Manufactured by Leadus Technology · Distributed in Canada by VIG Horizon Inc.
Vacuum insulated glass achieves what gas-filled IGU cannot: it eliminates convective heat transfer entirely. The result is a thin, single-unit panel delivering centre-of-glass performance comparable to triple glazing at 36–50 mm total thickness.
Heat moves through a window system via three mechanisms: conduction through the glass and spacers, convection through the gap fill, and radiation across the gap surfaces. In conventional gas-filled IGU, convection accounts for the majority of heat loss. VIG eliminates it entirely.
A single pane of glass is essentially transparent to heat. Conduction through the glass is high, convection on both interior and exterior air sides is uninhibited, and radiation passes freely with no Low-E coating.
Two panes with an argon-filled gap reduces convection compared to air but does not eliminate it. Argon has a thermal conductivity of 0.017 W/mK — better than air (0.026), but still conducting. Gas-fill degrades over time as argon slowly escapes through spacer seals.
Vacuum pressure below 10⁻² Pascal means there are essentially no gas molecules to carry heat. Convective transfer drops to zero. The only remaining pathways are conduction through the tiny ceramic pillar contact points, and radiation — which is dramatically reduced by the D80 double silver Low-E coating.
U-values are centre-of-glass unless noted. VIG U=0.40 per EN 673:2011 / NFRC 100-2010, confirmed by TÜV Rheinland (Report CN25TTIK, September 2025). Frame and edge effects excluded.
A vacuum insulated glass panel is a precisely engineered system, not simply "two panes with a vacuum between them." Each element — glass substrate, Low-E coating, ceramic pillar, metal seal, and getter — plays a critical and non-interchangeable role in the unit's lifetime performance.
Leadus uses fully tempered glass (minimum 90 MPa per quality standard). Glaston–Leadus cooperation announced February 2026. Must be tempered, not heat-strengthened — VIG operates under atmospheric differential pressure of ~10 tonnes/m², which fully tempered glass sustains without creep.
Applied to the inner face of the outer pane. Dramatically reduces radiative heat transfer across the vacuum gap. S1.16 single silver reduces emissivity to ≈0.04. D80 double silver reduces it further to ≈0.02 — the primary reason the 4+V+4 hits U=0.40.
A low-melting-point metal alloy seal runs around the full perimeter, hermetically joining the two panes. Unlike polymer or epoxy seals used in some competitors' products, metal seals are stable at extreme temperatures, do not outgas, and do not creep — rated to −35°C and 90°C.
The only structural elements within the vacuum gap. Typically cylindrical ceramic discs, 0.5mm (micro-dot) or 0.8mm (normal) in diameter, arranged in a precise grid. Each pillar supports atmospheric pressure load at its contact point. Spacing is configuration-dependent: 25–40mm depending on glass thickness. Ceramic has very low thermal conductivity, minimising pillar-path conduction.
A small chemical absorber embedded within the vacuum gap. Over the product's 15-year lifetime, trace gases can permeate through glass and the seal. The getter chemically binds these molecules, maintaining vacuum integrity without re-evacuation. Leadus uses a needle-type getter, which provides a larger reactive surface area than disc-type alternatives. No evacuation port — the unit is sealed without a visible port hole.
Ceramic pillar spacers are the most important performance variable within the vacuum gap. Their diameter, height, material, and grid spacing collectively determine the panel's structural integrity, optical quality, and residual conductive heat transfer. Leadus offers two pillar specifications across its product range.
The conventional ceramic spacer used in 3+V+3 configuration. At 0.8mm diameter, the pillar contact area is small but visible at certain angles under raking light. Used where cost efficiency and structural simplicity are the primary considerations — heritage slim-profile projects with tight tolerances.
The optional reduced-diameter spacer. At 0.5mm diameter, micro-dot pillars are less visible than the standard 0.8mm support at typical viewing distances. Reduced diameter also means lower per-pillar conductive heat transfer, slightly improving the overall U-value at equivalent grid spacing.
