Clear glass with a microscopically thin metallic coating that reduces radiant heat transfer while keeping high daylight. Common in insulated glass units (IGUs) and some single-glazed setups.
Definition
Low-E coatings reflect long-wave infrared (heat) back to its source and can be tuned to admit or limit solar heat gain. In IGUs, pairing the coating with argon gas and warm-edge spacers further cuts conductive heat flow.
Why it matters
- U-value (Uw): Lower = better insulation.
- SHGC: Lower = less solar heat admitted (good for hot exposures); higher SHGC can aid passive winter gain.
- VLT: Aim for good daylight with acceptable reflectance for the façade look.
Coating types
- Soft-coat (sputter/MSD): Highest performance; must sit inside an IGU (typically surface #2 or #3).
- Hard-coat (pyrolytic): Tough, can be single-glazed (room side) or used within an IGU.
Positioning (surfaces)
Single-glazed: Put the coated face to the room side for protection.
IGUs: Most solar-control Low-E is placed on surface #2; some designs use #3 to favour winter gain.
Australia context
Low-E glazing is a common pathway to meeting NCC 2022 energy-efficiency targets (NatHERS/WERS ratings). Select products using certified AFRC/WERS data appropriate to your climate zone, orientation and shading.
Design notes
- Thermal stress: Consider toughened/heat-strengthened glass where assessments indicate risk.
- Care: Avoid abrasives on coated surfaces; follow supplier cleaning/handling guidelines.
- Appearance: Some coatings show slight haze or reflectivity in certain light—review samples on site.
Sources
- Guardian Glass — Low-E overview/how it works: guardianglass.com
- YourHome (AUS Gov) — Glazing, U-value & SHGC: yourhome.gov.au
- National Glass (AU) — Low-E design & glazing notes (surfaces, thermal stress, care): nationalglass.com.au (PDF)
- Viridian (AU) — EVantage™ (pyrolytic Low-E; installation/orientation): viridianglass.com
- Glassworks (AU) — Low-E coatings explained (soft vs hard, surface position): glassworksaust.com (PDF)
- ABCB/NCC — Energy efficiency guidance (NCC 2022): ncc.abcb.gov.au
Specification tip (AU): choose AFRC/WERS-rated IGUs with Low-E suited to your orientation and shading; detail frames for thermal breaks and seals.