Spacia vs Fineo vs LandVac: the three vacuum glazing units compared
Ask three UK glazing firms to quote vacuum glass for a period window and you will almost certainly hear the same three names: Pilkington Spacia, AGC Fineo and LandVac. All three do the same fundamental job — two panes of glass separated by a sub-millimetre evacuated gap, held apart by a grid of tiny support pillars and closed with a hermetic edge seal, in roughly the thickness of a single pane. But they are not interchangeable. They differ in where they are made, how the edge is sealed, whether the glass is toughened, how well they insulate, how long you wait for them and how long the maker will stand behind them. This guide sets the three side by side on the terms that actually affect a UK buyer, then adds a short note on the newer entrants you may start to encounter.
What the three share, and where they part
Every product here is a vacuum insulated glazing (VIG) unit, and the underlying physics is identical. The cavity is pumped down to roughly 0.1 Pa — about a thousandth of atmospheric pressure — which removes almost all conduction and convection through the gap. That leaves radiation as the dominant heat path, so a low-emissivity coating on one internal surface does the remaining work. A grid of microscopic pillars stops the two panes from being crushed together by the roughly ten tonnes per square metre of atmospheric load bearing on them. For the principle in full, see the pillar and seal engineering on our main guide.
Where the products diverge is in four things that a homeowner or specifier can actually feel in the quote and in the finished window: the edge seal (which in turn decides whether the glass can be toughened), the centre-of-glass U-value, the appearance at the edge and across the pane, and the supply — lead time, warranty and availability in Britain. Those are the axes we compare below.
One standards note worth carrying into any conversation with a fabricator: the familiar sealed-unit standard EN 1279 explicitly excludes vacuum glass, so no VIG can be “EN 1279 certified.” Vacuum units are covered instead by ISO 19916 (Part 1 was published in 2018). If a supplier claims EN 1279 for a vacuum product, treat it as a red flag rather than a reassurance.
Pilkington Spacia — the original
Origin. Spacia is made by Nippon Sheet Glass (NSG) in Japan and sold worldwide under the Pilkington brand. It matters historically: launched in October 1997, it was the world’s first commercially viable VIG, built on the vacuum-glazing research done at the University of Sydney. Everything else on this page came later.
Seal and appearance. Spacia uses a rigid glass-frit (solder-glass) edge seal, fired around the perimeter in a furnace. That firing runs hot enough to anneal the glass, which is why classic Spacia panes are annealed rather than toughened — to count as safety glass they need an applied safety film or lamination. The seal route also leaves a visible pump-out port: a small round evacuation point with a protection cap, usually tucked into a corner. The support pillars sit on a roughly 20 mm grid — around 2,600 per square metre — visible as a faint regular pattern of dots on close inspection, unobtrusive at normal viewing distance.
Performance. The headline figure people most often get wrong: classic Spacia is about 1.1 W/m²K centre-of-glass, not 0.4. That is genuinely good — it matches a decent modern low-E argon double-glazed unit, but in single-glazing thickness — and it is the honest number to quote. (Pilkington’s wider-pillar-array Super Spacia reaches around 0.7, but that is a distinct product, not the standard Spacia unit.) At about 6.2 mm total, Spacia is the slimmest of the three, which is precisely why it drops into tight historic rebates. Acoustically it sits around Rw 35 dB.
Supply. Spacia carries the longest typical lead time of the three — on the order of 16 weeks — and its warranty is the shortest at around 10 years. It is a first-generation product, and UK fabricators now candidly describe it as surpassed on pure U-value by the tempered units. Its case rests on slimness and pedigree rather than record numbers.
AGC Fineo — the European flagship
Origin. Fineo is made by AGC Glass Europe at Lodelinsart in Belgium, with production beginning in March 2019 as a joint development with Panasonic. Being manufactured in Europe rather than shipped from Asia is a real advantage for UK supply; it reaches Britain through distributor Energlaze UK and is fitted nationwide by trade joiners.
Seal and appearance. This is where Fineo is distinctive. AGC does not publicly disclose its edge-seal chemistry — it is a proprietary low-temperature process, and it is neither accurate nor fair to call it “solder-glass.” The visible consequence is the important part: Fineo has no pump-out port at all, so there is no protection-cap button in the corner. What you get instead is a very slim edge seal, a slight double reflection and a small QR code mark. For buyers who dislike the look of a visible evacuation plug, that is the cleanest face of the three.
