How to Choose the Best Glass for Your Roof Lantern

Size Matters

The size of your roof lantern significantly impacts heat and light levels in your space. Larger lanterns naturally allow more sunlight, which can lead to increased glare and heat build-up. For example, in orangery-style extensions where the roof lantern dominates the flat roof, natural light floods the space below—a key feature of roof lanterns. However, excessive heat and glare can make the room uncomfortable without proper planning.

Solar Glass for Larger Lanterns

Consider tinted solar glass, also known as “anti-sun” glass, to combat these issues. Available in Neutral (Grey) or Blue tints, solar glass reduces heat and UV penetration by approximately 25% compared to clear glass. While this helps maintain a comfortable temperature, it also lowers light transmission by around 35%, meaning a space will feel slightly dimmer than with clear glass.

At Just Roof Lanterns, we often recommend Neutral (Grey) tints for a more natural appearance, particularly in period properties. While Blue tints are an option, they can sometimes appear overly commercial. Ultimately, solar glass is a prudent choice for larger roof lanterns to manage heat and glare effectively.

Orientation and Sunlight

The orientation of your roof lantern also plays a vital role in glass selection.

• South-facing extensions receive the most sunlight throughout the day, increasing heat build-up, UV exposure, and glare. In these cases, solar glass is an excellent option.
• North-facing extensions or those shaded by trees or nearby buildings may benefit from clear glass to maximise light transmission. While clear glass allows more heat and light into the room, it’s a better choice for spaces that don’t experience direct sunlight.

Key Tip: Avoid solar glass for shady or north-facing locations to prevent unnecessary light reduction. Opt for clear glass to ensure your space is as bright as possible.

How You Use the Space

Your room’s function influences the best glass choice.

• For secondary spaces (stairwells, boot rooms, hallways), clear glass is ideal for allowing as much natural light in as possible.
• For primary living spaces (kitchens, family rooms), solar glass is often the better option. These rooms are used year-round, and controlling temperature and light levels is essential for comfort.

Solar glass also helps protect furniture, flooring, and fabrics from fading due to UV exposure, making it a wise investment for spaces with valuable furnishings.

Ventilation Enhances Comfort

Choosing solar glass goes hand-in-hand with deciding whether to include ventilation. An opening vent helps release hot air and improves airflow, making your space more comfortable.

💡 Ventilation Options:

• Manual Opening Vents – Affordable and simple to use.
• Electric Opening Vents – Convenient, with the option to automate based on temperature.

While ventilation reduces heat build-up, glare may still be a concern, especially in larger lanterns. For more details, refer to our dedicated article on ventilation options.

Maximising Thermal Efficiency

Thermal performance is another key consideration when selecting glass. While glass roofs are less insulated than tiled roofs, modern technology ensures high thermal efficiency.

• Standard double-glazed units have a U-value of 1.2, offering good insulation.
• Upgrading to a U-value of 1.0 improves thermal efficiency by 17% for only about 5% additional cost.
• Triple glazing (U-value of 0.6) provides a 50% improvement in thermal performance but costs approximately 30% more than double glazing.

For extensions with large amounts of glazing, a lower U-value can enhance energy efficiency and comfort.

Conclusion

Selecting the best glass for your roof lantern requires balancing size, orientation, room function, and thermal efficiency. By considering these factors, you can ensure your roof lantern enhances your space beautifully and comfortably.

🔹 Need expert advice? Choosing the perfect glass for your roof lantern can make all the difference in comfort and aesthetics. If you're unsure which option is best for your home, our expert team at Just Roof Lanterns is here to help—get in touch today for tailored advice!