How long do solar panels last? 25 to 30 years, in practice
Solar panels last 25 to 30 years under a mainstream performance warranty, degrading on a published curve and needing very little from you along the way. The inverter runs on a shorter clock, and a manufacturer warranty is only worth as much as the manufacturer. Here is what each of those actually means in practice.
Updated 25 September 2026 · written by the Clearline guidance team · 7 min read
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.
| Age | Output vs original | Per 1,000 kWh of original annual output |
|---|---|---|
End of year 1 | 99% | 990 kWh |
Year 10 | 95% | 955 kWh |
Year 15 | 94% | 936 kWh |
Year 25 | 90% | 899 kWh |
Year 30 | 88% | 881 kWh |
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.
The panels are rarely what fails
Put a price on that decay and it is modest. If every one of those 1,000 kWh displaced imported electricity at 26.32p, the average capped unit rate for 1 October to 31 December 2026, the 119 kWh lost by year 30 is worth around £31 a year. The component that will actually cost you money in that window is the inverter, and it is the line on the quote most homeowners never ask about.
- Product warranty
- 15 years under the signed LONGi Limited Warranty; LONGi's UK and Ireland datasheet shows 25 years for this market
- Performance warranty
- 30 years, front side only
- Output retained at year 30
- At least 88.85 per cent
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.
Roof access is the expensive part
Scaffolding on a solar job runs from about £300 to over £1,000 and accounts for roughly 13% of a typical install cost, usually staying up for around two weeks on a two to three day job. That is the arithmetic to keep in mind before anyone goes up for a task that could be bundled with other roof work.
Not sure whether your output has genuinely drifted or your inverter is on the way out? The free remote design call reviews the system you already have before anyone quotes you for work on it.
Get my free quote →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.
| Component | Warranty term | Condition attached |
|---|---|---|
Enphase IQ8 microinverter | 25 years | One unit per panel, 97.5% CEC efficiency, each panel operates independently |
SolarEdge S440 and S500 optimiser | 25 years | Requires a SolarEdge inverter; gives module level shutdown and monitoring |
Tigo TS4-A-O optimiser | 25 years | Only when internet connected with Tigo monitoring. Otherwise 5 years |
Hybrid or string inverter | Varies by manufacturer | Typically shorter than the panel terms. Get the exact figure in writing |
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.
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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.
| Panel | Product warranty | Performance warranty | What the performance warranty guarantees |
|---|---|---|---|
Trina Vertex S+ (NEG9R.28) | 25 years | 30 years | Linear power warranty; read the end of term figure on the SKU datasheet |
JA Solar DeepBlue 4.0 N-type | 25 years | 30 years | 87.4% of original output at year 30 |
REC Alpha Pure-RX | Up to 25 years under ProTrust, covering product, performance and labour when fitted by an REC certified installation team | 25 years | 92% of original output at year 25 |
Mainstream 2026 N-type, as a band | Varies by series and market | 25 to 30 years | 87% to 92% of original output at end of term |
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. We offer a free remote design call, and every system is installed and commissioned by our own MCS-certified, fully insured installation teams.
Maintenance and warranty questions, answered
How long do solar panels last?
Mainstream N-type panels carry performance warranties of 25 to 30 years, guaranteeing 87% to 92% of original output at the end of the term. The panel does not stop at that point. The manufacturer's promise does. On the standard curve of 1% or less in year one and 0.4% a year after, a module is still producing roughly 88% of its original output at year 30.
Do solar panels need cleaning?
Sometimes, but not on a schedule. Panels generate in proportion to the light reaching them, so what matters is anything opaque that stays put. Watch your monitoring against the same month last year: a slow few percent a decade is the warranty curve, while a step change is physical. There is no published UK cleaning interval worth quoting, so anyone selling you a fixed twice-a-year plan is selling a service rather than meeting a specification.
How often does a solar inverter need replacing?
We will not publish an interval, because the figures repeated around the industry do not trace back to a manufacturer document. What is documented is that string inverters carry shorter warranty terms than the panels and are the component most likely to need replacement within the panels' life, while module level electronics such as Enphase IQ8 microinverters and SolarEdge S-series optimisers carry 25 year terms. Ask for the warranty length on your specific inverter in writing.
What does a performance warranty actually pay out?
It guarantees your output stays above a published curve, and it triggers only when measured output falls below that line. That means the claim rests on evidence, so monitoring data matters. It is separate from the product warranty, which covers the panel physically failing, and separate again from the installation team's workmanship warranty on fixings, roof penetrations and wiring.
Does dirt on one panel matter more with a string inverter?
Yes. On a plain series string, all panels sit on one circuit and the string performs at the level of its weakest panel, so one badly soiled or shaded module drags the rest. With microinverters each panel operates independently, and with optimisers you get panel level monitoring so you can see which module is down. Some newer back contact panels also bypass individual shaded cells rather than losing the whole module.
What happens to my warranty if the manufacturer stops trading?
The hardware keeps working, but the claim route closes. When GivEnergy entered administration in April 2026 the installed kit carried on running because it does not depend on the company's servers, yet hardware warranties and software support were no longer honoured and customers were directed back to their installation teams. This is why the installation team's workmanship cover, and any insurance backed guarantee sitting with an insurer rather than the team, carry real weight.
Is there VAT on repair or replacement work?
Zero rate VAT applies to the supply and installation of energy-saving materials in residential accommodation until 31 March 2027, after which it reverts to the reduced 5% rate. That covers solar and battery installations. Whether a standalone repair or a like-for-like swap falls inside the relief depends on the work, so ask for the VAT treatment to be stated on the quote.
See the numbers next: LONGi 530 W panels, installed, or the solar panels guide.
Figures and specifications in this guide are sourced below and were checked on the date shown. Rates and product specifications change; we confirm the current picture on your free design call.
Sources
- Tiger Neo linear power warranty: 30 years, first year degradation of 1% or less, then 0.4% a year jinkosolar.com
- Trina Vertex S+ 25 year product and 30 year power warranty alternergy.co.uk
- JA Solar DeepBlue 4.0: 25 year product warranty, 30 year performance warranty to 87.4% of original output spectrumenergysystems.co.uk
- REC Alpha Pure-RX ProTrust warranty covering product, performance and labour, 92% output guaranteed at year 25 recgroup.com
- Enphase IQ8 microinverter: 25 year warranty, 97.5% CEC efficiency enphase.com
- SolarEdge S440 and S500 power optimiser datasheet: 25 year warranty, module level shutdown and monitoring solaredge.com
- Tigo TS4-A-O: 25 year warranty when internet connected with Tigo monitoring, otherwise 5 years tigoenergy.com
- Panels generate in proportion to light intensity sunsave.energy
- A series string performs at the level of its weakest panel energysage.com
- Longi Hi-MO X10 cell level shading design bypasses individual shaded cells solenenergy.com
- Scaffolding on a solar job: £300 to over £1,000, around 13% of install cost, typically up for two weeks spartek.co.uk
- GivEnergy entered administration 9 April 2026; hardware keeps working, warranties and software support no longer honoured ess-news.com
- Energy Storage Association guidance for GivEnergy customers esa-uk.org
- Zero rate VAT on energy-saving materials to 31 March 2027, then the reduced 5% rate gov.uk
- Ofgem price cap 1 October to 31 December 2026: 26.32p per kWh average capped electricity unit rate ofgem.gov.uk
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