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At CN Glass, we’ve built a solid reputation as a trusted local manufacturer and supplier of high-performance double glazed sealed units. With over 55 years of industry experience, our units are crafted in-house at our Oxfordshire facility and are fully compliant with BS EN1279 Parts 2 & 3, ensuring excellent thermal performance, long-lasting seals, and full peace of mind.
Whether you’re a trade customer, property developer, or homeowner, we deliver consistent quality and technical expertise across Oxfordshire and the Cotswolds areas. With CN Glass, you can expect reliable, made-to-measure sealed double glazed units built to last.
Why Choose CN Glass for Your Double Glazed Sealed Units?
Choosing the right manufacturer of residential or commercial double glazed units can make a big difference in performance, cost-efficiency, and lifespan. Here’s what sets CN Glass apart:
- Manufactured in-house to BS EN1279 Parts 2 & 3 – our sealed units meet rigorous British Standards for moisture resistance, gas retention, and overall durability.
- Supply-only or full installation service – whether you need the units delivered or fully installed, we’re flexible to your needs.
- Up to 10-year warranty – when fitted by our expert team, your double or triple glazed sealed units come with a long-term guarantee for added confidence.
- Local service with nationwide capabilities – based in Oxfordshire, we serve both local clients and larger national contracts.
- Trusted by trade and domestic customers alike – we’ve built long-standing relationships with our clients, thanks to our friendly, professional service and technical know-how.
Our Double Glazed Sealed Unit Options
We offer a wide range of sealed unit configurations and performance enhancements to suit different properties, specifications, and budgets:
- Aluminium or warm edge spacer bars – choose from traditional aluminium or energy-efficient warm edge technology to reduce heat loss and condensation.
- Argon or krypton gas-filled units – improve insulation with either argon (most popular) or higher-performing krypton gas.
- Custom cavity thicknesses – common sizes include 14mm, 20mm, 24mm, and 28mm cavities, with bespoke options available.
- Acoustic laminated options – reduce external noise with specialist laminated glass, ideal for properties in busy areas.
- Triple-glazed unit upgrades – for enhanced insulation, we also manufacture triple glazed sealed units.
Technical Specifications & Performance
How a sealed unit with double glazing works
Each unit is made up of two panes of glass separated by a spacer bar and sealed to create an airtight cavity. This cavity is often filled with inert gas to improve insulation. The sealed unit works by reducing heat transfer and limiting condensation on interior surfaces.
U-values explained
U-values measure a window's ability to retain heat. The lower the U-value, the better the insulation. Modern sealed double glazed units typically achieve U-values around 1.1 to 1.4 W/m²K. Our krypton-filled or triple-glazed units can offer even better performance for highly energy-efficient projects.
Common thicknesses and spacer types
Most applications use 24mm-thick units (4-16-4 configuration), but we also manufacture thinner or thicker options depending on the window profile. Besides aluminium spacers, warm edge or thermal break spacer bars are increasingly popular due to their low thermal conductivity and ability to reduce perimeter condensation.
Benefits of triple glazing
Triple glazed sealed units include an extra pane and cavity, providing superior insulation and noise control. While they’re relatively more expensive, they’re worth considering for properties aiming for low-energy standards or those in very cold environments.
Thermal and acoustic performance
Our sealed units are designed to reduce heat loss, block out noise, and minimise condensation. Options like laminated acoustic glass and advanced gas fills give you flexibility to match performance with your specific project requirements.
How We Manufacture Our Sealed Units
At CN Glass, each sealed unit (double glazing) is produced entirely in-house at our Oxfordshire factory. This enables us to maintain tight control over quality and turnaround times.
- Glass cutting – sheets are either precision-cut by hand or automated machinery, depending on size and complexity.
- Toughening – where needed, panes are sent through our toughening process to meet safety glass regulations.
- Spacer bar insertion – spacer bars are inserted with accuracy, ensuring proper cavity depth and alignment.
- Gas filling – we use argon or krypton gas to fill the cavities to improve thermal performance.
- Edge sealing – high-grade perimeter sealants are applied for long-lasting moisture resistance. These can be hand-applied for bespoke windows for maximum flexibility.
- Desiccant use – moisture-absorbing materials are added inside spacer bars to prevent internal condensation.
All sealed doubled glaze units are tested and inspected to ensure they meet our high manufacturing standards and your project’s specific requirements.
Recent Projects
We’ve supplied and installed sealed units for a wide range of residential and commercial projects, including local schools, new-build developments, office refurbishments, and listed buildings across Oxfordshire and beyond. Our ability to customise sealed double glazed units and offer reliable turnaround times has made us a trusted partner for builders, glaziers, and homeowners alike.
Salisbury Cathedral’s Refectory Glass Roof Restoration
CN Glass was entrusted with the restoration of the glass roof at Salisbury Cathedral’s Refectory—a project aimed at improving energy efficiency, enhancing visibility, and ensuring long-term durability.
FAQs
- What are double glazed sealed units?
They’re two panes of glass sealed together with a spacer bar to form an insulated unit. The sealed cavity between the panes helps improve thermal efficiency and reduce condensation.
- What’s the difference between argon and krypton gas filling?
Both are inert gases that improve insulation. Argon is more common and cost-effective, while krypton offers better performance in thinner cavities, making it ideal for slimmer profiles or higher-spec applications.
- Can you replace failed or misted sealed units?
Yes, we can manufacture replacements for misted or blown units and either supply them to your installer or carry out the installation ourselves.
- What spacer bar options do you offer?
We supply both aluminium and warm edge spacer bars for our commercial double glazed units. Warm edge spacers are more energy efficient and help reduce condensation on the glass edges.
- How long do sealed units typically last?
With proper installation and materials, double glazed sealed units generally last 15-25 years. Our units come with up to a 10-year guarantee when installed by CN Glass.
- Are triple glazed sealed units worth the extra cost?
For most standard homes, a high-quality sealed unit double glazing offers excellent value. But if you’re in an exposed location or building to higher energy standards, triple glazing can provide noticeable benefits.
Triple-glazing will cost about 20% more than the standard double-glazing cost and reduce the overall heat loss by about 5%.
Contact CN Glass for High-Quality Sealed Units
Need new sealed units for your property? Whether you’re after supply-only or a full installation service, we’re here to help. Get in touch to order made-to-measure sealed units or request a free quote.
Address:
Norton House, Beaumont Road
Banbury, Oxfordshire OX16 1SD
Phone Number:
Let’s get in touch
Contact CN Glass today to arrange a quotation. Reach us in the following options.
Address:
Norton House, Beaumont Road
Banbury, Oxfordshire OX16 1SD
Phone Number:
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