Debunking Concerns about VIG (Vacuum Insulated) Glass

Debunking Concerns About VIG Glass

A Comprehensive Assessment of Vacuum Glazing compared to Slim Double Glazing

Introduction:

Historic window upgrades play a crucial role in preserving the architectural integrity of our heritage buildings while meeting the demands of energy efficiency and sustainability. Within this context, the choice of glazing is of paramount importance. As the market explores innovative solutions, it is essential to adopt a holistic approach that considers not only thermal performance but also factors such as functionality, aesthetics, and long-term sustainability.

In this white paper, we aim to address common concerns and misconceptions surrounding vacuum insulated glass (VIG), also known as vacuum glazing. By providing a comprehensive analysis of the performance, benefits, and compatibility of vacuum glazing in historic window upgrades, we aim to debunk prevailing myths and offer a wellinformed perspective.

The white paper is structured to delve into various aspects of vacuum glazing, including insulation performance, mitigation of dew-point shifting, advancements in design and compatibility, dispelling concerns about spacers, the balance between preservation and modernisation, sustainability considerations, and other relevant factors. By examining each topic in detail, we aim to present a comprehensive understanding of vacuum glazing as a viable solution for historic window upgrades.

It is important to note that this white paper serves as a guide and reference, providing valuable insights and analysis. However, it is not intended to replace professional advice, and individual assessments based on specific project requirements are strongly recommended. Now, let us explore the intricacies of vacuum glazing and debunk the concerns surrounding its implementation in historic window upgrades.

Evaluating Insulation Performance:

One of the key considerations when evaluating glazing options for historic window upgrades is insulation performance. Vacuum glazing, while often hailed as a cutting-edge solution, has raised concerns regarding its average insulation values and their drop towards the edge of the unit.

However, it is crucial to examine specific products within the vacuum glazing market to gain a more accurate understanding of their insulation capabilities. LandVac, a leading vacuum glazing product, stands out with its impressive centre-pane U-value of 0.4W/m²K. This level of thermal insulation surpasses that of many slim double glazed units, making LandVac a compelling option for those seeking superior thermal performance.

Moreover, it is important to consider the long-term performance advantages of vacuum glazing over slim double glazing. While slim double glazing may initially provide comparable insulation values, over time, the performance of these units can deteriorate due to gas loss through the seal. In contrast, vacuum glazing systems, such as LandVac, maintain their thermal performance more effectively, ensuring lasting energy efficiency for historic window upgrades.

By carefully evaluating the insulation performance of vacuum glazing and understanding the advantages it offers over slim double glazing in terms of long-term performance, we can make informed decisions when selecting glazing solutions for historic buildings.

Mitigating Risks of Dew-Point Shifting:

When considering glazing options for historic buildings, concerns regarding dew-point shifting and interstitial condensation must be addressed. These risks arise from the potential movement of the dewpoint to the walls, leading to moisture accumulation and potential degradation of the building materials, particularly in the presence of nonbreathable plaster and paint.

To mitigate these risks, proper installation practices are crucial. This includes ensuring effective sealing and insulation measures to create a barrier that prevents moisture from reaching the walls. By implementing these measures, the potential for dew-point shifting and interstitial condensation can be significantly reduced, safeguarding the integrity of historic buildings.

Taking a holistic approach is essential when addressing these concerns. It is not enough to focus solely on the glazing solution; rather, a comprehensive strategy that considers the entire building envelope and its interaction with the glazing is necessary. This approach encompasses proper ventilation, insulation, and moisture management throughout the building, ensuring improved comfort and sustainability for occupants while preserving the historic fabric of the structure.

By recognising the risks of dew-point shifting and interstitial condensation, adopting proper installation practices, and embracing a holistic approach, we can effectively mitigate these concerns and create a more comfortable and sustainable environment in historic buildings.

Advancements in Design and Compatibility:

One of the concerns often raised regarding vacuum glazing systems is their compatibility with existing window structures, particularly in relation to rebate dimensions, sight lines, and nozzles. However, it’s important to note that significant progress has been made in addressing these issues, ensuring a seamless integration of vacuum glazing in historic buildings.