Why pillars are under enormous stress. Standard atmospheric pressure is 101,325 Pa ≈ 10.3 tonnes per m². A VIG panel with 0.2mm vacuum gap has the full atmospheric differential pressing the two panes together — a 1m² panel supports over 10 tonnes of compressive load through its ceramic pillars. Fully tempered glass (not annealed, not heat-strengthened) is the production prerequisite. Glaston–Leadus cooperation was announced in February 2026.
Conventional high-performance IGU fills the gap between panes with argon or krypton gas. These noble gases reduce convection compared to air. But they do not eliminate it — and their benefits degrade over time as gas slowly permeates through spacer seals. Vacuum is a fundamentally different approach.
Noble gas fill reduces convective heat transfer compared to air — argon conductivity is 0.017 W/mK vs 0.026 for air. But gas molecules still exist, still carry heat. Convection still occurs. And over 10–25 years, argon slowly permeates through the warm-edge spacer seal, being replaced by air.
Below 10⁻² Pascal, the mean free path of any remaining gas molecule is longer than the gap itself. Molecules cannot interact with each other to transfer heat. Convective heat transfer is physically impossible — not just reduced. And vacuum, unlike gas, cannot escape.
With convection eliminated by the vacuum, radiation becomes the dominant remaining heat transfer mode. Low-E coatings reduce this by reflecting long-wave infrared radiation — the thermal energy your heating system produces — back into the building. Leadus offers two Low-E specifications across its product range.
A single layer of silver deposited via magnetron sputtering between anti-reflection oxide layers. Provides a strong balance of low emissivity, high visible light transmission, and solar control — the practical standard for most heritage and residential applications.
Two silver layers with additional anti-reflection and barrier coatings. Reduces emissivity further than single silver while improving visible-to-solar selectivity — more daylight, less solar heat gain, better winter heat retention. The coating that enables Ug = 0.40 W/m²K in the 4+V+4 configuration, as calculated by TÜV Rheinland in Report CN25TTIK-002.
Glass flatness is the single most critical manufacturing variable in VIG production. The 0.2mm vacuum gap must be supported by ceramic pillars with sub-millimetre contact points. If the glass surface is not flat within tight tolerances, those contact points cannot support atmospheric pressure uniformly — and the vacuum seal fails. Glaston's FC500 tempering furnace delivers the world-standard for glass flatness. In February 2026, Glaston and Leadus formalised their cooperation to advance VIG manufacturing further.
Centre-of-glass values from Leadus Technology performance declarations. Where available, independent third-party calculation (TÜV Rheinland) is noted. For project-specific calculations, contact VIG Horizon Inc.
| Essential characteristic | 3TL+V+3T S1.16 · 6.2 mm |
4TL+V+4T D80 · 8.2 mm |
5TL+V+5T S1.16 · 10.2 mm |
6TL+V+6T S1.16 · 12.2 mm |
6TL+V+6T D80 · 12.2 mm |
|---|---|---|---|---|---|
| Visible light | |||||
| Visible light transmittance, Tv [%] | 80.4 % | 70 % | 80.4 %1 | 80.2 % | 69.5 % |
| Appearance and construction | |||||
| Sealing edge width — standard product [mm] | 10 mm | 10 mm | 10 mm | 10 mm | 10 mm |
| Pillar diameter — standard product [mm] | 0.8 mm | 0.8 mm | 0.8 mm | 0.8 mm | 0.8 mm |
| Sealing edge width — optional product [mm] | 6 mm | 6 mm | 6 mm | 6 mm | 6 mm |
