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Vacuum Insulated Glass (VIG): The Complete Guide

Vacuum Insulated Glass (VIG) — also called vacuum glazing — is a sealed glazing unit made of two glass panes separated by a sub-atmospheric cavity, sealed at the perimeter by a hermetic edge seal, and held apart by an array of spacer pillars. Removing the gas that conducts and convects heat in a conventional insulated glass unit (IGU) is the physical reason VIG can deliver low thermal transmittance in a slim profile.

This guide covers what VIG is, how it works, the standards and assessment documents that apply to it, where it is and is not covered by existing IGU standards, and a buyer-verification checklist. Where a value or claim on this page is manufacturer-reported rather than standards-defined, the text says so.

Researched and edited by VIG Guide · Methodology: how VIG Guide classifies sources · Last updated

How VIG Guide handles technical claims

This page distinguishes between three classes of source so that readers can judge the basis of each statement:

Primary / independent
Standards bodies (ISO, CEN, ASTM), European Assessment Documents, peer-reviewed research, and independent laboratory test reports. Values and statements sourced from these are treated as the basis for any technical claim on this page.
Manufacturer-reported
Manufacturer datasheets, technical brochures, and product declarations. Where a specific value (for example a U-value, a maximum panel size, or a service-life target) is taken from such a document, the text labels it as manufacturer-reported.
Not yet independently verified by VIG Guide
Where VIG Guide has not personally reviewed the underlying test report or visited a manufacturing facility, claims relying on such evidence are labelled as manufacturer-reported and not as "VIG Guide verified".

VIG Guide does not currently run its own laboratory, has not visited every manufacturer's factory, and has not independently tested every product mentioned on this page. Where the editorial review status of a claim is unverified, the page says so.

What is Vacuum Insulated Glass?

Primary sourceThe European Assessment Document EAD 300021-00-0404 (EOTA, February 2019) defines a VIG unit as:

A glazing product consisting of two panes of glass, separated by an array of spacer pillars and sealed along the periphery, whereby the space between the glass panes is evacuated to a pressure below 1 Pa (10⁻² mbar).

The same EAD covers a related construction, laminated VIG (LVIG), in which one or both glass panes are laminated glass in accordance with EN 14449.

The terms vacuum insulating glass, vacuum insulated glass, and vacuum glazing are used interchangeably in the literature. Vacuum Glass also appears as a search term; ISO 19916-1 uses the form "vacuum insulating glass".

How does VIG reduce heat transfer?

Heat moves across a glazing cavity by conduction through the gas, convection within the gas, radiation between the cavity-facing surfaces, conduction through the spacer pillars, and conduction through the edge seal. VIG does not remove all five; it primarily removes the first two.

Conduction and convection in the cavity

Evacuating the cavity to a pressure below 1 Pa removes the gas as a meaningful medium for conduction and convection. Gas conduction scales with gas density; convection requires a gas of sufficient density to support bulk motion. Both are negligible in a hard vacuum at the pressures defined in EAD 300021-00-0404.

Radiation

Radiation between the two glass surfaces is independent of the cavity gas. A low-emissivity (low-e) coating on the cavity-facing surface of one pane is what suppresses this path; without a low-e coating, a VIG unit would lose substantially more heat by radiation than a typical insulated glass unit with low-e.

Solid conduction through pillars and edge seal

The spacer pillars and the hermetic edge seal remain solid heat-conducting paths. They occupy a small fraction of the cavity area, but their thermal contribution is not negligible: pillar geometry and edge-seal width both influence whole-window performance. EAD 300021-00-0404 requires that pillar spacing and edge-seal geometry be specified as part of the product definition.

Technical note — vacuum alone is not enough.A common simplification is that "VIG reduces heat transfer by removing the gas". This is misleading: a VIG unit without a low-e coating would still lose substantial heat by radiation; a VIG unit with too-widely-spaced or too-large pillars would lose additional heat by solid conduction. VIG performance is a result of all five paths being engineered together, not of the vacuum alone.

Main components of a VIG unit

The components below are common to every VIG construction described in EAD 300021-00-0404. Specific materials, dimensions, and counts vary by product.

