The four layers of cover
| Warranty | From | Covers | Typical term |
|---|---|---|---|
| Panel product | Manufacturer | Manufacturing defects in the panel | Brand-dependent, roughly 15–30 years; read the datasheet |
| Panel power (performance) | Manufacturer | A minimum share of rated output over time | 25–30 years, with an end-of-term percentage |
| Inverter | Inverter maker | The inverter unit | Usually much shorter than the panels; extensions are sometimes offered |
| Workmanship | Installer | The quality of the installation | Set by the installer; ask for it in writing |
What real datasheets promise
- REC Alpha Pure-RX (450–470W): 25-year power warranty; 20-year product warranty standard, 25 years under REC ProTrust (registered installs by an REC Certified Solar Professional). Output: 98% in year 1, then 0.25%/yr; 92% at year 25.
- AIKO Neostar 2P (500–525W, 60-cell): degradation of 1% in year 1, then 0.35%/yr to year 30. 30-year linear performance warranty (88.85% at year 30, per the datasheet chart); check the product-warranty term on the datasheet for your exact model.
- LONGi Hi-MO X10 (back-contact): 30-year linear power warranty; product term varies by variant (LONGi quotes 15 years on the variant it describes). LONGi states 88.85% of output retained at the end of its 30-year power warranty.
The lesson: two panels with “25-year warranties” can promise quite different things. Compare the end-of-term output percentage and the product term, not the headline. For the lifespan behind these numbers, read how long solar panels last, including when to expect an inverter replacement.
Insurance-backed warranties
An insurance-backed warranty, offered through schemes such as HIES, has an independent insurer stand behind the installer’s workmanship warranty and, depending on the policy, your deposit. It pays out only if the installing company has genuinely ceased trading. That is a narrow trigger, but it is the risk that matters most over a 25-year system life.
Consumer codes such as RECC and HIES also set rules on deposits and give you an independent route for complaints. Check membership in the code’s own directory.
Conditions that catch people out
- Registration. Longer manufacturer terms can depend on the installer registering the system. REC’s ProTrust terms, for example, apply only to panels installed by an REC Certified Solar Professional and registered with REC.
- Labour. A product warranty may replace the panel but not pay for scaffolding and labour to swap it.
- Modifications. Unapproved changes, or a non-certified installation, can void cover.
- Who honours it. If the installer is gone, can you claim from the manufacturer directly, and does it have a UK contact?
Get every warranty listed on the quote, with its term and who honours it. The quotes checklist includes this. For inverters specifically, see solar inverters.