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Double-Glazed Windows

We offer a full range of high-performance glazing options for development projects across everything from period homes to high-end new build developments.

Whether you’re working on a sensitive renovation, a multi-property development, or a bespoke architectural design, we help you specify the ideal glazing to achieve the level of performance you need. Contact us to arrange a consultation and select the right design and glazing today.

Our range of double-glazed windows

We offer high-performance double glazing across our full range of windows, including heritage designs. From slimline glazing for conservation areas to vacuum technology for properties with limited frame depth, we’ll tailor everything to your needs.

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To explore our range of sustainable timber windows and doors and imagine the possibilities for your project, fill in the form to download our brochure now.

    Your double glazing options

    Our glazing options are designed to support energy efficiency, acoustic comfort, security, and long-term performance. We can deliver the following specifications:

    • 24mm Standard double glazing: This option is the ideal balance of value and performance. Our standard 4/16/4 argon-filled units offer excellent thermal performance, helping to reduce heat loss, limit condensation, and improve overall comfort throughout the year. It’s widely used in both residential installations and developer projects due to its reliable efficiency and cost-effectiveness. You’ll find it perfect for modern homes, refurbishments, and large-volume developments.
    • 24mm Toughened double glazing: This type has been manufactured with enhanced safety for higher-risk and high-traffic areas, with up to 5 times the strength of normal glass and far greater resistance to accidental damage. Toughened double glazing is designed to meet building and safety regulations in areas such as low-level glazing, bathrooms, and busy entrances, and also breaks into blunt fragments on impact. It’s ideal for properties requiring enhanced impact resistance.
    • 24mm Standard (non-toughened glazing): Our standard double glazing is lightweight, reliable, and ideal for everyday use. Non-toughened double glazing offers the same thermal performance as toughened glass but at a lower cost. It is suitable for upper-floor windows and areas where safety glass is not required.
    • Low-E double glazing: Low-E glass offers improved efficiency without compromising appearance. Low-emissivity coatings reflect heat back into the home, helping maintain stable indoor temperatures and reducing energy consumption for enhanced thermal insulation and lower energy bills. This upgrade is especially valuable for properties requiring high EPC ratings or specific levels of thermal performance.
    • Acoustic double glazing: This glazing type is engineered for quieter, more comfortable living. Acoustic glazing uses varying pane thicknesses to disrupt sound waves, significantly reducing noise from traffic, aircraft, and busy urban environments, without compromising thermal performance. This makes it a great choice for bedrooms, home offices, and city properties.
    • Laminated double glazing: This type offers security, acoustic comfort, and UV protection in one solution. Laminated glazing includes an inner layer that improves security and ensures the glass remains intact even when cracked. It also provides strong UV protection, helping reduce fading of furniture, flooring, and fabrics. This makes it an excellent choice for ground-floor living rooms and modern extensions.

    Specialist Heritage and high-performance glazing

    We also specialise in solutions for conservation areas, listed buildings, and properties with narrow frame depths. These glazing options deliver modern performance while preserving traditional aesthetics.

    14mm Slimline double glazing with Krypton gas

    Designed specifically for period sash windows and conservation-approved joinery, slimline krypton-filled glazing allows you to maintain original sightlines without compromising efficiency. They offer strong insulation and reduce condensation, helping you to complete sensitive renovations that bring Heritage homes up to modern standards.

    Fineo & other vacuum glazing options

    Vacuum glazing represents the next generation of energy-efficient performance. With an extremely thin vacuum gap between panes, it offers insulation values comparable to triple glazing, as well as a noticeable reduction in condensation. Suitable for frames as thin as 6–8mm, they are also ideal for historic properties where glass thickness is restricted.

    While vacuum glazing comes at a premium, it is long-lasting and a long-term investment for projects needing the highest levels of efficiency in a very narrow profile.

    U-value comparison

    This short guide helps illustrate the performance differences between glazing types. The lower the number, the better the level of insulation:

    • 24mm Argon (4/16/4): 1.2 – 1.4
    • 24mm Toughened: 1.2 – 1.4
    • 14mm Slimline Krypton: 1.5 – 1.8
    • Low-E (general): 1.1 – 1.4
    • Acoustic: 1.2 – 1.6
    • Laminated: 1.2 – 1.5
    • Vacuum: 0.7 – 0.9
    • Premium Vacuum: 0.4 – 0.5

    Nine Zero can guide you through the technical requirements and recommend the best solution for your project.

    How much will double-glazed windows cost?

    Glazing is always priced according to the level of performance required, the specification of the window system, and the scale of the project. Because every unit is made-to-measure, we offer upfront quotes for every window we produce. Our quotes are completely no-obligation, and will be delivered with a fast turnaround. Contact us with your needs today to get started.

    Working with developers

    We support large-scale projects and complex builds with:

    • High-quality Cornish manufacturing
    • 30-year timber warranties and 10-year glazing guarantees
    • FSC-certified materials and sustainable craftsmanship
    • Collaborative project management built around client timelines
    • Tailored glazing specifications to meet all performance goals
    • Expertise across period, modern, and conservation-area designs

    Get the right glazing for your project

    The right glazing makes all the difference. We can assess your needs, recommend the ideal specification, and ensure your windows perform beautifully for decades. Contact us to book your consultation and let a team member take you through your options today.

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