Viridian Solar Panels Review (2026): The UK’s Best In-Roof System?
Viridian doesn’t make ordinary solar panels — it makes the Clearline Fusion in-roof system that sits flush with your tiles. Here’s our honest verdict on how it looks, how it performs, what it costs versus normal panels, and exactly who should (and shouldn’t) buy it.
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Who are Viridian Solar?
Viridian Solar is a British company, founded in 2004 by Stuart Elmes and based in Papworth, just outside Cambridge. It has spent two decades on one thing: roof-integrated solar that looks like part of the building rather than something bolted onto it. That focus paid off — Clearline Fusion became the go-to in-roof system for UK housebuilders, and in 2021 roofing giant Marley bought the company. Marley was then acquired by Marshalls plc in 2022, so Viridian now sits inside one of the UK’s largest building-materials groups, which matters for the long-term warranty and supply of a product you’ll have in your roof for 25 years. The same panels are also sold to housebuilders under the Marley SolarTile name.
Viridian also supplies its own Clearline Configurator — the design tool installers use to lay out panels and flashing on your roof — plus a Clearline inverter and the ArcBox connector enclosure. If you’ve been searching for the “Viridian configurator”, that’s an installer tool rather than something you’d use yourself; your installer will run it as part of your quote.
How in-roof solar works
With normal on-roof solar, aluminium rails are fixed to the rafters through the tiles and the panels sit 10cm or so above the roof. With Viridian’s in-roof system, the installer strips the tiles from the array area, fits a lightweight tray-and-flashing kit to the battens, and drops the panels in so they sit flush with the surrounding tiles. Special flashings at the top, sides and bottom lap under and over the tiles to keep the roof weathertight. The panels become the roof covering.
Three consequences follow. It looks far neater — no visible gap, no rails, no brackets. It works on almost any pitched roof covering: plain tiles, interlocking tiles and slate. And because the panels replace tiles, on a new build or re-roof you save the cost of the tiles you’d otherwise have bought. For the wider background on the pros and cons of the approach, see our guide to integrated solar panels.
Building, re-roofing or in a conservation area?
In-roof solar usually makes the most sense in exactly those cases — get it priced properly.
Get My In-Roof Solar Price →The Clearline Fusion range
| Model | Power | Efficiency | Notes |
|---|---|---|---|
| Clearline Fusion PV16 | ~400–405W | ~21.5% | Standard residential panel, all-black, 1722 × 1134mm |
| Clearline Fusion PV30 | ~480W+ | ~21% | Larger format for bigger roofs and commercial |
The PV16 is the one that goes on most homes: a full-size, all-black monocrystalline panel of around 400W, so a typical 4kW system is 10 panels. Earlier PV16 units used PERC cells; Viridian has been moving the range to newer N-type cells, so check the exact datasheet your installer quotes. Either way, these are conventional full-size panels rather than small “solar tiles” — that’s why Viridian delivers proper on-roof-level output while still looking integrated (see mono vs poly for why every panel here is monocrystalline).
Our scores
Our rating
Viridian Clearline Fusion
★★★★ The UK’s benchmark in-roof system
The bottom line: the best-looking, best-certified in-roof system in the UK. Outstanding value when it replaces tiles; a premium on a plain retrofit. The 10-year product warranty is the weak point.
Get my in-roof price →Performance & output
At around 21.5% efficiency the PV16 is a solid mid-range panel — a step behind the 22.5–24% of premium on-roof panels like REC or Aiko, but comfortably ahead of anything you’d get from a true solar tile. The bigger performance question with any in-roof system isn’t the cell, it’s the heat: panels set into the roof have less air moving behind them, run a few degrees warmer, and so produce a little less. Real-world figures are typically 2–5% lower annual output than the same panels on rails. Viridian’s tray design allows some ventilation to limit this, and in practice most installers simply add a panel on larger arrays to compensate. For what efficiency figures actually mean for your bills, see our solar panel efficiency guide.
Warranty & certifications
| Cover / approval | Viridian Clearline Fusion |
|---|---|
| Product warranty (panel) | 10 years |
| Performance warranty | 25 years (linear) |
| BBA certification | Yes — independently tested roofing system |
| MCS 012 | Yes — weathertightness, wind uplift & fire for roof-integrated PV |
| Fire rating | Broof(t4) — highest external roof rating |
The certifications are where Viridian shines. In-roof solar is part of your roof, so the questions that matter are “will it leak?” and “will it burn?” — and Clearline Fusion is BBA-certified as a roofing system, MCS 012 approved and Broof(t4) fire-rated, which is as good as it gets and why housebuilders and building-control officers are comfortable with it. The honest weak point is the 10-year product warranty. Mainstream on-roof panels now routinely offer 15, 25 or even 30 years on the product; 10 is thin by comparison. That’s partly offset by the 25-year performance guarantee and the Marshalls backing, but it’s the single biggest thing to weigh. As with any solar, the installer’s workmanship guarantee matters just as much — see how to choose a solar installer.
Price vs on-roof panels
| System (fitted, 0% VAT) | Viridian in-roof | Standard on-roof |
|---|---|---|
| 3kW | £6,600 – £8,700 | £5,000 – £6,500 |
| 4kW | £7,600 – £10,600 | £6,000 – £7,500 |
| Premium | Roughly 15–25% more for in-roof on an existing roof | |
The premium comes from the flashing kit, the extra labour of stripping and re-laying tiles around the array, and the installer needing roofing skills as well as electrical ones. But the maths flips completely in two situations. On a new build or a re-roof, the panels replace tiles you’d be buying anyway and the scaffolding is already up — so the true extra cost of going in-roof is often close to zero. That’s why nearly every new housing estate now uses in-roof solar. For the full picture see our cost of solar panels guide and the grants available in 2026.
