What is the lowest U-value your IGU can achieve?

A: For a standard Low-E insulating glass unit with argon fill, the typical U-value range is 1.2–1.8 W/m²K. This covers double-glazed units with double-silver or triple-silver Low-E coatings, a 12–20 mm cavity, warm-edge spacer and argon filling.

A U-value of approximately 0.7 W/m²K is achievable only with vacuum glass — and vacuum glass is limited to smaller panel sizes, so it is not suitable for most jumbo or full-height curtain-wall applications. Triple glazing with krypton/argon and warm-edge technology can also move the U-value downward, but the typical Low-E IGU you will specify remains in the 1.2–1.8 range.

The final U-value always depends on the complete IGU build-up: lite thickness, coating family, cavity width, gas fill, spacer type and frame. It must be confirmed by an IGU calculation per EN 673 / ISO 10292, not inferred from the coating datasheet alone.Related: IGU Selection Guide · Low-E Selection Guide

What is the difference between double-silver and triple-silver Low-E?

A: Double-silver is the workhorse for most commercial façades; triple-silver adds a third silver layer for lower solar heat gain at a similar visible transmittance.

• Double silver: balanced daylight + solar control, SHGC typically ≈ 0.28–0.35, VLT ≈ 55–65%. The default choice for office towers and curtain walls.
• Triple silver: lower SHGC ≈ 0.18–0.25 while holding VLT ≈ 50–60%. Used where aggressive cooling-load targets or selective daylighting justify the premium.

Neither coating choice alone determines the U-value — that comes from the full IGU system (cavity, gas, spacer). Specify the performance target first, then choose the coating family.Related: Low-E Selection Guide

Can you make vacuum glass in jumbo sizes?

A: No — vacuum glass reaches the lowest U-values (around 0.7 W/m²K) but cannot be made in jumbo formats.

Vacuum glass is a specialised product with strict size limitations, so it is generally used for smaller, high-performance elements rather than large curtain-wall panels. For oversize applications, a triple-silver Low-E IGU (U ≈ 1.2–1.4) is the practical high-performance route.Related: IGU Selection Guide

On which surface is the Low-E coating applied?

A: In a standard double-glazed IGU, the functional Low-E coating is normally on surface #2 — the interior face of the outer lite, counting from the outside in. This places the coating inside the sealed cavity, protecting it from weathering and abrasion.

Surface numbering: #1 = exterior-most, #2 = inner face of outer lite (default), #3 = outer face of inner lite, #4 = interior-most. Some solar-control or laminated systems use surface #3 — always record the surface number in the RFQ and shop drawings to avoid rejects.Related: Low-E Selection Guide

What SHGC and VLT can I expect from your Low-E glass?

A: SHGC typically ranges from 0.15–0.5, depending on coating family and make-up. Lower SHGC means less solar heat gain; balance it against the visible light transmittance (VLT) you need for useful daylight.

For example, a common double-silver IGU (6LowE + 16Ar + 6) delivers SHGC ≈ 0.28–0.35 with VLT ≈ 55–65%. Triple-silver holds VLT ≈ 50–60% while pushing SHGC down to ≈ 0.18–0.25. Exact values require an IGU calculation and confirmation against your energy code and orientation.Related: Low-E Selection Guide