The continuous evolution of technology and design has paved the way for innovative solutions that cater to specific architectural styles, such as Georgian glazing bars. Manufacturers are actively developing vacuum glazing systems that can accommodate these traditional design elements without compromising performance or aesthetics. This allows for the preservation of the building’s historic character while reaping the benefits of improved thermal insulation.

Mechanically fixed plant systems present another noteworthy advancement in design and compatibility. By incorporating mechanical fixings onto the glazing bars, vacuum glazing can achieve enhanced performance, improved aesthetics, and increased security. These fixings provide additional support, ensuring a secure and durable installation while maintaining the desired sight lines and preserving the overall architectural integrity of the building.

These advancements in design and compatibility demonstrate the commitment of industry stakeholders to overcome the challenges associated with integrating vacuum glazing into historic buildings. By addressing concerns about rebate dimensions, sight lines, and nozzles, and by embracing innovative solutions such as mechanically fixed plant systems, we can achieve a harmonious balance between performance, aesthetics, and the preservation of historic architectural features.

Dispelling Concerns About Spacers:

Spacers play a crucial role in vacuum glazing systems by maintaining the appropriate distance between glass panes. While concerns may arise regarding their impact on aesthetics and performance, it’s important to understand the advancements made in spacer design that address these concerns.

One notable advancement is the introduction of translucent grey spacers, such as those offered by LandVac. These spacers are designed to be less noticeable, blending more seamlessly with the overall appearance of the window. The translucent nature of these spacers helps minimise their visual impact, ensuring that the focus remains on the glazing itself rather than the spacer.

Additionally, it’s worth noting that the occurrence of spacers dropping to the bottom is extremely rare and not a widespread issue. Modern vacuum glazing systems are engineered with robust and reliable spacer designs that ensure long-term stability. Extensive research and development have been conducted to minimise the risk of such incidents, providing confidence in the durability and performance of vacuum glazing units.

By recognising the necessity of spacers in maintaining proper pane distance, acknowledging advancements in spacer design like translucent grey spacers, and clarifying the infrequent occurrence of spacers dropping to the bottom, we can dispel concerns and instil confidence in the reliability and effectiveness of vacuum glazing systems.

Balancing Preservation and Modernisation:

Preserving the character and integrity of historic windows is a significant consideration when exploring options for energy efficiency upgrades. While the desire for improved performance is essential, it is crucial to find a balance that respects the unique aesthetics and historical significance of these windows.

One approach to strike this balance is by incorporating alternative options that blend historic glass types with improved performance. By utilising advancements in technology, it is now possible to enhance the thermal properties of historic glass while maintaining its original appearance. This allows for the preservation of the window’s character while achieving increased energy efficiency.

It is important to emphasise the importance of finding a harmonious coexistence between preservation and meeting energy efficiency requirements. Historic windows contribute to the architectural heritage and charm of a building, and their alteration should be approached with care. Striking a balance that respects the historic fabric while enhancing energy performance not only benefits the building but also maintains its cultural value.

By considering alternative options that integrate historic glass types with improved performance and adopting a mindset of balance, we can successfully preserve the character and integrity of historic windows while meeting modern energy efficiency demands. This approach ensures that our heritage is safeguarded for future generations to appreciate.

Sustainability and Carbon Footprint Considerations

When evaluating the environmental impact of glazing options, it is important to consider a holistic range of factors beyond just the manufacturing location. While the distance of transportation can have an impact, it is often overshadowed by other significant factors in terms of sustainability and carbon footprint.

Vacuum glazing offers several advantages when it comes to sustainability. Firstly, it requires lower energy inputs during manufacturing compared to other glazing options. This helps reduce the overall carbon emissions associated with its production. Additionally, the superior thermal performance of vacuum glazing contributes to improved energy efficiency and heat retention in buildings, reducing the need for excessive heating or cooling.

Another aspect to consider is the product lifespan. Vacuum glazing is known for its durability and longevity, which means that it can remain in service for extended periods without the need for frequent replacement. This extended lifespan further enhances its sustainability credentials by reducing waste generation.

Furthermore, vacuum glazing exhibits excellent recyclability. At the end of its lifecycle, the glass and other materials used in vacuum glazing can be recycled, contributing to a circular economy and minimising waste.

To make an informed assessment, it is important to consider the overall benefits of vacuum glazing against the transportation factor. While transportation does contribute to the carbon footprint, the energy savings and long-term sustainability advantages offered by vacuum glazing often outweigh the transport emissions.