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Get My In-Roof Solar Price →Who it suits (and who it doesn’t)
Viridian is the right call if…
- You’re building a new home or extension
- You’re re-roofing in the next year or two
- You’re in a conservation area or the planners want low-profile solar
- You have a listed building where in-roof may be the only acceptable option
- Looks genuinely matter to you — front-facing roof, high-value home
- You want the confidence of a BBA-certified, fire-rated roofing system
Look elsewhere if…
- You’re retrofitting a sound existing roof and want the best cost per kWh
- You want the longest product warranty available
- You need maximum output from a small roof (premium on-roof panels are more efficient)
- Your roof is flat or very shallow — in-roof needs a proper pitch
Viridian vs solar tiles vs on-roof panels
| Viridian in-roof | Solar tiles | On-roof panels | |
|---|---|---|---|
| Looks | Flush, integrated | Closest to a normal roof | Visible rails & gap |
| Output per kW | ~2–5% below on-roof | Lower efficiency | Highest |
| Cost per kW | +15–25% vs on-roof (≈ same on new build) | 2–3× on-roof | Lowest |
| Best for | New build, re-roof, conservation | Heritage / high-end aesthetics | Existing roof retrofit |
Viridian sits in the sweet spot between the two extremes. It gives you most of the visual benefit of solar tiles at a fraction of the cost, with full-size-panel output that tiles can’t match. Against on-roof panels it’s a straight trade: better looks and roofing-grade certification versus a modest cost premium, slightly lower output and a shorter product warranty. Which side of that trade you land on depends almost entirely on whether you’re already paying for a roof.
Pros & cons
Pros
- The neatest-looking full-size solar you can buy
- BBA-certified, MCS 012 approved, Broof(t4) fire-rated
- Near-zero extra cost on new builds and re-roofs
- Works on plain tile, interlocking tile and slate
- British company, 20-year track record, Marshalls-backed
- Often the only solar planners will accept in sensitive areas
Cons
- 15–25% dearer than on-roof on an existing roof
- 10-year product warranty is short by today’s standards
- 2–5% lower output than the same panels on rails
- 21.5% efficiency trails premium on-roof panels
- Needs an installer with roofing as well as electrical skills
Our verdict
4.3 / 5 — the UK’s benchmark in-roof solar, and the right answer for anyone already paying for a roof. If you’re building, re-roofing or in a conservation area, Viridian’s Clearline Fusion is genuinely hard to beat: it looks like part of the house, it’s certified to a standard no on-roof kit needs to meet, and the cost premium largely vanishes when it’s replacing tiles. That’s why the housebuilders use it.
On an ordinary retrofit the case is weaker. You’ll pay 15–25% more, get slightly less output and a shorter product warranty than a good on-roof panel — so unless looks are a priority, conventional panels are the better-value choice. Know which of those two homes you are, and the decision makes itself.
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Viridian solar panels: frequently asked questions
Are Viridian solar panels any good?
Yes — Viridian’s Clearline Fusion is the UK’s leading in-roof (integrated) solar system, and the one most installers reach for on new builds and re-roofs. The panels sit flush with the roofline in place of tiles, they’re BBA-certified and MCS 012 approved for weathertightness, and the finished look is far neater than on-roof panels. The caveats are cost — around 15–25% more than an equivalent on-roof system unless you’re re-roofing anyway — and a 10-year product warranty that’s shorter than most on-roof panels offer.
Who owns Viridian Solar and where are they based?
Viridian Solar was founded in 2004 by Stuart Elmes and is based in Papworth, near Cambridge. It was bought by roofing manufacturer Marley in 2021, and Marley was in turn acquired by Marshalls plc in 2022 — so Viridian is now part of the Marshalls group, one of the UK’s largest building-products companies. Its panels are also sold under the Marley SolarTile name.
How much do Viridian in-roof solar panels cost?
Expect roughly £7,600–£10,600 for a 4kW Clearline Fusion in-roof system fitted, against around £6,000–£7,000 for the same size on-roof — a premium of about 15–25%. On a new build or a re-roof the gap largely disappears, because the panels replace tiles you’d otherwise be paying for. On a straightforward retrofit to an existing roof, in-roof is the more expensive option.
Do in-roof solar panels produce less than on-roof panels?
Slightly. In-roof panels have less airflow behind them, so they run a little warmer and typically produce around 2–5% less over a year than the same panels mounted on rails above the tiles. For most homeowners that’s a small price for the look; on a large system the installer will simply spec an extra panel to compensate.
What is the Viridian warranty?
The Clearline Fusion panels carry a 10-year product warranty and a 25-year linear performance warranty. The 10-year product cover is shorter than the 15–25 years many mainstream on-roof panels now offer, which is the main thing to weigh against the aesthetic and weathertightness benefits.
Viridian vs solar tiles vs on-roof panels — which should I choose?
For a new build, a re-roof, a conservation area or anywhere looks matter, Viridian in-roof is the sweet spot: near-tile aesthetics at a fraction of the cost of true solar tiles, with full-size panel output. Solar tiles look the most like a normal roof but cost two to three times more per kW. For an existing roof where cost per kWh is the priority, ordinary on-roof panels remain the best value.
Figures are typical 2026 UK estimates for guidance only; panel models, wattages, warranty terms and prices vary by exact product version and installer — confirm on your quote and datasheet. Always use an MCS-certified installer. 0% VAT on solar applies until 31 March 2027 per HMRC. Sources: Viridian Solar specifications and UK installer pricing.