Spacer Bars
When you think about double glazing, you might focus on the glass or the frame, but there’s a small, often overlooked component that plays a big role in your windows’ performance: Spacer Bars. These unassuming components that sit between the glass panes at the perimeter of the double glazed units effect the units lifespan, thermal efficiency, noise transmission and the instance of perimeter condensation. In this article we will touch on the different types of Spacer Bars in double glazing and explore how choosing the right type can make a significant difference in your home’s comfort and energy bills.
The Role of Spacer Bars in Double Glazed Windows
Spacer Bars are placed between the panes of glass in a double or triple-glazed window to maintain a consistent gap and to facilitate a hermetic seal around the perimeter, which is essential for the window’s insulating properties. By creating this gap, Spacer Bars help trap air or inert gases like argon between the panes, forming a thermal barrier that reduces heat transfer and improves energy efficiency. This role is particularly crucial in climates like Scotland’s, where retaining heat during the colder months is a priority.
Additionally, Spacer Bars contribute to the structural integrity of the window unit by holding the panes securely in place. They also help in preventing condensation by creating a sealed environment that keeps moisture out, thereby extending the life of the window and maintaining its performance.
What Are Spacer Bars Made Of?
The composition of Spacer Bars plays a crucial role in their effectiveness. Historically, aluminium was the primary material used due to its strength and ease of manufacturing. Traditional Aluminium Spacer bars are tubular and filled with an anhydrous material that absorbs any water vapour from the space between the panes.
If the edge seals, frequently formed with gun applied hot butyl sealant, fail the anhydrous material can become saturated allowing moisture to evaporate back into the cavity when it is warm condensing on the internal glass surfaces when it is cold often depositing a white efflorescence on the internal glass surfaces. Aluminium has a high thermal conductivity, which can lead to heat loss at the edges of the window, known as “cold bridging.” Where thermally conductive spacer bars are used the internal glass temperature at the edges of the sealed units can drop to close to the external temperature producing a cold zone around the edges where condensation can result. This makes it less suitable for modern energy-efficient homes.
The most significant advancements have been made with composite materials. These include polymers, foams, and other non-metallic materials that have much lower thermal conductivity, which greatly reduces heat transfer. Composite Spacers, often referred to as Warm Edge Spacers, are particularly effective in mitigating peripheral condensation and improving the window’s overall thermal performance.
What Types of Spacer Bars Are Available?
Choosing the right type of Spacer Bar can greatly influence the performance of your windows. Here are the main types of Spacer Bars available:
1. Standard Aluminium Spacers:
These are the most basic, least expensive and commonly used Spacers, made from aluminium. They provide good structural support but are not the most energy-efficient option due to their high thermal conductivity.
2. Warm Edge Spacers:
These Spacers are designed to reduce heat loss and to help prevent peripheral condensation. Made from materials with low thermal conductivity Warm Edge Spacers can significantly improve the energy efficiency of your windows. They can reduce perimeter conductive heat loss by up to 65% compared to standard aluminium Spacers.
3. Super Spacers:
A type of Warm Edge Spacer, Super Spacers are made from flexible foam materials that offer superior thermal insulation. They are particularly effective in reducing condensation and providing greater comfort by maintaining a consistent temperature across the window surface.
How Do Spacer Bars Improve Energy Efficiency?
Spacer Bars play a pivotal role in enhancing the energy efficiency of windows. By maintaining a uniform gap between the panes, they help to reduce heat transfer, which lowers the overall U-value of the window—a key indicator of insulation performance. A lower U-value means less heat is lost, which is particularly beneficial in colder climates like Scotland’s.
Thermally enhanced spacer bars contribute to energy savings and reduced heating costs and enhanced levels of comfort for your home. Additionally, these Spacers minimise condensation by keeping the inner glass surfaces warmer, thus preventing moisture build-up and the associated risks of mould and damage.
What Design Options Are Available for Spacer Bars?
Spacer Bars are not just functional; they can also be customised to suit the design aesthetics of your windows. Modern Spacer Bars come in a variety of colours—such as black, white, grey, and metallic finishes—allowing them to blend seamlessly with the window frame or stand out as a design feature.
The width of the Spacer Bar dictates the gap between the panes of glass, which plays a crucial role in the insulating performance of the window. A wider Spacer Bar can improve the window’s ability to insulate up to the point that the increased gap results in convection currents within the gap. The optimal width depends on the overall design of the window and the specific requirements of your home.
Choosing the right combination of material, colour, and width for your Spacer Bars can enhance both the energy efficiency and aesthetic appeal of your windows. Window Advice Centre provides expert guidance to help you make informed decisions that align with your home’s needs and your personal style.
Conclusion: Why Spacer Bars Matter for Your Double Glazing
Spacer Bars are an important though often overlooked, component of double-glazed windows. Their role in maintaining the gap between glass panes and reducing heat transfer is essential for enhancing the energy efficiency, comfort, and longevity of your windows. By choosing the right type of Spacer—whether it’s a standard aluminium Spacer, a more advanced Warm Edge Spacer, or a high-performance Super Spacer—you can significantly improve your home’s thermal performance.
The choice of Spacer Bars also offers a range of design options that allow you to customise the appearance of your windows, with various colours and widths available to match your aesthetic preferences. Additionally, selecting the correct Spacer width is influential in achieving the best possible insulation for your home.
For over 40 Years Window Advice Centre, has been available without charge or obligation to help homeowners across central Scotland make informed decisions about their replacement windows and doors. The impartial expert advice provided by Window Advice Centre can help you better understand the variation in materials, construction methods and performance outcomes that are available and help you ensure that your investment in new windows will provide maximum comfort and value for years to come.
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