| Pillar diameter — optional product [mm] | 0.5 mm | 0.5 mm | 0.5 mm | 0.5 mm | 0.5 mm |
| Thermal properties | |||||
| Thermal transmittance, Ug [W/(m²·K)] | 0.50 – 0.60 | 0.402 | 0.50 – 0.60 | 0.50 | 0.40 |
| Solar energy | |||||
| Solar heat gain coefficient, g (SHGC) | 0.56 | 0.42 | 0.561 | 0.573 | 0.375 |
| Shading coefficient, Sc = g/0.87 | 0.64 | 0.48 | 0.641 | 0.66 | 0.43 |
| Other data | |||||
| Nominal thickness [mm] | 6.2 mm | 8.2 mm | 10.2 mm | 12.2 mm | 12.2 mm |
| Nominal weight [kg/m²] | 16 kg/m² | 20 kg/m² | 24.8 kg/m² | 30 kg/m² | 30 kg/m² |
| Nominal weight [lb/ft²] | 3.28 lb/ft² | 4.10 lb/ft² | 5.08 lb/ft² | 6.14 lb/ft² | 6.14 lb/ft² |
| Vacuum pressure [Pa] | — | — | — | 1 × 10⁻³ Pa | 1 × 10⁻³ Pa |
| Maximum size [mm] | 1000 × 2000 | 1500 × 2500 | 1900 × 2800 | 1900 × 2800 | 1900 × 2800 |
| Maximum size [in] | 39.4 × 78.7 | 59.1 × 98.4 | 74.8 × 110.2 | 74.8 × 110.2 | 74.8 × 110.2 |
| Maximum area [m²] | 2.0 m² | 3.75 m² | 5.32 m² | 5.32 m² | 5.32 m² |
| Maximum area [ft²] | 21.5 ft² | 40.4 ft² | 57.3 ft² | 57.3 ft² | 57.3 ft² |
| Minimum size [mm] | 300 × 300 | 300 × 300 | 300 × 300 | 300 × 300 | 300 × 300 |
| Glass pane thickness | 3 mm each | 4 mm each | 5 mm each | 6 mm each | 6 mm each |
| Vacuum gap | 0.2 mm | 0.2 mm | 0.2 mm | 0.2 mm | 0.2 mm |
| Tempering degree | Fully tempered | Fully tempered | Fully tempered | Fully tempered | Fully tempered |
| Evacuation port | None | None | None | None | None |
| Getter type | Needle | Needle | Needle | Needle | Needle |
| Condensation | |||||
| Condensation risk (interior face) | Low — interior surface temperature stays above typical interior dew point | Very low — Ug 0.40 keeps interior face warm | Low | Low | Very low |
| Third-party documentation | |||||
| Independent U-value calculation | — | TÜV Rheinland CN25TTIK-002 | — | — | — |
| SGCC safety glazing cert. | #9744 (COMP)3 | #9744 (COMP)3 | #9744 (COMP)3 | #9744 (COMP)3 | #9744 (COMP)3 |
| IGCC seal durability cert. | #6076 (VG) | #6076 (VG) | #6076 (VG) | #6076 (VG) | #6076 (VG) |
| Aging / durability test | CTC WT2025E09A00265E (ΔU = 0.00) | CTC WT2025E09A00265E (ΔU = 0.00) | CTC WT2025E09A00265E (ΔU = 0.00) | CTC WT2025E09A00265E (ΔU = 0.00) | CTC WT2025E09A00265E (ΔU = 0.00) |
| Primary application | |||||
| Best fit | Heritage / slim-profile restoration | Net-zero / Passive House / most specified | Commercial / curtain wall | Structural / large formats | Structural / large formats · enhanced thermal |
Footnotes.
Values declared by Leadus Technology, centre of glass. Window-level U-value depends on frame and installation. Pillar diameter 0.8 mm standard with 0.5 mm optional. Where "—" is shown, data is not provided in the manufacturer declaration on file.
The China Testing & Certification International laboratory subjected sealed vacuum units to an accelerated aging protocol — thermal cycling, UV exposure, and sustained temperature extremes — then re-measured centre-of-glass U-value. The change: zero.
Metal-sealed vacuum does not degrade the way argon fill does. The getter continues to absorb trace permeating molecules. The pillar grid stays in place. The thermal credential measured on day one is still valid at year 15.
Certificates issued to Hebei Leadus Technology by CTC (China Testing & Certification International Group). PDFs are available on the Certifications page.
Download the full technical data sheet or request a project-specific specification package — U-value calculations, SGCC documentation, TÜV Rheinland thermal data. In English or French, within 48 hours.