Glazing Options for Sash Windows
Explore Glazing Types for Your Sash Windows
Choosing the right glazing depends on what matters most to you – insulation, sound reduction, privacy, security or all four. We offer a range of options to suit different needs, all fitted into our made-to-order timber sash windows.
Double Glazing for Sash Windows
We offer argon-filled double glazing units with warm edge spacers as standard for our sash windows. These units provide strong thermal performance while maintaining traditional sash proportions.
You can customise your glazing based on your project needs – including whether toughened safety glass is required to meet Building Regulations. We’re happy to advise during the design stage if you’re unsure.
Key Features:
U-values: 1.1 W/m²K (centre pane)
Spacer bar colour: white, black, grey, brown
Argon gas fill
Toughened glass option available (recommended where required by Building Regulations)
🟢 Optional Upgrades:
Acoustic glass
Laminated glass
Acoustic & Laminated Options
We offer glazing upgrades designed to improve security or reduce external noise:
Acoustic Glass: Laminated with sound-reducing interlayer to reduce airborne noise.
Laminated Safety Glass: Holds together if broken and increases resistance against forced entry.
Available thicknesses: 6.4mm, 8.8mm, and 10.8mm depending on requirement.
✅ Ideal for bedrooms, front elevations, or city locations.- Read more about acoustic glass in sash windows here
Vacuum Glazing
Vacuum glazing is ideal where slimline appearance and energy performance are both important. With a total thickness of just 8.3mm, it offers the visual qualities of traditional single glazing while delivering thermal performance better than triple glazing.
Learn more about Vacuum Glazing here.
Key Features:
U-value: 0.4 W/m²K (centre pane)
Total thickness: 8.3mm
Toughened outer and inner panes
15-year manufacturer warranty
🟢 Suitable for conservation areas (subject to approval)
Obscure and Decorative Glazing
Ideal for bathrooms, hallways or side windows where privacy is needed. Choose from a range of glass types:
Satin (Etched) Glass – for a uniform frosted look
Reeded Glass – fluted vertical lines for a subtle texture
- Sandblasted Designs – custom shapes or patterns available upon request
- Obscure Patterned Glass – classic or contemporary textures to add privacy and character
All options are available as part of our double or single glazed units.
View glass options for our wooden sliding sash window
Warm Edge Spacer Bars for Sash Windows
The spacer bar is the strip that separates the panes of glass within a double-glazed unit — it’s what you see when looking between the two panes. In traditional double glazing, this was usually aluminium, which conducts heat and can reduce the energy efficiency of the window.
Today, we use warm edge spacer bars as standard in our double-glazed sash windows. These are made from an insulating composite material that helps reduce heat loss through the edges of the unit. This leads to improved thermal performance, lower heating bills, and reduced condensation around the glass perimeter.
Key Details:
Standard on all sash windows using double glazing (unless aluminium is specifically required)
Spacer bar colour is matched to your paint finish where possible
Reduces heat transfer and helps lower CO₂ emissions
Can reduce perimeter condensation by up to 70%
Unless otherwise requested, we’ll select a spacer bar colour that suits your chosen paint finish — for example, white windows will typically be supplied with white warm edge spacers.
Glazing FAQs
Q: Do I need toughened glass?
A: Toughened safety glass is recommended where Building Regulations require it – typically in doors, low-level windows, or areas near stairs and bathrooms. If you’re unsure, we’re happy to advise.
Q: Can I choose different glass types for top and bottom sashes?
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Q: What’s the difference between vacuum and double glazing?
A: Vacuum glazing is thinner (8.3mm total) but provides better insulation than standard double glazing. It’s ideal when slimline appearance or conservation compliance is important.
Q: Is acoustic glass worth it?
A: If your property is near a busy road, railway, or other noise source, acoustic glass can significantly reduce external sound. It’s a laminated unit with a special interlayer to disrupt sound waves.
Q: Do you offer obscure or privacy glass?
A: Yes. We offer satin, reeded, patterned, and sandblasted options for any glazing type. These are commonly used in bathrooms or hallway windows.
Q: What is a warm edge spacer bar?
A: It’s the insulating strip between the panes of a double-glazed unit. Unlike older aluminium spacers, warm edge spacers help reduce heat loss and condensation.
Q: Can I use laminated glass in all sash windows?
A: Yes — laminated glass is available in various thicknesses and can be used for safety, security, or acoustic performance.
Q: Can I use laminated glass in all sash windows?
A: Yes — laminated glass is available in various thicknesses and can be used for safety, security, or acoustic performance.
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