  • Glass panes. Two float-glass plies. Some products use a laminated inner or outer ply (see annealed, toughened and laminated VIG).
  • Vacuum cavity. The space between the panes, evacuated to a pressure below 1 Pa.
  • Spacer pillars. An array of small elements that keep the panes from collapsing together under atmospheric load. EAD 300021-00-0404 lists the materials that may be used: glass, solder glass, ceramics, metal, or appropriately adapted synthetic materials. Pillar diameter, height, and pitch are manufacturer-specific and must be declared as part of the product specification.
  • Hermetic edge seal. EAD 300021-00-0404 describes this as a seal based on solder glass. The seal maintains the vacuum and resists shear, humidity, and temperature differentials.
  • Low-emissivity coating. A sputtered coating applied to one or both cavity-facing surfaces, reducing radiative heat transfer.
  • Getter. A substance inside the cavity that sorbs residual gas, helping the unit maintain sub-atmospheric pressure over time.
  • Evacuation port. The port through which the cavity is evacuated during manufacture; it is sealed as part of the edge seal.

Thickness and product geometry

Manufacturer-reportedTotal unit thickness, glass-ply thickness, cavity width, pillar dimensions, and edge-seal width are all product-specific and must be read from the relevant manufacturer datasheet. A common manufacturer-reported cavity width is around 0.1 mm; a common manufacturer-reported total thickness is in the region of 8 to 10 mm for non-laminated VIG. Both vary by product.

Independent standards (EAD 300021-00-0404, ISO 19916 series) define how these dimensions are measured and declared, not specific dimensional values for any product.

Thermal performance: Ug and Uw

The centre-of-glass U-value (Ug) is a property of the glazing alone, measured at the centre of the pane under a defined temperature differential, per EN 673 (calculation method) and ISO 10292 (calculation of steady-state U-values of multiple glazing). The whole-window U-value (Uw) additionally accounts for the frame, the edge-of-glass zone, and the spacer system. EAD 300021-00-0404 requires the ETA to state the U-value, truncated to three decimals.

Manufacturer-reportedManufacturer datasheets typically describe VIG with a single low-e coating as delivering centre-of-glass U-values in the region of 0.4 to 0.7 W/m²K. The actual figure for any specific product must be taken from that product's datasheet and test report, not from a generic range.

Why Ug and Uw should not be confused.Comparing a VIG Ug to a competitor's Uw is one of the most common specification errors in VIG procurement. Centre-of-glass and whole-window values are measured and declared differently; comparing them as if they were the same quantity overstates VIG's whole-window advantage.

VIG and double glazing

A double-pane insulated glass unit (DGUs / double glazing) and a VIG unit address the same problem — reducing heat transfer across a window — through different physics. A double-pane unit retains a 12 to 20 mm gas-filled cavity (typically air or argon) and reduces heat transfer via gas conduction, convection, and a low-e coating. A VIG unit replaces the gas with a hard vacuum in a much narrower cavity, eliminating gas-related losses while relying on the low-e coating for radiation and on careful pillar and edge-seal design for solid conduction.

Whether VIG or double glazing is the better specification depends on the project: rebate depth, weight, thermal target, listed-building status, budget, and lead time all matter. Compare declared centre-of-glass and whole-window U-values for the specific products being considered, not generic ranges.

See the VIG vs double glazing entry for a structured comparison.

VIG and triple glazing

A triple-pane insulated glass unit reaches a comparable centre-of-glass U-value band by adding a third pane and a second gas-filled cavity. The trade-off is profile depth and weight. VIG's principal advantage over triple glazing is in projects where the rebate cannot accept a triple-pane IGU — heritage windows being the most common case.

Like the comparison with double glazing, the right specification depends on the project. VIG does not in itself outperform triple glazing in every dimension; it wins where slim profile and weight matter, and where rebate depth is constrained.

See the VIG vs triple glazing entry for a structured comparison.

Annealed, toughened, and laminated VIG

VIG units may use annealed, heat-strengthened, or thermally toughened glass plies. The European Assessment Document EAD 300021-00-0404 explicitly references the European standards for these glass types (EN 12150-2 for thermally toughened safety glass, EN 1863-2 for heat-strengthened soda-lime silicate safety glass, EN 14449 for laminated glass).

