PowerGuide

How Long Do Solar Panels Last? (UK 2026)

By Rob Hammond · Updated September 2026 · How we score

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Nobody can tell you how long a solar panel lasts, because the panels being sold in 2026 have not been on a roof for 25 years. What manufacturers will tell you, in writing and in a document you can hold them to, is how long they warrant the panel and how much output they guarantee along the way. That is a different question with a real answer, and it is the one this guide answers, from the four panels in our own catalogue and their manufacturers’ own datasheets.

Two warranties, and only one of them is about lifetime

Every panel datasheet carries two separate promises, and conflating them is the most common mistake in solar marketing.

The product warranty covers the physical panel: manufacturing defects, delamination, a failed junction box, a frame that corrodes. If it fails within the term the manufacturer replaces or repairs it. This is the shorter of the two, and it is the honest measure of how long the manufacturer expects the hardware to hold together without argument.

The performance (power) warranty covers output. It promises that the panel will still produce at least a stated percentage of its rated power in a given year, usually expressed as a first-year maximum loss plus a maximum annual loss thereafter. It does not promise the panel is defect-free. A panel can be out of product warranty and still inside its performance warranty, which is the usual position after year 15 on a mainstream module.

Here is what the four panels in our catalogue actually carry, read off the manufacturers’ documents on 21 September 2026:

PanelProduct warrantyPerformance warrantyFirst-year degradationAnnual thereafterGuaranteed at end of performance warranty
Aiko Neostar 2S (AIKO-A-MAH54Mb)25 years30 years≤1%≤0.35%/yr90.6% at year 25, 88.85% at year 30
Jinko Tiger Neo 3.0 (JKM460-485N-48QL6-DV)15 years30 years1%0.35%/yr88.85% at year 30
Trina Vertex S+ (TSM-440NEG9R.28)25 years30 years1%0.4%/yr87.4% at year 30
JA Solar DeepBlue 4.0 Pro (JAM54D40/LB)12, 15 or 25 years (depends on the SKU, see below)30 years1%0.4%/yr87.4% at year 30

Two things to say plainly about that table.

JA Solar’s product warranty depends on which SKU you are sold. jasolar.com still returns HTTP 403 to every automated request we make, but JA Solar’s European site, jasolar.eu, does load, and on 21 September 2026 it listed the DeepBlue 4.0 Pro LB module as three separate products, JAM54D40 LB 12Y, 15Y and 25Y, which are the same panel sold with different product-warranty terms. The datasheet linked from the 15Y page (JAM54D40/LB, version Global-EN-20240423A) prints “12-year product warranty” on its front page; the 25Y datasheet prints “25-year product warranty”. Both print the same power side: 30-year linear power output warranty, 1% first-year degradation, 0.4% a year thereafter, and 87.4% at year 30.

So the power half of that row is now read off JA Solar’s own documents. The product half is not a single number, and no JA Solar datasheet we can read prints 15 years. Our catalogue holds 15 because that is the variant name on the EU site, and we have left it there and said so rather than overwriting it with a figure from a different SKU. If you are being quoted a DeepBlue 4.0 Pro, ask which of the three variants it is and get the product-warranty term in writing; on this panel the difference between them is thirteen years of cover.

The Jinko product warranty really is 15 years. Its EU datasheet states “15 Year Product Warranty” and “30 Year Linear Power Warranty” side by side. That is a ten-year gap against the Aiko and the Trina on the part of the promise that covers the hardware, and it is the single most useful line in the table.

