Call us: 01773 300510

Can existing sash windows be double glazed?

Homepage > Sash Windows > Can existing sash windows be double glazed?
Can existing sash windows be double glazed?

Can existing sash windows be double glazed?

Reading Time: 3 Minutes
Published on: July 25th, 2023

Read Now

Can existing sash windows be double glazed?

Yes, existing sash windows can be double glazed with modern slim glazing technology, offering better thermal efficiency and soundproofing while preserving their charm. Vacuum glazing is an innovative technique that can be used to maintain the appearance of single-glazed profiles while providing the benefits of double glazing, such as enhanced insulation and soundproofing.

When it comes to preserving the authentic character of historic properties, including listed buildings with their distinct architectural charm, addressing the single glazing in original sash windows poses a unique challenge. Many of these buildings still boast their original single-glazed sash windows, which, while captivating in appearance, may lack the energy efficiency required for modern living. Finding a solution that maintains the visual integrity of these single-glazed profiles while enhancing their performance is of utmost importance.

Preserving Original Units

One of the primary concerns when upgrading single glazing is to replicate the appearance of the original units. The unique charm and historical significance of sash windows lie in their individual glazing bars and slender frames, which may have been single glazed during their era.

Energy-Efficient Alternatives

To replace single glazing with more energy-efficient options, two noteworthy alternatives stand out: slim double glazing and vacuum glazing.

Slim Double Glazing

Slim double glazing involves fitting double glazing within the existing sash window frames while preserving the slender profile of the bars. Although it improves energy efficiency compared to single glazing, some challenges persist.

  •  Unit Failure: With slim double glazing, there is a risk of unit failure over time, which may result in misting or reduced performance.
  • Double Reflection: The narrow space between the panes in slim double glazing can lead to a double reflection effect, which can be visually distracting.

Vacuum Glazing

Vacuum glazing is emerging as a viable alternative for upgrading single-glazed sash windows. It offers remarkable thermal insulation by utilizing a vacuum-sealed cavity between two ultra-thin glass panes. This innovative technology not only enhances energy efficiency but also addresses the challenges faced with slim double glazing.

Advantages of Vacuum Glazing: 

Vacuum glazing presents several advantages for maintaining single glazed profiles:

  • Enhanced Insulation: The vacuum-sealed cavity virtually eliminates heat transfer, providing superior thermal insulation and reducing energy consumption.
  • No Double Reflection: Vacuum glazing avoids the issue of double reflection, ensuring clear visibility through the windows.
  • Durability: The absence of air or gas between the panes reduces the risk of unit failure, resulting in a longer-lasting and highly efficient glazing solution.

Replicating Georgian, Victorian, and Edwardian Glazing Bars

Preserving the unique characteristics of Georgian, Victorian, and Edwardian glazing bars during the transition to modern double glazing is crucial. With advances in manufacturing techniques, it is now possible to replicate these historic profiles in contemporary double glazing. This allows property owners to maintain the original aesthetic appeal of their sash windows while benefiting from the advantages of energy-efficient vacuum glazing.

How do sash windows work? A diagram of an edwardian sash windows
Edwardian Sash Window
Victorian heritage sash window with authentic glazing bars
Victorian Sash Window
Georgian Heritage sash windows with 6 over 6 glazing bars
Georgian Sash Window

In conclusion, while single glazing in listed buildings and historic properties presents challenges in terms of energy efficiency, modern advancements offer viable solutions. Vacuum glazing, with its superior insulation and preservation of the original single-glazed profiles, emerges as a compelling alternative. By embracing this innovative technology and replicating the unique glazing bars of bygone eras in contemporary double glazing, property owners can strike the perfect balance between preserving history and embracing sustainability for the future.