuse.This guide explains lifespan, degradation and the two warranty types, so you can read a datasheet sensibly. For sizing, see the wattage guide.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
How long panels last
A solar panel doesn't usually fail suddenly; instead its output drifts down slowly over many years — a process called degradation. Well-made panels are designed to keep producing a useful share of their rated output well into a multi-decade life. The microinverter and other electronics generally have their own, shorter warranties, so the panel and the inverter ageing are worth thinking about separately — see solar inverters.
Product vs performance warranties
Manufacturers quote two different warranties and it's important not to mix them up. A product (or workmanship) warranty covers manufacturing defects and physical failure for a set period. A performance (or power) warranty is a promise about output: it guarantees the panel will still produce at least a stated percentage of its original rating after a given number of years.
| Warranty | What it covers | Why it matters |
|---|---|---|
| Product / workmanship | Defects and physical failure | Protects against faults in the panel itself |
| Performance / power | Minimum output after X years | Sets a floor on long-term generation |
What to check before buying
Don't assume headline numbers from one brand apply to another — figures vary, so read the specific datasheet. And remember the warranties cover the hardware, not the legal position: plug-in solar is not yet legal to use in the UK (legal status).
- The product warranty length, and what it actually covers.
- The performance warranty — the guaranteed output percentage and the year it applies to.
- Whether the warranty is honoured in the UK and by whom.
- The microinverter's separate warranty, which is usually different from the panel's.
Frequently asked questions
- How long do solar panels last?
- Quality panels are built to last decades, with output declining gradually rather than stopping. The exact expected life and the guaranteed output over time are set by each panel's performance warranty, so check the datasheet for the specific model.
- What is the difference between a product and performance warranty?
- A product (workmanship) warranty covers defects and physical failure for a set period. A performance warranty guarantees the panel will still produce at least a stated percentage of its original output after a given number of years. They are separate promises.
Sources
- 1. Microgeneration Certification Scheme — MCS
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