Whether a particular VIG product is available in a toughened variant depends on the manufacturer. The thermal-toughening process is not compatible with every hermetic (solder-glass) edge-seal geometry, and not every manufacturer offers the option. Where safety-glazing codes require a particular classification, confirm with the manufacturer that the proposed variant carries the relevant third-party certification for the jurisdiction in question.

Laminated VIG (LVIG) — where one or both plies are laminated — is a separately-defined construction in EAD 300021-00-0404. LVIG combines the VIG thermal performance with the post-breakage retention of laminated glass, and is the subject of additional pendulum-impact testing in ISO 19916-4:2026.

Acoustic performance

Technical nuanceAcoustic performance of any glazing depends on glass thickness, interlayer presence, mass, decoupling between panes, and the installed frame — not on the cavity gas. The evacuated cavity of a VIG unit, by itself, does not deliver a specific sound-insulation figure.

Manufacturer-reported acoustic values (Rw, STC, or similar ratings) must be tied to a specific tested construction: glass thickness, interlayer, laminate presence, frame, and installation. A broad "VIG acoustic range" is not meaningful, because two VIG units with the same cavity construction can deliver different acoustic performance depending on the glass and interlayer choice.

For projects where acoustic performance is the primary driver, compare manufacturer acoustic test reports for the specific proposed construction, rather than generic VIG vs IGU comparisons.

Condensation

A low centre-of-glass U-value keeps the inner glass surface temperature closer to room temperature, which can reduce room-side surface condensation in cold conditions. Edge-of-glass performance — the dominant thermal bridge in VIG — depends on the edge-seal geometry and the frame design; condensation at the edge of the glass is therefore project-specific.

High-performance glazing can also exhibit external condensation under clear-sky radiative cooling: the outer surface drops below the external dew point and condensation forms on the outside. This is a sign of good thermal performance, not a failure. Where condensation is critical (museums, cold storage, refrigeration), confirm with the manufacturer and consider an independent hygrothermal analysis.

Durability, lifespan, and warranty

Primary sourceEAD 300021-00-0404 (§1.2.2 — Working life / Durability) explicitly states:

The indications given as to the working life of the construction product cannot be interpreted as a guarantee neither given by the product manufacturer or his representative nor by EOTA when drafting this EAD nor by the Technical Assessment Body issuing an ETA based on this EAD, but are regarded only as a means for expressing the expected economically reasonable working life of the product.

There is no single industry-wide service-life figure for VIG. Manufacturer warranties vary by product, by region, and by the terms of sale. Accelerated durability testing (such as the temperature-differential test methods in ISO 19916-3:2021) provides qualification evidence; it does not by itself demonstrate a specific field lifespan.

Three factors dominate long-term VIG performance:

  • Hermetic edge-seal integrity. Loss of vacuum through seal breach is the dominant failure mode described in the technical literature; once the cavity vents, the unit must be replaced.
  • Getter effectiveness. The getter sorbs residual gas and any slow leakage over time; its capacity is part of the product design.
  • Thermal cycling and mechanical load. Repeated temperature changes and applied loads can affect pillar bonds and edge-seal integrity; ISO 19916-3:2021 covers one test regime for these effects.
Warranty ≠ expected service life.A manufacturer warranty is a contractual term. An "expected service life" in an ETA is a design assumption, not a guarantee. The two are not interchangeable, and neither is a field-proven lifespan figure.

Failure modes

The technical literature describes several potential failure modes for VIG:

  • Edge-seal breach (loss of vacuum). Documented as the dominant failure mode. Once the hermetic seal is compromised, the cavity vents and the unit's thermal advantage is lost.
  • Mechanical impact failure. Independent peer-reviewed research (Schulz et al., 2022, Challenging Glass Conference Proceedings) found that VIG units failed at pendulum-impact drop heights below those prescribed by EN 12600, with pillar-to-glass contact identified as a fracture origin. ISO 19916-4:2026 now provides a VIG-specific pendulum-impact test method and classification.
  • Pillar-related defects. Pillar fatigue under thermal cycling, pillar detachment, and pillar-grid misalignment can cause localised cavity collapse or visual artefacts; these are addressed through manufacturer quality control rather than on-site mitigation.

Independent quantitative failure-rate data for VIG is limited. This page does not quote specific failure rates; any quoted percentage should be treated as a manufacturer claim unless it is tied to a published independent test report.