Performance. Standard Fineo delivers Ug 0.7 W/m²K at 7.7 mm — squarely in triple-glazing territory, at a third of the thickness. A Fineo Hybrid version, which substitutes the VIG into a sealed gas-filled unit, pushes down to 0.4–0.5 W/m²K, but that is a thick 22–34 mm insulated glass unit rather than a slim retrofit pane, so it belongs to a different use case. Sound reduction sits around 35 dB and light transmission near 80%.
Supply. Fineo was the first VIG to obtain CE marking and a third-party Environmental Product Declaration, and it holds several national technical approvals across Europe. Lead times are the shortest of the three at roughly 4–8 weeks, and the warranty is the longest at 20 years, against a claimed lifespan of 60-plus years. As always, treat that lifespan as a manufacturer claim rather than an independently proven figure — the warranty is the number that binds. A safety/laminated variant is available where toughened or laminated glass is required.
LandVac — the tempered challenger
Origin. LandVac is made by LandGlass in Luoyang, China, and reached market in March 2016 after roughly eight years of development. It represents the pivot to tempered VIG, and to the larger formats that made curtain-wall and passive-house use practical.
Seal and appearance. LandVac’s defining feature is a proprietary low-temperature seal — described by the maker as a flexible lead-free alloy — which crucially keeps the glass fully tempered. That is not a metal-welded seal in the V-Glass sense; it is a proprietary chemistry, and the practical result is what matters: LandVac meets safety-glass standards on its own, with no film or lamination needed. It has a visible pump-out plug like Spacia. Its stand-out visual advantage is a notably low pillar density — around 267 pillars per square metre, roughly a tenth of a classic 20 mm grid — so the dot pattern is much harder to see.
Performance. LandVac has the best insulation of the three: 0.4–0.48 W/m²K (manufacturer figures), deep into passive-house territory. It is also the thickest at 8.3 mm — still a fraction of a sealed double-glazed unit — and the heaviest, though tempering earns that thickness back as genuine safety glass. Acoustically it is the strongest, cited at around 36–39 dB depending on the exact build-up.
Supply. The trade-off is logistics. Lead times are the longest and least predictable — commonly 10–16 weeks with shipping from China (faster by airfreight, at a cost). The warranty is 15 years, with a design life the maker puts at 25-plus years.
The three compared
How to read this table. The U-values are Ug — centre-of-glass — so they compare like for like. Whole-window (Uw) figures, such as the roof-window numbers further down, are always higher and are not directly comparable. All prices, lead times and lifespans below are indicative market and manufacturer figures, not quotes or guarantees.
| Pilkington Spacia | AGC Fineo | LandVac | |
|---|---|---|---|
| Maker / country | NSG / Pilkington — Japan | AGC Glass Europe — Belgium | LandGlass — China |
| First to market | Oct 1997 (first commercial VIG) | 2019 | 2016 |
| Centre-of-glass Ug | ~1.1 W/m²K | 0.7 W/m²K (hybrid 0.4–0.5) | 0.4–0.48 W/m²K |
| Total thickness | ~6.2 mm (slimmest) | 7.7 mm | 8.3 mm |
| Glass / safety | Annealed — needs film or lamination for safety glass | Annealed; safety/laminated variant available | Fully tempered — safety glass as standard |
| Edge seal | Rigid glass-frit (solder-glass) | Proprietary, undisclosed | Proprietary low-temperature alloy |
| Edge appearance | Visible pump-out port + cap | No visible port (slim seal, QR mark) | Visible pump-out plug |
| Pillar grid | ~20 mm grid (~2,600/m²) | Near-invisible micro-pillars | Low density (~267/m²) |
| Acoustics (Rw) | ~35 dB | ~35 dB | ~36–39 dB |
| Lead time (UK) | ~16 weeks | ~4–8 weeks (shortest) | ~10–16 weeks |
| Warranty | ~10 years | 20 years | 15 years |
| Claimed lifespan | Manufacturer claim | 60+ years (claimed) | 25+ years (claimed) |
Two patterns fall out of the table. First, U-value and thickness move together: the best insulator, LandVac, is also the thickest, while the slimmest, Spacia, gives up the most on U-value. Second, the tempering question is really a seal question — only the low-temperature seals (LandVac, and the newcomers below) keep the glass toughened, because a hot glass-frit firing anneals it. Everything else about safety follows from that one fact.
Other makers worth knowing about
A few more products sit at the edges of the UK conversation — several from China’s fast-growing vacuum-glass industry, plus a British brand. None displaces the main three in the UK retrofit market yet, but a well-informed buyer should recognise them.
