Aiko vs LONGi for a UK roof: Neostar 3 or Hi-MO X10?

Choose the Aiko Neostar 3 when roof space is the limit, and the LONGi Hi-MO X10 when it is not. Aiko is the more efficient panel, at 24.3 per cent for the 485 W and 24.1 per cent for the 535 W against 23.5 per cent for the LONGi 530 W, and the 485 W is the shortest of the three, which helps on a short or split roof. On a large, clear roof that efficiency gap is worth about 0.6 square metres on a 5 kWp array, and both are £1,000 per kWp installed, so the product warranty decides. Both carry the same 30 year output guarantee, and the product warranty is where they differ. We fit both, and this guide is written to be fair to both.

All figures at standard test conditions. Aiko from datasheets revision 202608 V1.1, read 29 October 2026; LONGi from the Hi-MO X10 datasheet (UK and Ireland revision NU V01 20250603) and signed Limited Warranty, as on our LONGi page. The same Aiko wattage comes in other series with different glass, weight, fire class and product warranty, shown in the warranty table below; your written quote names the exact code.

Which suits your roof, Aiko or LONGi?

• Short, split or busy roof: the Aiko 485 W. At 1762 mm it is 228 mm shorter than the LONGi, so two portrait rows need about 3.5 metres of rafter run against about 4.0 metres, before edge clearance.
• Roof space is the limit: either Aiko panel. They need about 4.1 square metres of panel per kW, against about 4.3 for the LONGi, worked out from the datasheet sizes.
• Large, clear, simple roof: the LONGi or the Aiko 535 W, which are close on size, weight and glass. Both are £1,000 per kWp installed, so the look and the product warranty decide it.
• Longest product warranty wanted: the Aiko all-black S series, at 25 or 30 years depending on the size, against 15 years on the signed LONGi warranty. The Aiko P series is 15 years.
• Roof with real shade: neither panel replaces a shading design. Both makers claim an advantage in partial shade, and the evidence is covered below.

How much roof does each panel need?

Module efficiency is the share of the sunlight landing on a panel's face that becomes electricity under standard test conditions, so a higher figure means more watts from each square metre. This is what it looks like with ten panels of each.

Arithmetic from the datasheet dimensions. Panel area only, before gaps, edge clearance, obstructions and the survey.

The efficiency gap between the Aiko 535 W and the LONGi, 24.1 against 23.5 per cent, works out at about 0.12 square metres per kW, or roughly 0.6 square metres on a 5 kWp array. That is real and it is small. It matters when a roof is a panel or two short, and not otherwise. On a tight roof the length of the panel matters more than its efficiency, which is why the 485 W stands out. Weight is the other practical difference: at 21.1 kg the single glass 485 W is the lighter panel to carry up a scaffold, while the two dual glass panels are within 1.4 kg of each other. Our guide to how many solar panels fit your roof shows how to count them.

Is the Aiko or LONGi warranty better?

The output guarantee is identical. Both promise at least 99 per cent of rated power in year one, a decline of no more than 0.35 per cent a year after that, and at least 88.85 per cent at year 30, for the front of the panel only. The product warranty, which covers the panel itself, is where the two differ, and with Aiko it varies by series rather than by wattage.

Aiko terms from its Residential Modules (v1.8) and Full-black Gen-3 Infinite Modules (v1.2) warranty documents and its product pages, read 29 October 2026. The extension is paid, and Aiko decides project by project whether to grant it.

Aiko's current documents give 30 years for the all-black 54-cell series at 480 W and above, although some UK trade pages still show 25. That is why your written quote names the exact model code and the warranty document, rather than quoting one number for the Aiko 485 W.

Read what each warranty pays for, not only how long it runs. Aiko's terms let it choose between repair, replacement and a refund of residual value, leave removal and refitting costs with the owner, and ask for claims in writing within 30 days of spotting a fault, with serial numbers. The warrantor is Zhejiang AIKO Solar Technology Co., Ltd. in China, and claims go through Aiko or its authorised distributors. Check the labour wording in whichever panel warranty is on your quote: our best solar panels guide explains why REC's, which covers labour, is the exception. A warranty that runs into the 2050s is also only as good as the company still standing behind it, which is true of both brands.

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Do Aiko or LONGi panels cope better with shade?

Both are back-contact designs, and both makers say their panels lose less power than TOPCon in partial shade. Every figure below is a maker's own test unless it says otherwise, and none of them measures one brand against the other.

• Aiko's own test: in a flash test by TÜV Nord that Aiko cites, with a single cell masked, an Aiko panel kept about 95 per cent of its power under light cover and about 70 per cent under full cover, against about 90 and about 40 per cent for the TOPCon panel beside it.
• LONGi's own figures: power loss under partial shade up to 70 per cent lower than a TOPCon panel, with hot-spot temperature down by as much as 28 per cent. These are the figures on our LONGi page, and they are LONGi's.
• The one independent test we found was run by a Brisbane electrical and solar firm, with nine Aiko 465 W panels on one string and nine Canadian Solar 465 W panels on another. Moderate shade and a third of a panel covered made no difference. Under a very small shadow the Canadian Solar side lost about 150 W against about 50 W for Aiko. Over several weeks Aiko averaged about 0.9 per cent ahead, or about 0.2 per cent once its positive power tolerance was allowed for. The firm concluded Aiko's shade claims are overstated. It is a single small test, and Aiko disputes it.

Each maker compares itself with a TOPCon reference of its own choosing, so the numbers cannot be set side by side, and we have not found an independent test that puts an Aiko panel next to a LONGi. Our reading is that a back-contact design may help with small, hard shadows such as a vent pipe or an aerial, as the one independent test suggests, and that none of it fixes a roof shaded for much of the day. That is solved in the design: see microinverters, optimisers and string inverters, and our back contact guide for the technology behind both claims.

What does an Aiko or LONGi system cost?

Both are £1,000 per kWp installed, so the price follows the size of the system, not the badge. Ten LONGi 530 W panels at 5.30 kWp are £5,300, ten Aiko 485 W panels at 4.85 kWp are £4,850 and ten Aiko 535 W panels at 5.35 kWp are £5,350, all installed before any battery and subject to survey. An Aiko quote names the exact model code and its warranty in writing. Per-panel prices you may see online are trade prices for the bare module, not an installed price. The number to compare between quotes is the installed price per kWp with the product warranty beside it. Our LONGi page has the calculator, and the Aiko page covers the series and model codes.

What about Jinko, JA Solar, REC and Trina?

Other firms may quote you panels from these four makers. The table sets their datasheet figures beside the two panels in this guide, using the numbers in our best solar panels guide.

Figures from manufacturer and UK distributor pages, read 27 and 28 August 2026 (Aiko and LONGi as above). Different wattage bins are compared, so treat the gaps as a guide. The datasheet for the exact model on your quote governs.

On these figures the two back-contact panels lead on efficiency by between 0.7 and 2.3 percentage points. REC is the standout on warranty, because ProTrust covers labour as well as the panel when the system is fitted by an REC-certified installation team. Jinko's Tiger Neo has a 15 year product warranty on the datasheet we cite, the same as the Aiko P series and the signed LONGi warranty, and JA Solar's output guarantee ends at 87.4 per cent against 88.85 for Aiko and LONGi. The full reading of each is in our best solar panels guide, and solar panel types explained covers the cell technologies.

How we would choose between them