Can I have Low-E AND toughened in the same unit?

Yes, and this is very common. Low-E coating is applied first, then the glass is heat-treated to toughen it. The Low-E coating must be suitable for toughening (some soft coats are not). We handle this automatically when you specify both requirements.

Which glass is best for noise reduction?

Laminated glass provides the best acoustic performance due to the PVB interlayer absorbing sound vibrations. A sealed unit with one laminated pane and an asymmetric cavity (e.g. 6.4mm laminated / 16mm cavity / 4mm float) achieves significantly better noise reduction than standard symmetric units.

Is self-cleaning glass worth it?

Self-cleaning glass has a photocatalytic coating that breaks down organic dirt using UV light, which is then washed away by rain. It reduces cleaning frequency but doesn't eliminate it entirely. It's most worthwhile for hard-to-reach windows like roof lights or upper floors.

What's the difference between hard coat and soft coat Low-E?

Hard coat (pyrolytic) is applied during glass manufacture and is more durable but less thermally efficient. Soft coat (sputtered) is applied after manufacture and achieves lower U-values but must be protected within a sealed unit. Our standard is soft coat for best thermal performance.

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Technical Guide

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Glass Types Compared

Name: Pane Relief
Address: Bristol, Bristol, South West England, BS1, GB
Telephone: 0117 330 3057
Price range: ££
Rating: 4.3

From float glass to Low-E coated, toughened to laminated — a comprehensive comparison of glass types used in sealed glazing units.

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Expert Analysis

BS EN Standards

Specification Advice

Float Glass

Standard clear glass. Good optical clarity but minimal thermal performance. Used as the base for most other glass types. Rarely used alone in modern sealed units.

Low-E Coated Glass

Float glass with a microscopically thin metallic oxide coating that reflects heat back into the room. The standard for modern energy-efficient glazing. Our default specification.

Toughened Glass

Heat-treated for 4-5× the strength of float glass. Shatters into small granules when broken (safety glass). Required for doors, low-level glazing, and bathrooms.

Laminated Glass

Two glass panes bonded with a PVB interlayer. Holds together when broken, providing security and UV protection. Used for ground floor security and acoustic insulation.

Expert Knowledge

Choosing the Right Glass

The glass type you choose for your sealed unit affects thermal performance, safety, security, noise reduction, and UV protection. Most modern sealed units combine multiple glass technologies — for example, a Low-E coated outer pane with a toughened inner pane.

Float glass is the starting point for all other types. It's manufactured by floating molten glass on a bed of molten tin, producing perfectly flat, optically clear sheets. On its own, float glass has a centre-pane U-value of approximately 5.8 W/m²K — very poor by modern standards.

Low-E (Low Emissivity) glass transforms thermal performance. The coating — typically tin oxide (hard coat) or silver-based (soft coat) — reflects long-wave infrared radiation back into the room while allowing visible light to pass through. Soft coat Low-E achieves the best thermal performance and is our standard specification.

Toughened glass is a safety requirement, not a thermal upgrade. Building Regulations require toughened or laminated glass in specific locations: within 800mm of floor level, within 300mm of a door edge, in doors, overhead glazing, and bathrooms. We toughen glass to BS EN 12150.

Laminated glass uses a plastic interlayer (usually PVB) bonded between two glass sheets. It's the best choice for security, noise reduction, and UV protection. A 6.4mm laminated pane (3mm + 0.4mm PVB + 3mm) blocks 99% of UV radiation and provides significant noise reduction.

For most residential applications, we recommend soft-coat Low-E glass with argon fill as standard, toughened where required by Building Regulations, and laminated for ground floor security or noise-sensitive locations.

Yes, and this is very common. Low-E coating is applied first, then the glass is heat-treated to toughen it. The Low-E coating must be suitable for toughening (some soft coats are not). We handle this automatically when you specify both requirements.
Laminated glass provides the best acoustic performance due to the PVB interlayer absorbing sound vibrations. A sealed unit with one laminated pane and an asymmetric cavity (e.g. 6.4mm laminated / 16mm cavity / 4mm float) achieves significantly better noise reduction than standard symmetric units.
Self-cleaning glass has a photocatalytic coating that breaks down organic dirt using UV light, which is then washed away by rain. It reduces cleaning frequency but doesn't eliminate it entirely. It's most worthwhile for hard-to-reach windows like roof lights or upper floors.
Hard coat (pyrolytic) is applied during glass manufacture and is more durable but less thermally efficient. Soft coat (sputtered) is applied after manufacture and achieves lower U-values but must be protected within a sealed unit. Our standard is soft coat for best thermal performance.

Specify Your Glass Type

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