Main applications

VIG is commonly considered for projects where a conventional insulated glass unit cannot match the brief. Common application areas discussed in the technical literature include:

  • Heritage and listed-building windows with shallow rebates.
  • Vertical-sliding sash windows, where slim sightlines and reduced sash weight matter.
  • Steel and metal-framed heritage windows, where slim sightlines are part of the architectural value.
  • Slim-frame curtain walls and high-performance façades.
  • Refrigeration display doors, where slim profiles and low heat transfer matter.
  • Roof glazing and skylights where dead load is constrained.

See the Applications section for deeper entries.

VIG and heritage windows

The slim profile of VIG can make it a candidate for heritage retrofits. The principle: where a triple-pane insulated glass unit would not fit the existing rebate, a VIG unit may deliver a comparable thermal performance in the available depth, allowing the existing frame to be retained.

What VIG potentially offers in heritage retrofit

  • A slim profile that fits shallow rebates common in older frames.
  • Reduced sash weight compared with a triple-pane IGU of equivalent thermal performance.
  • Retention of original sightlines because the cavity is narrow and the plies are thin.
  • A glazing-only upgrade where the frame, ironmongery, and putty or bead can be retained.

What VIG does not do

  • VIG does not confer heritage approval. Whether a particular window can be upgraded with VIG — or any other glazing — depends on the local planning regime, the building's listing status, and the judgment of the responsible conservation officer.
  • VIG is not the only candidate. Slim triple-pane units, vacuum-plus-gas hybrid units, and other approaches exist; the choice should be made on the merits of the specific window and project.
  • VIG is not a guarantee of planning consent. Conservation officers assess each proposal individually. Treat VIG as a candidate option, not a substitute for the consent process.

Standards that apply to VIG

The standards landscape for VIG is fragmented and evolving. This section describes the current state of the ISO 19916 series, the European Assessment Document EAD 300021-00-0404, and how EN 1279 and ASTM E2190 relate to VIG.

ISO 19916 series — VIG-specific framework

ISO 19916-1:2018
Glass in building — Vacuum insulating glass — Part 1: Basic specification of products and evaluation methods for thermal and sound insulating performance.The first ISO standard dedicated to VIG. According to the ISO catalogue, this edition is in stage 90.92 ("International Standard under revision"). A revision is in progress as ISO/DIS 19916-1 (Draft International Standard stage, 40.20). The revised title in the catalogue broadens the scope from "thermal and sound insulating performance" to "performance" — signalling that the revision covers additional requirements beyond the original scope.
ISO 19916-3:2021
Glass in building — Vacuum insulating glass — Part 3: Test methods for evaluation of performance under temperature differences.Specifies test methods for evaluating VIG samples with a rigid edge seal under temperature differentials. Stage 60.60 (International Standard published).
ISO 19916-4:2026
Glass in building — Vacuum insulating glass — Part 4: Pendulum impact testing and classification.Specifies a method to evaluate, by means of impactors described in ISO 29584:2015, the safe-breakage characteristics of VIG products intended to reduce cutting and piercing injuries from accidental impact. Stage 60.60 (International Standard published).
Buyer note — Part 1 is being revised.If a manufacturer declaration references "ISO 19916-1", confirm whether the declaration refers to the 2018 edition or to the revised DIS version. The scope is changing.

EAD 300021-00-0404 — the European route

Primary sourceIn the absence of a harmonised European product standard for VIG, the European Organisation for Technical Assessment (EOTA) published EAD 300021-00-0404 (February 2019). This European Assessment Document specifies assessment methods for VIG units and laminated VIG (LVIG) units, and forms the basis on which a manufacturer obtains a European Technical Assessment (ETA) and Declaration of Performance.

The EAD covers, among other things: reaction-to-fire classification, pendulum body impact resistance (referencing EN 1279-5 clause 4.2.2.8 with adaptations), resistance against temperature differentials (Annex F), resistance against wind, snow, and imposed loads, direct airborne sound reduction, and the U-value (truncated to three decimals). Factory production control (FPC) and notified-body tasks are defined in Tables 3.2.1 and 3.3.1.

How VIG relates to EN 1279 and ASTM E2190

EN 1279 (the European insulating glass unit series) and ASTM E2190 (the North American insulating glass unit specification) are not VIG-specific standards. Their relationship to VIG is worth understanding carefully.