The degradation arithmetic

Warranted degradation compounds. The output in year n, as a fraction of the panel’s rating, is:

output in year n = (1 − first-year loss) × (1 − annual loss)^(n−1)

Run that to year 25 on each panel’s own stated curve, then sum all 25 years to get the total generation as a number of “full years” at the original rating:

PanelWarranted curveOutput in year 2525-year total (full years at rating)Average over 25 years
Aiko Neostar 2S99%, then 0.35%/yr0.99 × 0.9965²⁴ = 91.0%23.7494.9%
Jinko Tiger Neo 3.099%, then 0.35%/yr0.99 × 0.9965²⁴ = 91.0%23.7494.9%
JA Solar DeepBlue 4.0 Pro99%, then 0.4%/yr0.99 × 0.996²⁴ = 89.9%23.6094.4%
Trina Vertex S+99%, then 0.4%/yr0.99 × 0.996²⁴ = 89.9%23.6094.4%

Now put it in kWh. Our sizing guide works a 4.4kWp array of ten 440W panels on a south-facing Midlands roof at 35° pitch, which PVGIS puts at 4,360kWh in year one after 14% system losses. So:

  • Aiko or Jinko curve: 4,360 × 23.74 = about 103,500kWh over 25 years. Year 25 alone is 4,360 × 0.910 = 3,968kWh.
  • Trina or JA Solar curve: 4,360 × 23.60 = about 102,900kWh. Year 25 alone is 3,921kWh.

The gap between the best and worst warranted curve here is about 600kWh over 25 years: under 25kWh a year, worth roughly £6 a year at the Ofgem cap rate of 26.32p/kWh for 1 October to 31 December 2026. Degradation is not where the money is. It is worth knowing because it feeds the cost-per-kWh calculation in our cost guide, where 103,500kWh against a £7,238 install gives 7.0p/kWh, and it is worth checking because a panel with a much worse curve would show up immediately. It is not worth choosing a panel over.

One detail that shows these are legal documents rather than physics: on every datasheet we read the guaranteed figure sits slightly below the one you get by compounding the headline rate.

PanelCurve at year 25Guaranteed at year 25Curve at year 30Guaranteed at year 30
Aiko Neostar 2S91.0%90.6%89.4%88.85%
Jinko Tiger Neo 3.091.0%not marked on the chart89.4%88.85%
JA Solar DeepBlue 4.0 Pro89.9%not marked on the chart88.1%87.4%
Trina Vertex S+89.9%not marked on the chart88.1%87.4%

That is the sensible way round: the manufacturer leaves itself headroom rather than promising more than its own rate delivers. But it means the number you can actually enforce is the percentage printed on the warranty chart, not the one you calculate from the headline degradation rate. Aiko’s chart is the most useful of the four because it marks year 25 as well as year 30.

The inverter is the real lifetime cost

Panels are warranted for decades. The box they are wired into is not, and that gap is the honest answer to “how long before this costs me money again”.

From our inverters guide, which read the same manufacturers’ datasheets: Growatt’s SPH 3000-6000TL BL-UP states 5 years, with 10 years optional; the Solis S6-EH1P(3-8)K-L-PLUS datasheet we read carries no warranty row at all; Enphase’s UK IQ8 datasheet claims up to 25 years, conditional on an internet-connected IQ Gateway being installed and staying installed.

So a 25-year panel life spans at least one inverter product warranty, and on a Growatt’s five-year term it spans five. Somewhere in the second decade, probably earlier, a string inverter is replaced. That is not a defect; it is the design.

There is no official UK statistic for what a replacement inverter costs fitted, and we are not going to invent one. DESNZ publishes installed cost per kW for whole systems, not component replacement prices, and neither Solis nor Growatt publishes an RRP. Our catalogue carries the two hybrids at £966 and £950 as indicative catalogue estimates rather than quotes, and neither figure includes labour, scaffolding if the array has to be isolated, or re-commissioning. Treat any 25-year payback that ignores a replacement as optimistic, including the one our solar payback calculator produces, which is deliberately a hardware model rather than a lifetime one.

What efficiency actually means, and when it matters

Module efficiency is the fraction of the sunlight landing on the panel that leaves it as electricity, measured under standard test conditions: 1,000W/m² irradiance, 25°C cell temperature, AM1.5 spectrum. So 23% means 230W out of every 1,000W per square metre, in laboratory light your roof sees for a handful of hours a year.

It has nothing to do with lifetime. Two panels on the same warranted curve fade at the same rate whether they are 22% or 23.6% efficient. What efficiency decides is kW per square metre: how much capacity you fit in a fixed area.

