Low-E glass (low-emissivity glass) is float glass with a microscopically thin metallic coating that reflects long-wave heat (infrared) without significantly blocking visible light. It is the single biggest thermal upgrade you can apply to a window after double glazing.
How low-E coatings work
Heat radiates between surfaces in the infrared part of the spectrum. A bare glass pane absorbs and re-radiates that infrared, so heat flows easily through it. A low-E coating reflects the infrared back at its source, back into the room in winter, back outside in summer, while letting visible light pass through.
Two main types
| Type | How it is applied | Where it goes |
|---|---|---|
| Pyrolytic (hard coat) | Sprayed onto hot glass during float production | Single-pane windows; exposed surfaces; toughened use |
| Sputter (soft coat) | Magnetron sputtering of metal layers under vacuum | Inside the cavity of an IGU only (sensitive to moisture) |
What you get from low-E
- Lower U-value, typical IGU drops from 2.7 to 1.6 W/m²K with one low-E surface.
- Solar control, newer “selective” low-E coatings cut summer solar gain by 30 to 60% while preserving daylight.
- Less furniture and floor fade, UV transmission also drops slightly.
- Same daylight, visible light transmission is largely preserved.
How to identify low-E glass
Hold a lit match or flame near the pane. You will see four reflections from a standard double-glazed unit. If one of the reflections has a slight colour tint (often pinkish or amber), that surface has a low-E coating.
When to specify low-E
- Any new IGU, the cost premium is small relative to the long-term energy saving.
- North-facing rooms with summer overheating
- South-facing rooms losing winter heat
- NSW BASIX-driven new builds, low-E often makes compliance achievable
Frequently asked questions
Does low-E glass look different?
Very slightly. Some products have a faint tint or reflectivity; selective coatings are almost invisible. Talk to your glazier about samples before specifying.
Can low-E coatings degrade?
Sputter-coated (soft-coat) low-E will degrade if exposed to air or moisture, so it lives inside the sealed IGU cavity. Pyrolytic (hard-coat) low-E is durable and used in single-pane applications.
Is low-E the same as solar control glass?
Not exactly. All low-E reduces heat loss; “solar control” or “selective” low-E specifically reduces incoming solar heat too. Specify based on climate, winter-dominated rooms vs summer-overheated rooms.
Do I need low-E in a Penrith climate?
Yes, for new builds and any major renovation. Penrith has cold winter nights and hot summer afternoons, both directions benefit from low-E.
Get a quote
Need a quote? Call 02 4722 2787 or email sales@pantherglass.com.au with photos and we will come back the same business day.