EN 1279

The scope of EN 1279-1:2018 (Insulating glass units — Part 1: Generalities, system description, rules for substitution, tolerances and visual quality) explicitly excludes vacuum insulating glass, with a note referring readers to ISO 19916. The EN 1279 series is built around the gas-filled cavity construction it defines — with edge sealants, spacers, desiccants, and cavity fillings — and these components do not exist in a VIG unit in the same form.

EAD 300021-00-0404 §1.2 states that VIG is not fully covered by EN 1279-5 "due to the explicit exclusion from the scope of the harmonised technical specification", and that several EN 1279-5 assessment methods (pendulum body impact, mechanical resistance, protection against noise, thermal properties, solar energy characteristics) "are not applicable without adaptation" to VIG. EN 1279-5 may nevertheless be referenced in specific VIG evaluation contexts — for example, for reaction-to-fire classification per EN 13501-1 — where its clauses can be applied with the adaptations described in the EAD.

ASTM E2190

ASTM E2190 (Standard Specification for Insulating Glass Unit Performance and Evaluation) covers preassembled, permanently sealed insulating glass units with one or two airspaces. Its scope is the conventional gas-filled IGU construction. Independent technical literature (e.g., NREL guidelines) describes ASTM E2188 as a test method that can be used to test specific physical properties of VIG specimens, but E2190 itself does not classify VIG as a covered product.

What this means in practice

  • Where a manufacturer claims "compliance with EN 1279-5" or "compliance with ASTM E2190" for a VIG product, the claim should be read alongside the EAD and ISO 19916 framework. EN 1279 / ASTM E2190 are not VIG-specific standards.
  • Where a VIG product carries an ETA based on EAD 300021-00-0404, the ETA is the VIG-specific evidence of assessment for the European market.
  • Where a VIG product is offered on the North American market, the relevant evidence base is the manufacturer's documentation and applicable regional standards — there is no single equivalent to EAD 300021-00-0404 in ASTM at present.

What buyers should verify

A practical checklist for buyers, architects, and glazing professionals specifying VIG. The list is designed to be worked through against the manufacturer's product documentation and any ETA or test report before committing to a procurement decision.

  1. Construction. Glass-ply thickness (each ply), interlayer presence and material, cavity width, pillar material and geometry, edge-seal material and width — exactly as declared by the manufacturer.
  2. Annealed, heat-strengthened, or toughened. Which outer plies are annealed, heat-strengthened, or thermally toughened; safety-glazing classification for the project jurisdiction.
  3. Declared Ug. Centre-of-glass U-value per EN 673 / ISO 10292, with the underlying test report number.
  4. Declared Uw. Whole-window U-value for the specific frame and edge-seal combination being specified — not a generic figure.
  5. Maximum panel size. Maximum width × height available for the project geometry, as declared by the manufacturer.
  6. Durability evidence. ISO 19916-3:2021 temperature-differential testing or equivalent; EAD 300021-00-0404 assessment if the product is on the European market.
  7. Pendulum-impact testing. ISO 19916-4:2026 classification if pendulum-impact performance is a project requirement, or evidence that the product has been tested to EN 12600 with the LVIG adaptations described in the EAD.
  8. Acoustic performance. Rw or STC rating from a recognised laboratory, with the report number and the specific construction tested.
  9. Independent laboratory. Name and accreditation of the testing laboratory (UKAS, A2LA, DAkkS, CNAS, or equivalent).
  10. Test report number and date. Current, traceable, and not historical.
  11. Applicable standards. The exact list of standards the unit is certified against, in the project jurisdiction.
  12. ETA / CE marking. For products on the European market: ETA reference, Declaration of Performance, AVCP system (per EAD 300021-00-0404 §3.1.1).
  13. Factory production control. Whether the manufacturer operates an audited FPC system (ISO 9001 or sector equivalent) consistent with the EAD §3.2 control plan.
  14. Warranty terms. Written terms, including what is covered (thermal performance, optical, edge-seal), what is excluded, and the term in years.
  15. Working-life indication. If the product documentation states a working life, read it in light of EAD 300021-00-0404 §1.2.2: an indication of working life "cannot be interpreted as a guarantee".

