How Long Do Solar Panels Last? Degradation, Warranties, Inverters
Updated 30 October 2026 · SEO-DONS LTD
A solar system is a long-term purchase, so its lifespan matters as much as its price. The short answer is that panels last decades but lose a little output each year, while the inverter needs replacing partway through. This guide puts numbers on both from primary sources, and links each to the warranty that covers it. For how the warranties fit together, see solar panel warranties.
How long each part lasts
| Part | Expected life | Source |
|---|---|---|
| Solar panels | 25 years or more | Energy Saving Trust |
| Inverter | replace after around 12 years | Energy Saving Trust |
| Mounting rails and cabling | should match the panels | installer’s design |
Degradation: how output falls over time
Panels lose output slowly as they age. Manufacturers publish the rate on the datasheet, together with the minimum output they guarantee at the end of the power warranty. These are the figures from three premium panels sold in the UK:
| Panel | First year | After year 1 | Guaranteed at end of term |
|---|---|---|---|
| REC Alpha Pure-RX | 98% of rated power in year 1 | 0.25% a year | 92% at year 25 |
| AIKO Neostar 2P | 1% loss in year 1 | 0.35% a year to year 30 | 88.85% at year 30 |
| LONGi Hi-MO X10 | see the datasheet for your model | see the datasheet for your model | 88.85% at year 30 |
The REC and AIKO figures are from their datasheets; the LONGi end-of-term figure is from LONGi’s own announcement. Read 30 October 2026.
What this means in practice: AIKO’s figures add up exactly to its promise. Lose 1% in year one, then 0.35% a year for the next 29 years, and the panel still delivers 88.85% of its rated power at year 30. The starting figure for your roof is the generation estimate on your quote.
Why the inverter matters most
The inverter converts the panels’ direct current into the alternating current your home uses. It is the part most likely to need replacing: the Energy Saving Trust says after around 12 years. Budget for one replacement over the life of the system, check the inverter warranty term separately from the panel warranty, and keep an eye on the monitoring app, because a sudden drop in output usually points to the inverter. See solar inverters for the different types and what each costs to replace.
What makes panels last longer
- A good installation. Correct fixings, watertight roof penetrations and tidy cabling avoid most early failures. Check the installer’s workmanship warranty and whether it is insurance-backed.
- Monitoring. Compare each month with the same month last year. Catching a fault early saves months of lost output.
- Shade management. Trees grow; trimming them keeps output up.
- Sensible cleaning. Rain rinses tilted panels. Clean only if output has dropped and dirt is the cause, and never climb on the roof yourself. See maintenance and aftercare.
Which warranty covers what
| Warranty | Covers | Typical term |
|---|---|---|
| Panel power (performance) | a minimum share of rated output over time | 25 to 30 years |
| Panel product | manufacturing defects | varies by brand; read the datasheet |
| Inverter | the inverter unit | usually much shorter than the panels |
| Workmanship | the installation itself | set by the installer |
Some longer manufacturer terms only apply if the installer registers the system. REC’s ProTrust terms, for example, apply to panels installed by an REC Certified Solar Professional and registered with REC. Ask your installer to confirm any registration in writing.
The bottom line
Expect panels to work for 25 years or more and to keep most of their output. The datasheet tells you how much. Plan for an inverter replacement, choose an installer whose workmanship is backed by insurance, and compare panels on their end-of-term promise as well as their efficiency, using best solar panels in the UK.
If you have a question about a quote or a system you already own, send it through the form: your enquiry comes to SEO-DONS LTD and we reply by email.
Sources: Energy Saving Trust solar panels advice; REC Alpha Pure-RX datasheet; AIKO Neostar 2P datasheet (DS_EN_2405_V1.1); LONGi Hi-MO X10 announcement. Read 30 October 2026.