How long do solar panels last? 25 to 30 years, in practice

How long solar panels actually last

Solar panels last 25 to 30 years under a mainstream N-type performance warranty sold in the UK in 2026, which guarantees between 87% and 92% of original output at the end of that term. The warranty ending is not the panel ending. It is the point at which the manufacturer stops promising anything, and a module in good physical condition carries on generating past it.

The decay is slow and published. The industry norm is a first year drop of 1% or less, then about 0.4% a year after that. Both figures are written into the linear power warranty on the datasheet, which is where you should read them rather than taking a salesperson's summary.

Modelled on the 2026 mainstream N-type curve: 1% or less in year one, then 0.4% a year. Shown per 1,000 kWh of original annual output so it scales to any array. Your own panel's guaranteed curve is on its datasheet.

Cleaning: judge it on output, not on the calendar

Panels generate in proportion to the light reaching them, so anything opaque and persistent on the glass costs you output roughly in proportion to the area it covers. That is the whole mechanism. Everything else is a question of how much is on there, how long it stays, and whether your system tells you about it.

• One heavily soiled panel on a plain string costs more than a thin even film across the whole array, because a series string performs at the level of its weakest panel.
• Systems with microinverters or optimisers report per panel. That is what tells you a single module is down rather than the whole array having a quiet week.
• Newer back contact panels tolerate partial obstruction better than older designs. Longi's Hi-MO X10, for instance, bypasses individual shaded cells rather than losing the module's whole contribution.
• Watch the trend in your monitoring app against the same month last year. A gradual slide of a few percent a decade is the warranty curve doing its job. A step change is something physical.
• Treat a fixed twice-a-year cleaning schedule as a sales proposition rather than a specification. There is no published UK maintenance interval worth quoting at you.

The inverter runs on a shorter clock

Module level electronics carry warranty terms that match the panels. Central string inverters generally do not, and the string inverter is the component most likely to need replacing inside the panels' working life. Which one you have is decided at design stage, which is why inverter choice belongs in the first conversation rather than the twelfth year.

The long terms sit with the module level electronics. The shorter clock sits with the central inverter, and the Tigo row shows how a headline term can depend on something as mundane as keeping the monitoring online.

We are not publishing a typical string inverter replacement interval. The figures repeated around the industry are not traceable to a manufacturer document, and this is exactly the number a homeowner is most likely to budget around. Ask for the warranty term on the specific inverter in your quote, in writing, and plan from that.

What a warranty actually covers

• Product warranty. Covers the panel itself failing: manufacturing defects, delamination, cell faults. This is the shortest of the three on most modules and the one that varies most between series and market.
• Performance or power warranty. Guarantees output stays above a stated curve, typically 25 to 30 years ending at 87% to 92% of original output. It pays out only when measured output falls below that line, which means you need monitoring data to make a claim.
• Workmanship warranty. Comes from the installation team, not the manufacturer, and covers the fixings, the roof penetrations and the wiring. Different party, different term, and the one most likely to matter in the first five years.
• Labour and call-out. Frequently excluded from manufacturer cover, so a free replacement panel can still arrive with a bill for scaffold and a crew day attached.

Terms vary by SKU and by market, and several manufacturers publish different product warranty lengths for different series. Ask for the datasheet for the exact model named on your quote rather than the manufacturer's headline figure.

A warranty is only as good as the company behind it

GivEnergy was one of the larger British names in home storage until it entered administration on 9 April 2026 and ceased trading. Hardware already on walls kept working, because it does not depend on the company's servers to run. What stopped was the promise behind it: hardware warranties and software support are no longer honoured by GivEnergy Ltd, and customers were directed back to their installation teams, with the Energy Storage Association issuing guidance for affected households. Read that as a rule rather than a story about one brand. A 30 year performance warranty is a 30 year promise from a balance sheet, which is why the installation team's workmanship cover and any insurance backed guarantee matter more than the length of the number on the manufacturer's brochure.

Degradation, cleaning and inverter life all land in the same place, which is the number at the bottom of your bill. Our county pages each carry a local calculator that models generation and savings for that area, and our tariff guidance carries the date every rate was last checked. The solar panels hub covers specification and sizing, and the battery storage hub covers what changes once storage is added to an existing array.

Warranty terms, product specifications and rates checked 4 August 2026. Clearline gives independent guidance and a free remote design call. Installations are carried out by an MCS-certified installation team for your area.