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Aluminium Secondary Glazing Windows

Secondary Glazing

  • Perfect for listed buildings
  • Unobtrusive design
  • Made-to-measure to reduce draughts
  • Weather resistent seals
  • Reduces outside noise
Close up of Everest white secondary glazing

What is Secondary Glazing?

Secondary Glazing is the addition of a slim second window to an existing window. It is a discreet and unobtrusive method of insulating and soundproofing windows. It is also a popular solution in areas that have restrictions on the installation of double glazed windows such as listed buildings.

Secondary Glazing Gallery

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The benefits of Secondary Glazing

A large Tudor style listed house with discreet secondary double glazing on hinged casement windows

Retain your original style

Secondary glazing for listed buildings or conservation areas is a great solution as replacing windows can be more difficult. The slim aluminium secondary frame is unobtrusive and almost invisible from the outside, blending seamlessly into your home to retain the external character of your property.

Eliminate cold draughts

To ensure a perfect fit our Secondary Glazing is made-to-measure, eliminating draughts or rattles from your old elegant windows. The thermally toughened secondary glass acts as a form of double glazing by trapping air between itself and the existing window, providing extra insulation to keep your home warmer and energy bills down. All in all secondary glazing costs you less and makes your home more cosy.

A traditionally styled window with white aluminium horizontal secondary glazing
Secondary windows with two locking points for added home security

Keep your home safe and quiet

The extremely robust frames on our secondary windows firmly close with two locking points to provide additional home security against forced entry. This extra pane of glass has also been tested to reduce noise pollution from outside which is particularly useful if you live near a busy road or an airport. Overall not only does secondary double glazing cost you less for installation it also helps you to make your home more secure and noise proof.

Guaranteed for peace of mind


Aluminium is so robust it will never rot, rust or flake making it virtually maintenance free. Secondary glazing is also our first ever product, when we started way back in 1965, which means we've been manufacturing it longer than any of our competitors.

Secondary Glazing FAQs

At Everest, we understand that choosing new windows can be a daunting task. So to help you here are some frequently asked questions which you might find useful.

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    Is secondary glazing the same as double glazing?
    No secondary glazing is very different to double glazing. Secondary Glazing is the application of a separate thin frame with a single glazed pane of glass in the window aperture. It's a very effective way of improving the performance of an original single glazed window which is letting in draughts but is not suitable to change either for access reasons or because you love the design of your old windows and you don't want them replaced.
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    Does secondary glazing work?
    Yes secondary glazing is very effective by creating a large air gap between the old window and the room. In addition its less expensive and easier to install than replacement windows. Secondary glazing helps with heat retention, eliminates draughts and is also effective at reducing noise pollution.

    Read more: Why should I consider secondary glazing...
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    Does secondary glazing reduce noise?
    Secondary glazing can reduce external noise pollution by up to 80%. The robust frames on Everest secondary glazing provides an extra pane of glass tested to reduce external noise. This can be particularly useful for properties located near busy roads or airports.

    Read more: What are the benefits of secondary glazing...
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    Does secondary glazing stop condensation?
    Condensation on the original window will certainly be expected to reduce as the addition of the secondary glazing will reduce the levels of humidity on the old window. This is because the new pane creates a very effective break from any moisture in your home forming on your old window.

    Read more: What are the benefits of secondary glazing...
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    Do I need listed building consent for secondary glazing?
    Secondary glazing offers a perfect solution, as it does not damage or alter the original windows and is fitted inside the home. Also as it is easy to remove without damaging the fabric of the building most planning authorities see it as an acceptable upgrade to a building. However, if you want to be certain it is always advisable to consult your local planning advisers.

    Read more: Do you need planning permission for windows...
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    What is secondary glazing for sash windows?
    Secondary glazing for sash windows is a perfect option if you live in a conservation area or listed building. These often comprise of a vertical sliding unit fitted on the inside of a sliding sash window. The secondary glazing will sit discreetly inside the window, helping to improve energy efficiency, without impacting the façade of the property.

Our range of secondary glazing units

Secondary glazing frames

Frame colours:




Frame styles:


Vertical Sash

Vertical Sash

Horizontal Sash

Horizontal Sash

Secondary glazing handles

Handle colours:








Handle styles:
AF Handle

Modern Handle

Technical Specifications of the secondary glazing system

Everest aluminium secondary glazing
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    1. Glazing
    • Air gap created between existing window and secondary glazing panel for increased heat and sound insulation
    • BS EN 12150 - 1:2000 thermally toughened safety glass
    • Optional 6.4mm laminated glass for increased security
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    2. Weather resistant seals
    • Double seals fitted around the opening window
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    3. Locking mechanism
    • Sliding windows fitted with sprung catch locks that automatically fasten as the window is closed
    • Lockable handles and security bolts on hinged windows
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    4. Sliding inserts
    • Cleverly interlock to help prevent draughts into your home
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    5. Aluminium frame
    • Aluminium internal double glazing is low maintenance and will never rot, rust or flake
    • Slim design hardly noticeable from outside, retaining the external character of property

Everest's latest customer window reviews

5 star review for garage doors
I was very pleased with the 15 double glazed secondary windows that I requested to be installed. The process was efficient and faultless and the workmen left the property clean and tidy. I would be very pleased to recommend this company in the future. Shelia Pawson 23/6/18

Windows advice and inspiration

Read our expert advice from inspiring ideas and useful information to maintenance and tips for caring for your windows.

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