The Complete Guide to Double Glazing in Australia

Double glazing is not new technology. In most of Europe, it has been the legal minimum since the 1980s. In Australia, aluminium single-glazing still dominates — a peculiarity driven more by inertia than engineering.

This guide explains what double glazing actually is, how it performs, and what to specify for your climate zone.

A double-glazed unit consists of two panes of glass separated by a sealed cavity filled with argon gas. The argon is denser than air and dramatically slows the rate of heat conduction. The edges are sealed with a warm-edge spacer bar — a low-conductivity polymer strip that prevents heat bridging around the glass perimeter.

For climate zones 6–7 (Melbourne, Canberra, Hobart), specify a minimum Ug value of 1.1 W/m²K with a low-E coating on surface 3. For climate zones 1–3 (tropical and subtropical), prioritise solar heat gain coefficient (SHGC) over U-value. Target SHGC below 0.35 with a solar-control low-E coating.