How Glass Coatings Improve Energy Efficiency and Sun Protection

Energy Efficiency · 2025

Read time: ~7 mins · Updated: 16 Oct 2025

Modern glass is more than just a transparent barrier — it’s a high-performance material that can cut energy use, reduce glare, and protect interiors from damaging UV rays.
Thanks to advanced glass coatings, today’s windows can reflect heat, improve comfort, and even lower energy bills.
This guide explains how glass coatings work, the different types available, and how they can enhance both energy efficiency and sun protection in UK homes.

How glass coatings work

Glass coatings are microscopic layers of metal oxides or ceramic compounds applied during or after manufacture.
They modify the way glass interacts with light and heat — either reflecting infrared energy (to retain warmth) or blocking solar radiation (to stay cool).
According to the Energy Saving Trust, well-designed coatings can drastically improve window performance compared with uncoated glass.

Main types of glass coatings

• Low-E (Low-Emissivity) Coatings: Reflect heat back into the room while letting visible light through.
  Learn more at Guardian Glass – Low-E Overview.
• Solar-Control Coatings: Limit heat and glare from sunlight — ideal for south-facing façades or conservatories.
  See Saint-Gobain COOL-LITE® Solar Control Glass.
• Self-Cleaning Coatings: Use UV light to break down dirt, allowing rain to wash it away naturally.
  Pilkington explains this in its Activ™ Self-Cleaning Glass Guide.
• Reflective or Mirror Coatings: Reflect more light than they transmit, offering privacy while reducing glare.
  Common in offices or commercial façades, but increasingly popular in modern homes.

Benefits for energy and comfort

In the UK, windows account for up to 20% of heat loss in poorly insulated homes.
Coated glass dramatically reduces this, lowering heating bills and improving comfort year-round.
Verified testing by the Energy Saving Trust shows that high-performance coated glazing can save up to £300 annually for an average household.

• ✅ Keeps heat inside during winter
• ✅ Reflects excess solar gain in summer
• ✅ Reduces condensation on inner panes
• ✅ Improves EPC ratings and sustainability

For deeper UK efficiency standards, see the official Future Homes & Buildings Standards Consultation.

Sun protection and UV control

Prolonged UV exposure can fade fabrics, flooring, and artwork.
Modern solar coatings filter out up to 99% of harmful ultraviolet rays while allowing natural daylight.
Saint-Gobain’s PLANITHERM® range demonstrates how a single coating can combine solar protection and insulation.

• ☀️ Protects furniture and finishes from UV damage
• 🌡 Helps maintain balanced indoor temperatures
• 🌤 Improves visual comfort by reducing glare

Choosing the right coated glass

The best choice depends on orientation, window size, and use:

• North-facing: Choose Low-E coatings to retain warmth.
• South-facing: Pick solar-control glass like COOL-LITE® to block excess heat.
• Bathrooms and façades: Combine coatings with tempered safety glass for durability and compliance.

For installers, UK technical standards are covered under BSI Glass & Glazing, which outlines approved testing and performance requirements.

Frequently Asked Questions

What are Low-E coatings made of?
They typically consist of thin metal oxide layers that reflect infrared heat while allowing visible light to pass. See Guardian Glass – Low-E explainer.

Do coated windows block UV rays?
Yes — solar control coatings like PLANITHERM® or COOL-LITE® can block up to 99% of UV radiation.

Are coated glass units recyclable?
Yes. Coated glass can be remelted and reused; see WRAP UK’s recycling guidelines for glass best practices.

References:
Energy Saving Trust – Windows & Doors ·
Guardian Glass – Low-E Coatings ·
Saint-Gobain – COOL-LITE® Solar Control ·
Saint-Gobain – PLANITHERM® ·
Pilkington – Activ™ Self-Cleaning Glass ·
BSI – Glass & Glazing ·
Gov.uk – Future Homes & Buildings Standards ·
WRAP UK – Glass Recycling