Aiko’s NEOSTAR 2S54 datasheet gives module dimensions of 1,757 × 1,134 × 30mm, which is 1.99m². Trina’s TSM-NEG9R.28 and Jinko’s 48QL6 are both 1,762 × 1,134 × 30mm, essentially the same. So on roughly 2m²:

  • At 22.0%, you get a 440W panel, which is exactly what Trina’s datasheet lists for the TSM-440NEG9R.28, at 22.0% module efficiency.
  • At 23.02%, you get 460W, the bottom bin of Jinko’s EU 48QL6 datasheet, which runs 460–485W and 23.02–24.27%.
  • Aiko’s datasheet walks the same line across seven bins on one physical module: 440W at 22.1%, 445W at 22.3%, 450W at 22.6%, 455W at 22.8%, 460W at 23.1%, 465W at 23.3% and 470W at 23.6%. Same panel, same area; the “efficiency” is just the power bin restated.

That is the whole of it: one efficiency point is 10W per square metre, which on a 2m² module is about 20W per panel, exactly the step between each of Aiko’s bins. On a ten-panel roof, moving from a 22.0% panel to a 23.0% one buys you around 200W, or under 5% more capacity. Even Aiko’s 23.6% top bin against Trina’s 22.0% is about 320W across ten panels, under 8%. If your roof plane has room for an eleventh panel, the cheaper panel and one more of them wins. If it does not, efficiency is the only lever you have, and that is the tight-roof case where paying for it is rational.

One note on our own data, since we checked it against the datasheets while writing this. Our catalogue listed the Aiko at 445W/23.2%, and Aiko’s own datasheet contradicts that directly: its 445W bin, the AIKO-A445-MAH54Mb, is 22.3%, exactly what 445W over 1.99m² works out at. We corrected the catalogue entry to 22.3% on 21 September 2026, and fixed its model label, which read “455W” against a 445W rating. The panel tables in our sizing and cost guides were corrected with it.

The Jinko row has now been corrected too. Our catalogue had it at 445W/23.0% under a “485W” model label, three bins in one entry, and the current EU 48QL6 datasheet has no 445W bin at all: it runs 460–485W at 23.02–24.27%, and a 445W module at 1,762 × 1,134mm would be 22.3%. On 21 September 2026 we rebuilt the entry on a single bin, the bottom 460W/23.02% one, because that is the closest the datasheet gets to the 440–445W class the panels here are compared at, and corrected the panel tables in the sizing and cost guides to match. The Trina row (440W, 22.0%, 25-year product warranty) matches its datasheet exactly. Where our catalogue and a manufacturer’s dated document disagree, believe the document.

When the answer is no, and what to check first

When the roof has less than about 20 years left. This is the one that actually decides cases. A 25-year asset bolted to a covering that needs stripping in twelve years means paying twice to take the array off and put it back, and nobody prices that into a quote. Get the roof looked at before you get the panels quoted, not after.

When the warranty requires registration and nobody does it. Several manufacturers’ extended terms are conditional. Enphase’s “up to 25 years” on microinverters requires an internet-connected gateway, and panel warranties commonly require registration within a window after commissioning. Ask who registers it, get the confirmation in writing, and keep it with the MCS certificate. An unregistered 25-year warranty is a 0-year warranty.

When the product warranty is far shorter than the performance one. A 15-year product warranty against a 30-year power warranty, as on the Jinko, means that from year 16 the manufacturer guarantees the panel’s output but not the panel. In practice a power claim on a physically failed module is a much harder conversation than a defect claim. The gap is not a dealbreaker, and it is common enough that the panels are cheaper for it, but price it as what it is.

When the manufacturer’s UK presence is thin. A 25-year promise is only worth the entity that has to honour it in year 24, and a warranty is a claim against a company, not against a panel. This is not about any brand being unreliable; it is about whether there is a UK or EU entity, a claims process in English and a route that does not depend on a parent company’s decisions a decade from now. Ask who handles a warranty claim, where they are, and what happens if your installer has stopped trading. That last one is the common failure, not the panel.