HaanGlas (vacuum-glass.com). A Chinese maker (Shandong HaanGlas) offering two lines: HaanGlas Basic — annealed or tempered with a glass-solder seal — and HaanGlas PRO — tempered with a low-temperature metal edge seal. Its headline figures are Ug 0.47–0.5 W/m²K from 6.3 mm, sizes up to 1600 × 3000 mm and a claimed 25-year-plus life; the PRO line is notable for having no evacuation port and a choice of pillar spacings.
LEADUS (leadustech.com). Another Chinese manufacturer — Hebi LEADUS, founded by a team from Hong Kong Polytechnic University — making fully tempered vacuum glass, hybrid VIG and, unusually, vacuum photovoltaic glass that builds a solar-generating layer into the unit. It is one of the few firms that supplies both finished VIG and the production lines to make it. Published U-value figures are limited, so treat it as an industrial supplier to watch rather than a spec-sheet you can compare line-for-line.
Guardian + VELUX Heritage roof windows. Guardian Glass and the VELUX Group partnered in 2024 to develop tempered VIG, and the first deployment is a Heritage roof window launching in the UK and Ireland in 2026. The quoted figures are Uw 1.0 W/m²K whole-window, and Uw 0.83 with 38 dB for a hybrid version that adds a third gas-filled pane. Note the metric carefully: these are whole-window Uw numbers and are not comparable to the centre-of-glass Ug figures in the table above. This is a finished roof window, not loose glass for a joiner to install in an existing sash.
PassivGlas (UK). One of the few British vacuum-glazing brands, PassivGlas supplies toughened units — its Linear and Ultimate lines, plus a ReGlaze retrofit option — from 6.15 mm, with U-values as low as 0.44 W/m²K, acoustic performance up to Rw 41 dB (UKAS-tested) and a 15-year warranty. For a UK buyer, a domestic supply chain and support are the main draw over the imported units.
V-Glass. A pre-commercial US start-up in Wisconsin, V-Glass is the clearest example of a room-temperature metal-welded edge seal — made by ultrasonic welding rather than the low-temperature soldering the Chinese tempered units use — and is aimed at very low cost. It is not yet on sale. You will find all of these listed on our manufacturers overview.
Which suits which situation
There is no single winner; the right choice depends on what constrains the job.
Tightest heritage sightlines. Where the rebate is shallow and the priority is keeping original frames and slim glazing bars, Spacia — at 6.2 mm the slimmest unit — remains the natural pick, with the deepest pedigree behind it. The caveat is safety glass: classic Spacia is annealed, so where toughened or laminated glass is required (doors, low-level or large panes) you will need an applied film or a laminated build-up. This retrofit-into-timber scenario is the dominant UK use case, covered in depth in our guide to vacuum glazing for sash windows.
Best possible insulation. If the driver is hitting a low U-value — a deep retrofit, a passive-standard target, or a client who simply wants the best number — LandVac at 0.4–0.48 W/m²K leads, and its full tempering means it is safety glass without any extra step. Accept the longer, less predictable lead time and the extra couple of millimetres of thickness.
The all-rounder and the fastest supply. For a strong 0.7 W/m²K, the cleanest edge appearance (no visible port), European manufacture, the shortest lead time and the longest warranty, Fineo is the pragmatic middle path, and often the easiest to actually get hold of in Britain. Its hybrid variant is available if you need to push toward 0.4 and can accept a thicker unit.
Safety glass is non-negotiable. Choose LandVac (tempered as standard) or a tempered/laminated variant of the others; do not specify classic annealed Spacia without a film or lamination plan.
Roof windows. For pitched-roof heritage work, the VELUX Heritage VIG range from 2026 is the product designed for the job — but as a complete window, not a glass swap.
On budget, the three sit fairly close: as a rule of thumb vacuum glazing runs at a two-to-four-times premium over standard double glazing (an indicative market estimate, not a quote), with the gap narrowing against triple glazing and against the alternative cost of replacing the frames entirely. The full picture, including installation, is set out in our cost guide, and whether the premium is justified for your situation is the subject of is vacuum glazing worth it.
The bottom line
Spacia, Fineo and LandVac are best understood as three points on a single trade-off, not as better-and-worse versions of one thing. Spacia trades ultimate U-value for the slimmest profile and the longest track record. LandVac trades thickness and lead time for the best insulation and true tempered safety glass. Fineo sits between them with a clean, port-free face, European supply and the strongest warranty. Match the product to the constraint that actually governs your window — sightline, U-value, safety, or availability — rather than to a single headline figure, and be wary of any quote that blurs a centre-of-glass Ug with a whole-window Uw, or that promises “EN 1279” on a vacuum unit. Get those distinctions right and all three are sound, standards-covered products; the only real mistake is choosing on the wrong axis.