VIG brands and manufacturers (overview)

VIG Guide treats brand entries as research profiles, not rankings. Each brand profile page lists sourced figures with a verification date. This overview does not rank brands and does not assign a score; ranking and scoring methodology is in development (see Methodology).

The brands listed below each have a dedicated profile page on VIG Guide:

Brand-profile pages state whether each entry has been verified against manufacturer documentation, an independent test report, or neither. Where verification is partial or pending, the page says so.

See the Brands directory and the Manufacturers directory for the full list.

Advantages of VIG

Features that several commercial VIG products share, on the basis of manufacturer datasheets and the technical literature. Manufacturer-reported — verify for the specific product.

  • Slim construction. Lower profile depth than a triple-pane IGU at comparable centre-of-glass U-value.
  • Retrofit potential. May fit heritage rebates where conventional IGUs cannot.
  • Reduced sash weight. Lower weight than a comparable triple-pane IGU; relevant for sash windows and weight-sensitive roof glazing.
  • No gas fill to lose. No argon or other fill gas whose leakage would degrade performance over time.
  • Standards-backed assessment route. The ISO 19916 series and EAD 300021-00-0404 give a defined basis for assessing VIG performance for the European market.

Limitations of VIG

Limitations that several commercial VIG products share, on the basis of manufacturer datasheets, the technical literature, and the failure-mode research cited on this page. Manufacturer-reported or product-specific — verify for the specific product.

  • Edge-seal breach is a non-field-repairable failure. Once the hermetic seal fails, the cavity vents and the unit must be replaced as a whole.
  • Pendulum-impact behaviour is VIG-specific. Independent research has shown that VIG can fail at pendulum-impact drop heights below those prescribed by EN 12600 for monolithic glass; the ISO 19916-4:2026 classification should be checked for impact-rated applications.
  • Maximum panel size is product-specific. Some manufacturers cap panel size; oversize panels typically require longer lead times.
  • Toughened variants are not universally available. The thermal-toughening process is not compatible with every edge-seal design; some manufacturers offer laminated VIG (LVIG) as the safety-glazing alternative.
  • Cost varies by region, specification, and order size. This page does not quote cost figures; consult current manufacturer quotations for the specific configuration.
  • Working-life indications are not guarantees. Per EAD 300021-00-0404 §1.2.2.

FAQ

The most common questions about Vacuum Insulated Glass and vacuum glazing, answered briefly. The full structured-data version is in the page FAQPage schema.

Is Vacuum Insulated Glass covered by EN 1279?

No. The scope of EN 1279-1:2018 explicitly excludes vacuum insulating glass and refers readers to ISO 19916. EN 1279-5 may be referenced in specific VIG evaluation contexts, but several of its assessment methods are not directly applicable to VIG without adaptation.

Which ISO standard applies to Vacuum Insulated Glass?

The VIG-specific framework is the ISO 19916 series: ISO 19916-1:2018 (currently under revision, ISO/DIS 19916-1 in development), ISO 19916-3:2021 (temperature-differential testing), and ISO 19916-4:2026 (pendulum-impact testing and classification).

What is the European route to CE marking for VIG?

EAD 300021-00-0404. A manufacturer obtains an ETA against this EAD and draws up a Declaration of Performance.

How thick is a Vacuum Insulated Glass unit?

Varies by product. Manufacturer datasheets typically describe VIG units substantially thinner than a comparable triple-pane IGU. Read the specific figure from the relevant product datasheet.

Can vacuum insulated glass be toughened?

Depends on the manufacturer. Confirm with the specific manufacturer that the proposed safety-glazing variant carries the relevant third-party certification.

Is VIG suitable for heritage windows?

The slim profile makes VIG a candidate for heritage retrofits where a triple-pane IGU would not fit the existing rebate. Whether VIG is appropriate — and whether the proposal will receive any required planning or listed-building consent — depends on the specific window, the local planning regime, and the judgment of the responsible conservation officer.

Does Vacuum Insulated Glass contain visible pillars?

Yes — VIG units contain an array of spacer pillars. Whether these are visible from typical viewing distances depends on the pillar geometry and the lighting. Confirm against the specific product datasheet for premium-view projects.

Can vacuum insulated glass fail?