When you cannot get the datasheet. JA Solar’s own .com site refused every request we made; we only got its numbers because its European site publishes the same PDFs, and even then the product-warranty term turned out to depend on the SKU. You are entitled to better: MCS 032:2025 clause 6.2.4(b) requires an MCS contractor to give you the “Manufacturer’s datasheet for the proposed solar modules” in writing before the contract is awarded; (c) is the inverter’s. Every figure in this guide came off one. Yours should too.

The ceilings, and what we could not read

Start at the solar hub if you are still deciding, or the panel listings if you are comparing specific modules.

One thing we did not manage to source. We wanted to set these warranted curves against a real-world field median. NREL’s compendium of photovoltaic degradation rates is the standard reference, and the usual figure quoted from that literature is around 0.5% a year. We could not reach nrel.gov from where we checked on 21 September 2026, so we are not going to quote a number we did not read. Take everything above as warranted ceilings, which is what they are: a real panel on a real roof usually does better than its warranty, but the warranty is the only part you can enforce.

All prices, rates and figures were checked on 21 September 2026. The price cap is reset quarterly and manufacturers revise datasheets without notice, so re-check both before committing.

What’s changed (changelog)

  • 21 September 2026 (fourth revision, same day). The JA Solar catalogue entry had the same mixed-bin fault we fixed on the Jinko row: the product page was showing 445W/22.8% and a 25-year product warranty from an old scrape of the 25Y SKU page, while our tables said 440W/22.5% and 15 years. It is now one bin everywhere, 440W at 22.0%, which is what the JAM54D40/LB datasheet prints for 440W, and the catalogue’s 15-year figure, explained above, is what the product page shows. The Trina product page had the same fault in miniature: an old scrape pinned 450W/22.5% while this table and the sizing and cost guides said 440W/22.0%. It now shows the 440W bin too.

  • 21 September 2026 (third revision, same day). Two rows that were flagged rather than answered are now answered. The Jinko catalogue entry was corrected to a single datasheet bin, 460W at 23.02%, 15-year product warranty, replacing an entry that carried a “485W” model label over a 445W/23.0% spec; the sizing and cost guides’ panel tables were corrected with it. And JA Solar’s European site, jasolar.eu, does serve the DeepBlue 4.0 Pro datasheets even though jasolar.com still returns HTTP 403, so that row now carries read figures: 30-year linear power, 1% first-year and 0.4%/yr degradation, 87.4% at year 30. Its product warranty is 12, 15 or 25 years depending on the SKU, so we have left our catalogue’s 15 in place and said why rather than picking one.

  • 21 September 2026 (revised same day). Read Aiko’s full Neostar 2S datasheet (V4.1, 202510) rather than just the product page it is linked from. It publishes the guaranteed output an earlier version of this page said was unavailable, 90.6% at year 25 and 88.85% at year 30, and it lists a 445W bin at 22.3%, which contradicted our catalogue’s 23.2% directly. We corrected the Aiko catalogue entry to 22.3% and its model label from “455W” to “445W”, and corrected the panel tables in our sizing and cost guides to match. The Jinko entry stayed flagged at this point, because its intended power bin was not clear from the datasheet; it was corrected later the same day.

  • 21 September 2026. First published, against the AIKO Neostar 2S datasheet, the JinkoSolar EU JKM460-485N-48QL6-DV datasheet and the Trina Vertex S+ TSM-NEG9R.28 datasheet, with inverter warranty figures carried over from our inverters guide and the 4,360kWh PVGIS example from our sizing guide. JA Solar’s site returned HTTP 406/403 to every request, so that row is unverified and labelled as such.

FAQs

How long do solar panels last?

Longer than the warranties, but the warranties are the only part anyone will honour. Of the four panels we compare here, Aiko and Trina carry 25-year product warranties, Jinko 15 years, and JA Solar's DeepBlue 4.0 Pro is sold in 12-, 15- and 25-year product-warranty variants of the same panel; all four carry 30-year performance warranties. On their own warranted degradation curves a panel is still producing 89.9–91.0% of its rated output in year 25, and the datasheets guarantee 88.85% at year 30 for the Aiko and the Jinko and 87.4% for the Trina and the JA Solar. Aiko's chart also marks 90.6% at year 25. Nothing in those documents says the panel stops at 25 or 30: that is where the promise stops, not the panel.

