Aluminium Secondary Glazing Windows

Secondary glazing

Secondary Glazing

Energy efficiency for listed buildings

  • Unobtrusive design
  • Made-to-measure to reduce draughts
  • Weather resistent seals
  • Reduces external noise

Secondary Glazing From Everest

Secondary glazing is a glazed panel in a frame that is installed to the inside of your existing window. There are different types of secondary glazing, ranging from a DIY plastic-glazed frame that can be clipped to the inside of a window. Or, a glazed unit that is professionally installed. The main reason homeowners install secondary glazing is when they can’t change their windows from the original architectural style of window, usually single glazed. This is either for listed buildings, properties in conservation areas, or to maintain the architectural integrity of the original design.

The gap created between a window and the secondary glazing creates a thermal barrier that has two main benefits. The gap helps the window to reduce heat loss – this is a huge benefit for period properties that struggle to increase their energy efficiency. The gap is also effective at reducing external noise and can be more effective than specialist noise reduction glass.

At Everest, we manufacture and install made-to-measure secondary glazing with an aluminium frame and glass pane. Our secondary glazing is unobtrusive, stylish and the perfect solution for buildings that can’t install double glazing. Everest secondary glazing is available in four styles, horizontal sliding sash, vertical sliding sash, hinged casement sash and fixed sash.

Our Secondary Glazing Units

Everest secondary glazing units are fully glazed for optimal clarity and to avoid the hazy plastic of cheaper units. Frames are made from aluminium for a stylish, slim and unobtrusive unit. We offer horizontal sliding sash, vertical sliding sash, hinged casement sash and fixed sash styles. Everest secondary glazing is made bespoke for you in the UK, with a range of options and colours to choose from.

Secondary glazing design styles

Horizontal Sash

Horizontal Sliding Sash

Vertical Sash

Vertical Sliding Sash


Hinged Casement Sash

Fixed Sash

Fixed Sash

Secondary glazing frame colours

Everest aluminium secondary glazing windows are available in white or brown, with the same tone on the inside and out.

Aluminium colours





Secondary glazing technical sheet

Download a PDF tech sheet for Everest secondary glazing.

Aluminium Secondary Glazing Download

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Commonly Asked Questions

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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.
  • +
    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, reduces draughts and can also be effective at reducing noise pollution.
  • +
    Does secondary glazing reduce noise?
    The robust frames on Everest secondary glazing provides an extra pane of glass and can therefore reduce external noise. This can be particularly useful for properties located near busy roads or airports.
  • +
    Does secondary glazing stop condensation?
    Condensation on the original window will 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.
  • +
    Do I need listed building consent for secondary glazing?
    Secondary glazing can offer 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 can be 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.
A large Tudor style listed house with discreet secondary double glazing on hinged casement windows

The benefits of Secondary Glazing

When you need to retain the original style

If you live in a listed buildings or conservation area, it might not be possible to change your single glazing, so secondary glazing is a great solution for energy efficiency. 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.

Increase energy efficiency

To ensure a perfect fit our Secondary Glazing is made-to-measure, reducing 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

Reduce external noise

Secondary glazing is one of the most efficient ways to reduce noise levels coming into your home. The gap inside double glazing units is 16 or 20mm. Secondary glazing can create a gap of more than 100mm. The wider the distance between your windows and the secondary glazing and the more the sound is reduced.

Secondary Glazing Gallery

Click an image below to open gallery

High-quality Secondary Glazing, guaranteed

  • Aluminium frames are very robust and virtually maintenance-free so your windows stay looking great for many years.
  • Everest Secondary Glazing is fitted with a 10 year guarantee on the whole window and installation.
Secondary glazing windows in the UK

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