LONGi solar panels
The panel that goes on most Newpower roofs, because it is the sensible middle of the market and it is genuinely black.
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Why people ask for LONGi by name
LONGi is the biggest panel manufacturer in the world by volume, and in this trade that matters more than it sounds. A company that size is still going to be there in year twelve when you want a warranty honoured, which is not something you can say about every badge that turns up on a price list.
The Hi-MO X10 uses back-contact cells, so like the Aiko there is no silver wiring across the front of the panel. You get a properly black roof rather than a black roof with a grid on it. The warranty is the part we point people at: 25 years on the panel itself and 30 on the output. Read those two numbers separately on any quote you get, because plenty of panels carry a long output warranty and a short one on the actual product.
It is the panel we reach for first, and not because it is the cheap option. Nothing else we fit carries 30 years on the output, and on a twenty-five year asset the company standing behind the paper matters as much as the specification printed on it. Where a roof is badly shaded we will talk you through the alternatives, but that is a minority of roofs and the survey will tell us.
- Back-contact cells, so no busbars across the front
- 25-year product warranty and 30-year performance warranty
- The largest panel manufacturer in the world, so the warranty means something
- MCS listed and zero-rated for VAT until 31 March 2027
We are a LONGi installer
The full LONGi range
We fit the whole LONGi range and will specify whichever module suits the roof, the budget and the space. The three below are how the range maps onto real jobs, not a list of the only ones we can get.
Roughly how the range maps onto real houses:
The standard roof
Most pitched roofs in South Yorkshire, on tile or slate.
- Cell type
- Back contact, no front-side wiring
- Appearance
- Full black
- Product warranty
- 25 years
- Performance warranty
- 30 years
Tight or awkward roofs
Where the roof is small and every watt has to count.
- Approach
- Higher output modules, fewer of them
- Trade-off
- More per panel, less scaffold time
- Worth it when
- The roof runs out before the demand does
- Alternative
- Aiko, if shade is the problem rather than space
Commercial roofs
Portal frame, flat and standing-seam roofs on business premises.
- Approach
- Volume modules, sized to the daytime load
- Mounting
- Ballasted or mechanically fixed
- Grid
- G99 application handled before anything goes up
- See also
- Our commercial solar page
How LONGi compares
| LONGi | Aiko | A standard mono panel | |
|---|---|---|---|
| Cell technology | Back contact | ABC back contact | PERC or TOPCon |
| Front-side wiring | None visible | None visible | Silver busbars |
| Partial shade | Handles it well | Handles it well | Loses a whole string to one shadow |
| Product warranty | 25 years | 25 years | Often only 12 |
| Performance warranty | 30 years | 25 years | 25 years |
| Behind the warranty | The largest manufacturer in the world | Established, newer to the UK | Varies, and that is the risk |
| Best for | The all-rounder, and what most roofs get | A roof that is heavily shaded or on show | A quote that is cheap for a reason |
The honest verdict
Why we fit a lot of them
- The longest warranty package we fit: 25 years on the panel and 30 on the output, which nothing else in the range matches
- Made by the largest panel manufacturer in the world, so there is a company left to honour it in year twenty
- Back-contact cells, so the roof is properly black with no silver lines across the front
- Enough output per panel that a small roof still gets a system worth having
What to weigh up
- No panel rescues a bad design. Orientation, pitch and shading decide what you get, and a good panel on a poor layout still disappoints
- Back-contact cells are newer than conventional ones, so nobody has twenty years of field data on them yet, whichever badge is on the front
- The panel is a smaller share of the price than the scaffold and the roof covering, so a quote that is cheap on panels is usually cheap somewhere that matters more
- If the roof runs out before your demand does, no amount of panel efficiency fixes it; that is a battery conversation, not a panel one
Questions we get asked about LONGi
Are LONGi panels any good?
They are the ones we fit most, and the warranty package is the best in our range: 25 years on the panel itself and 30 on the output, from the largest panel manufacturer in the world. When you are comparing quotes, that second number and the size of the company behind it are the two things worth checking.
LONGi or Aiko?
Both are back-contact panels with no wiring across the front, both are properly black and both carry 25 years on the product. LONGi has the longer performance warranty at 30 years and the bigger company behind it; Aiko has a small edge where a roof is heavily shaded. We specify from the survey, and on the great majority of roofs it is the LONGi.
What is the difference between the two warranties?
The product warranty covers the panel itself if it fails; the performance warranty guarantees a minimum output at a given year. LONGi give 25 and 30. Plenty of panels give 25 on output and only 12 on the product, which is the number that matters when one cracks.
Do I get 0% VAT?
Yes, on the whole installation, until 31 March 2027. After that it goes to 5%. On a job this size the deadline is worth real money.
How many will fit on my roof?
That comes from the survey, not from the square footage. Roof shape, obstructions, the position of the chimney and where the scaffold can stand all change the answer more than the total area does.
Get a price for a LONGi system.
We come and look at the house, tell you whether this is the right unit for it, and put the price in writing.