How much output do solar panels lose each year?

On the warranties we read: no more than 1% in the first year, then no more than 0.35% a year for the Aiko Neostar 2S and the Jinko Tiger Neo 3.0, and no more than 0.4% a year for the Trina Vertex S+ and the JA Solar DeepBlue 4.0 Pro. Those are warranted ceilings, not measured field rates. A real panel usually does better, but the ceiling is the number you can enforce.

Does a 25-year panel mean 25 years of no maintenance?

No, because the inverter almost certainly will not last that long. Growatt's SPH 3000-6000TL BL-UP datasheet states a 5-year warranty with 10 years optional; the Solis S6-EH1P datasheet we read carries no warranty row at all; Enphase claims up to 25 years on its UK IQ8 microinverters, conditional on an internet-connected IQ Gateway. A 25-year panel life spans at least one string-inverter warranty and probably several. There is no official UK figure for what a replacement inverter costs fitted, so we are not going to invent one.

What does 23% panel efficiency actually mean?

It is the fraction of the sunlight landing on the module that comes out as electricity under standard test conditions: 1,000W/m², 25°C cell temperature, AM1.5 spectrum. So 23% is 230W per square metre. It decides how many kW you fit on a fixed roof, not how long the panel lasts or how fast it fades: a 22.1% panel and a 23.6% panel on the same warranted curve lose output at the same rate, and on Aiko's datasheet those are the bottom and top bins of the same physical module.

Is a higher-efficiency panel worth paying for?

Only if your roof is the constraint. A current residential module is about 1,757 × 1,134mm, just under 2m². On Aiko's Neostar 2S datasheet that one physical panel is sold at 440W/22.1% at the bottom and 470W/23.6% at the top, so on a roof with room for ten panels the efficient bin buys you 300W, under 7% more capacity. If you have spare roof plane, buy the cheaper panel and fit one more.

Sources

  1. AIKO: NEOSTAR 2S54 Mono-Glass 440W-470W product page and datasheet · checked 21 Sept 2026
  2. AIKO: Neostar 2S AIKO-A-MAH54Mb 440-470W datasheet, V4.1 (202510) · checked 21 Sept 2026
  3. MCS: MCS 032:2025 Issue 1.0, Solar PV & Battery: Pre-Sale Information and System Performance Estimate Standard, 1 January 2025 · checked 21 Sept 2026
  4. JinkoSolar EU: JKM460-485N-48QL6-DV-F2-EU datasheet (Tiger Neo 3.0, mono-facial dual glass) · checked 21 Sept 2026
  5. JinkoSolar EU: Tiger Neo 3.0 (TOPCon) PV modules product page · checked 21 Sept 2026
  6. JA Solar Europe: JAM54D40 LB 15Y (DeepBlue 4.0 Pro) product page · checked 21 Sept 2026
  7. JA Solar: JAM54D40/LB DeepBlue 4.0 Pro datasheet, Global-EN-20240423A (linked from the JAM54D40 LB 15Y page) · checked 21 Sept 2026
  8. JA Solar: JAM54D40/LB 25-year product warranty datasheet · checked 21 Sept 2026
  9. Trina Solar: Vertex S+ TSM-NEG9R.28 datasheet, version TSM_EN_2023_B · checked 21 Sept 2026
  10. Growatt: SPH 3000-6000TL BL-UP datasheet (document dated 09/12/2025) · checked 21 Sept 2026
  11. Enphase: IQ8MC, IQ8AC and IQ8HC Microinverters data sheet, United Kingdom (DSH-00198-5.0-EN-2026-03-30) · checked 21 Sept 2026
  12. Ofgem: energy price cap unit rates, 1 Oct–31 Dec 2026 · checked 20 Sept 2026
  13. EC JRC: PVGIS · checked 20 Sept 2026

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