Insulated (IGU) Glass: Specification & Selection Guide

Specifying Insulated (IGU) Glass

An insulated glass unit (IGU) seals two or more panes around a spacer bar to trap a layer of air or gas between them. That trapped layer is what cuts heat flow and noise, which is why IGUs — often called double glazing — are the backbone of energy-efficient facades, curtain walls and skylights. This guide walks specifiers through the choices that matter: spacer width, size limits, standards and where IGUs fit.

How spacer width changes performance

The spacer bar sets the width of the sealed cavity, and that width drives thermal and acoustic behaviour. We offer a full range of spacer widths:

Spacer	Cavity width
6A	6 mm
9A	9 mm
12A	12 mm
16A	16 mm
20A	20 mm

Wider cavities generally improve thermal performance up to a point; acoustic tuning often uses asymmetric glass plus a chosen cavity. The right spacer is a balance of thermal target, acoustic target, unit weight and overall thickness — confirm it against your project’s performance brief.

Insulated glass specifications

Spec	Value
Single ply thickness	3–25 mm
Max size	3500 × 8000 mm
Spacer bar widths	6A / 9A / 12A / 16A / 20A
Standards	AS/NZS 4666:2012, EN 1279-1:2004 / -5:2005, GB/T 11944-2012

Because each glass ply can be specified independently, an IGU can combine flat tempered glass, laminated or coated glass to meet safety, security and solar-control goals in one unit.

Where IGUs fit

• Residential, office, mall and hotel facades — the standard energy-saving glazing.
• Daylighting roofs and skylights — thermal control overhead, usually with a laminated inner pane for safety.
• Energy-saving and acoustic settings — where heating/cooling load or noise must be reduced.

How to specify an IGU

1. State the performance target. Thermal, acoustic or both — this drives the spacer width and the glass make-up.
2. Set the glass make-up per pane. For example a coated outer pane for solar control and a laminated inner pane for overhead safety.
3. Check the size against the 3500 × 8000 mm limit and confirm unit weight for handling and framing.
4. Pick the spacer width (6A–20A) that balances your thermal and acoustic goals.
5. Name the standard (AS/NZS 4666, EN 1279, GB/T 11944) your project requires; our IGUs are produced to these.
6. Plan logistics — lead time 7–15 working days, MOQ 50 m², 10-year warranty, quoted EXW/FOB.

See the full insulated glass product page for build options, then send us your enquiry with your performance target, dimensions and quantity and we will quote EXW or FOB.

Sources

• Client product catalogue / knowledge base (insulated/IGU glass specs, spacer widths, standards and applications)
• Client knowledge base (lead time, MOQ, warranty, Incoterms)

Related reading

• Insulated glass (IGU) manufacturer — custom units