Yes. Documented failure modes include loss of vacuum through edge-seal breach and mechanical failure under impact. Independent quantitative failure-rate data is limited.

How long does a VIG unit last?

There is no single industry-wide service-life figure. EAD 300021-00-0404 explicitly states that working-life indications cannot be interpreted as a guarantee. Confirm declared service life and warranty terms against the specific product documentation.

What is the U-value of Vacuum Insulated Glass?

Manufacturer-reported centre-of-glass U-values for VIG with a single low-e coating typically sit in the region of 0.4 to 0.7 W/m²K, but the exact figure is product-specific. Compare declared Ug to declared Ug, and declared Uw to declared Uw, against the test report for the specific product.

Sources and citations

The following sources support this page. Where a statement is sourced to a standards body or a peer-reviewed publication, it is treated as primary. Where it is sourced to a manufacturer datasheet, it is treated as manufacturer-reported and is labelled as such in the body text.

Primary sources — standards and assessment documents

  • EAD 300021-00-0404 — Vacuum insulating glass units. European Organisation for Technical Assessment (EOTA), February 2019. Primary / independent source. Defines VIG and LVIG, references ISO 19916-1, EN 1279 (with adaptations), and EN 13501-1; specifies assessment methods including reaction-to-fire, pendulum body impact, temperature differentials, sound reduction, durability, and factory production control.
  • EN 1279-1:2018 — Glass in building — Insulating glass units — Part 1: Generalities, system description, rules for substitution, tolerances and visual quality. European Committee for Standardization (CEN). Primary / independent source. Its scope explicitly excludes vacuum insulating glass and refers readers to ISO 19916.
  • EN 673:2011 — Glass in building — Determination of thermal transmittance (U value) — Calculation method. CEN. Primary / independent source.
  • ISO 10292:1994 — Glass in building — Calculation of steady-state U values (thermal transmittance) of multiple glazing. ISO. Primary / independent source.
  • ISO 19916-1:2018 — Glass in building — Vacuum insulating glass — Part 1: Basic specification of products and evaluation methods for thermal and sound insulating performance. International Organization for Standardization. Stage 90.92 (under revision); ISO/DIS 19916-1 in development. Primary / independent source.
  • ISO 19916-3:2021 — Glass in building — Vacuum insulating glass — Part 3: Test methods for evaluation of performance under temperature differences. ISO. Stage 60.60. Primary / independent source.
  • ISO 19916-4:2026 — Glass in building — Vacuum insulating glass — Part 4: Pendulum impact testing and classification. ISO. Stage 60.60. References ISO 29584:2015 for the impactor. Primary / independent source.
  • ASTM E2190 — Standard Specification for Insulating Glass Unit Performance and Evaluation. ASTM International. Primary / independent source. Covers preassembled, permanently sealed insulating glass units with one or two airspaces; not a VIG-specific standard.

Primary sources — peer-reviewed research

  • Schulz, I., Kocer, C., Paschke, F., Schneider, J. (2022). The Performance of Vacuum Insulating Glazing Units Subjected to a Soft Body Impact. Challenging Glass Conference Proceedings, Volume 8. DOI 10.47982/cgc.8.443. Primary / independent source. Reports pendulum-impact testing of VIG units against EN 12600, finding failure at drop heights below the standard's prescriptive level, with pillar-to-glass contact identified as a fracture origin.
  • Dellieu, L., Šikyňová, A., Jeanfils, J. (2025). Vacuum Insulated Glazing: Innovations, Applications, and Overcoming Design and Legal Challenges. Glass Performance Days (GPD) 2025 Conference Proceedings, AGC Glass Europe. Primary / independent source. Reviews VIG product specifications, load calculations, and standards alignment.

Methodology references

  • VIG Guide Methodology — how VIG Guide classifies sources, separates manufacturer-reported claims from independently verified data, and updates pages when standards or product data change.
  • Editorial Policy — sourcing standards and correction procedure.
  • Commercial Disclosure — how sponsored and editorial content is separated on VIG Guide.

Manufacturer sources

Manufacturer datasheets are referenced on each brand profile page (Fineo, LandVac, Pilkington Spacia, Werkman) with a verification date attached. Where this pillar page cites a specific value, the body text marks it as manufacturer-reported.

Further reading