By taking a comprehensive and holistic approach to evaluating the sustainability and carbon footprint of glazing options, it becomes clear that vacuum glazing holds promise as an environmentally friendly choice. Its energy efficiency, durability, recyclability, and long lifespan contribute to a reduced environmental impact overall.

Additional Factors to Consider

In addition to the previously discussed aspects, there are several other factors to consider when evaluating vacuum glazing as a glazing solution for historic window upgrades. These factors go beyond energy efficiency and sustainability and encompass other important considerations for homeowners and building occupants.

One crucial factor to take into account is the longevity of vacuum glazing. The extended lifespan of vacuum glazing systems plays a significant role in reducing the carbon footprint over time. With proper maintenance and care, vacuum glazing can provide reliable performance for decades, minimising the need for replacements and reducing overall environmental impact.

Another important consideration is the impact on security and longevity when altering glazing bars for traditional double glazed units. Historic windows often have unique glazing bars that contribute to the character and architectural integrity of the building. Altering these bars to accommodate traditional double glazed units can compromise the original aesthetics and potentially affect the security of the windows. Vacuum glazing offers a solution that preserves the original glazing bars while providing improved thermal performance, ensuring the longevity and security of historic windows.

Acoustic performance is also a significant factor for homeowner comfort. Living in urban areas or near busy streets can expose homeowners to high levels of noise pollution. Vacuum glazing, with its enhanced insulation properties, helps reduce external noise infiltration, creating a quieter and more peaceful indoor environment. The superior acoustic ratings of vacuum glazing make it an attractive choice for homeowners seeking both energy efficiency and acoustic comfort.

Considering these additional factors alongside energy efficiency and sustainability allows for a comprehensive assessment of vacuum glazing as a glazing solution for historic window upgrades. Its longevity, preservation of original glazing bars, and acoustic performance benefits contribute to an overall enhanced living experience while minimising environmental impact.

Conclusion

In this white paper, we have explored the various aspects of vacuum glazing as a glazing solution for historic window upgrades. By taking a holistic approach and considering factors such as insulation performance, dew-point shifting, design compatibility, spacers, preservation, sustainability, and additional considerations, we have gained valuable insights into the potential of vacuum glazing.

Throughout our assessment, it is evident that vacuum glazing holds promise as a viable solution for improving the functionality, aesthetics, and sustainability of historic windows. Its impressive insulation performance, long-term effectiveness, and advancements in design and compatibility address the concerns associated with traditional double glazed units. Moreover, the use of translucent grey spacers and the rare occurrence of spacers dropping to the bottom add to the appeal of vacuum glazing.

We have also highlighted the importance of balancing preservation and modernisation, as well as considering factors such as acoustic performance and the carbon footprint in the decision-making process. By striking a balance between historic preservation and energy efficiency requirements, vacuum glazing offers a solution that respects the character of historic windows while providing improved performance.

As we conclude this white paper, it is important to note that the field of vacuum glazing is continuously evolving. Ongoing research and development efforts are dedicated to addressing the concerns and further improving the performance and compatibility of vacuum glazing systems. We remain committed to staying at the forefront of these advancements and providing even better vacuum glazing options in the future.

By considering the insights presented in this white paper, stakeholders involved in historic window upgrades can make informed decisions that enhance the functionality, aesthetics, and sustainability of their buildings. Vacuum glazing offers a compelling solution that combines thermal performance, preservation, and energy efficiency, paving the way for a more sustainable future for historic buildings.

Higher

Slimmer profile

DATA TABLES

SHAPES

LandVac is available in a variety of shapes. Here are just a few examples to inspire your project:

Width to Height maximum ratio 1:6 for 8.3mm. Bigger than that and it will be 10.3mm

Any shape with a right angle and single point of radius. Isosceles triangles or right angled triangles with a hypotenuse greater that 370mm.

CAD drawings must be supplied for any shape orders.

General Criteria and Specification Notes

Maximum Unit Size 1500mm x 2500mm

Minimum Unit Size 300mm x 300mm. Please note that minimum unit size for pricing is 0.3m2.

All LandVac Glass is toughened and has been certified to BS12150-1.

U-value certified using hot box testing at IFT Rosenheim on 9.3 unit.

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