The other two-thirds of the solution lie in profile and sealing

On the eve of drawing finalised drawings.

Flipping to the window section in the energyefficiency calculation report —

The overall window heattransfer coefficient is teetering right at the threshold.

Exterior wall insulation has been added layer upon layer, and the window to wall ratio has also been pushed down to the code-specified limit.

Yet the overall window U-value still falls just short of the target.

The familiar fix comes into play:

Switch to thicker glass? Add more insulating cavities?

There is some performance gain, but costs and self-weight surge sharply.

Meanwhile, thermal bridging in the frame profiles remains largely unaddressed.

Many projects stop here, settling for “good enough to pass inspection”.

But let us reframe the problem:

The overall window U-value is never a performance metric for glass alone.

I. Windows as a System: Three Interdependent Components

The bucketeffect applies perfectly to windows.

Even if glass is optimised to its physical limit, inadequate profiles will render all efforts futile.

If both glass and profiles perform well yet edge sealing permits excessive heat loss, the window still underperforms.

Two common pitfalls exist in conventional solutions:

Pitfall 1: Gas-filled insulating cavities are inherently heat-transfer media

Air (even when replaced with argon gas) still conducts heat and sound. There is a physical lower bound for the centreofglass heattransfer coefficient.

Pitfall 2: Aluminium profiles act as non-stop thermal bridges

Aluminium boasts a thermal conductivity of 237 W/(m·K), hundreds of times higher than composite thermalbreak profiles.

No matter how highperformance the glass is, heat keeps escaping outdoors through the metallic frame perimeter.

Performance ceilings encountered with singlecomponent upgrades stem essentially from neglecting the other two system components.

II. VIG® Solution: Optimise Glass, Profile and Sealing Simultaneously

① Glass: Vacuum instead of gas filling

A vacuum gap of approximately 0.5 mm is created between two glass panes. Combined with lowemissivity coatings and proprietary alloy vacuum sealing layers, fullperimeter welding is completed under vacuum conditions to form a longterm stable static vacuum system. Heat conduction loses its transfer medium at source.

② Profile: Glassfibrereinforced polyurethane composite thermalbreak profiles replacing aluminium

Key performance parameters:

表格

(The lower density is a hidden advantage for curtainwall projects sensitive to selfweight.)

③ Sealing: Labyrinthtype offset sealing

In conventional equalpressure sealing structures, heat travels along a straightline path at edges, causing prominent thermal bridging.

Labyrinthtype offset sealing greatly extends heattransfer pathways via structural dislocation. Performance is achieved not merely through material properties, but by forcing heat to take a “detour”.

III. Data Validation: Sealing Upgrade Delivers Higher EnergyEfficiency Ratings

For vacuuminsulated insulating composite glass with identical glass configurations:

表格

(Units: W/(m²·K))

Merely switching the sealing structure further lowers the overall Uvalue.

When glass and profiles are combined into full windows, the VIG® Series60 complete windows offer four standard configurations covering costeffective to ultralowenergyperformance requirements:

表格

(Units: W/(m²·K), test specimen: 1200 × 600 mm)

Look at the last row:

Fibrereinforced profiles paired with doublesilver lowe vacuum glass achieve an overall Uvalue of 0.89 W/(m²·K) — meeting window energyefficiency requirements for passivehouse and greenbuildingcertified projects.

Compared with the first configuration, the overall Uvalue differs by more than a factor of three.

For one identical window opening, different design schemes yield vastly different calculationreport outcomes.

IV. Corporate Credentials: Reliable ProjectScale Supply

For engineering contractors, advanced technology means little without assured supply and valid qualifications:

• Over 180 patents in total;
• Dual international environmental certifications: RoHS and REACH;
• One of the compiling organisations for Technical Specification for Application of Vacuum Glazing in Buildings (T/CECS 20902025).

Custom prototyping for individual projects is available, as is stable massscale delivery for largevolume developments.

V. Distinct Advantages in Special Climate Zones

Vacuum glazing paired with composite thermalbreak profiles excels in system windows, curtain walls, passive houses and sunrooms. Two project categories merit special attention:

Coastal highhumidity & highsalt regions

Conventional aluminium profiles tend to develop surface chalking and corrosion. Composite thermalbreak profiles deliver superior ageing resistance and weatherability, lowering longterm maintenance costs.

Highaltitude highpressure regions

Profiles face severe weathering challenges here, where composite materials demonstrate robust performance.

For building owners, this means compliance is not only achieved at handover, but thermal performance of the facade remains valid decades later.

VI. Submit Your Window Parameters — Close That Final Performance Gap

Reach out to the SuperVIG® technical team if you are working on:

• Passivehouse, greenbuilding or highperformance curtainwall projects comparing window system alternatives;
• Windowtowall schemes stuck at marginal energyefficiency compliance;
• Calculation of overall heattransfer coefficients for multiple configuration combinations.

Share your window dimensions and target energyefficiency grade. Our team can assist in calculating overall heattransfer coefficients for different setups, balancing performance and project cost.

Competition within the windowanddoor industry is shifting from isolated component specifications toward complete system solutions.

Passivehouse compliance opens only to systemoriented problemsolvers.

Predictable Uvalues stem from every carefully selected material layer. Successful inspections result from coherently interconnected system design.