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Aluminium Secondary Glazing Windows

Secondary Double Glazing Windows

  • 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.

Our range of secondary glazing units

  • Frame
  • Handles

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
  • +
    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
  • +
    2. Weather resistant seals
    • Double seals fitted around the opening window
  • +
    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
  • +
    4. Sliding inserts
    • Cleverly interlock to help prevent draughts into your home
  • +
    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

Secondary glazing FAQs

  • +
    Q. Why would I choose to have secondary glazing fitted?

    Secondary glazing offers you the same benefits of double glazing and is a great solution if you live in a listed building or a conservation area, where replacing windows can be more difficult, but heat loss and rattling can be common problems.

  • +
    Q. What are the benefits of secondary glazing?

    Secondary glazing acts as a form of double glazing by trapping air between the thermally toughened glass and your existing windows, which provides you better heat insulation and lower energy bills. This extra window also provides an additional barrier to help prevent break-ins and can reduce outside noise by up to 12 decibels, which is particularly useful if you live in a noisy environment.

  • +
    Q. Is there a choice of glass with secondary glazing?

    Yes, we offer an extensive range of glass including obscure, decorative, security, and anti-sun, all of which are available to install within your aluminium secondary glazing frame.

  • +
    Q. How much does secondary glazing cost?

    Like all Everest products, secondary glazing is bespoke and made-to-measure specifically for your home and needs. In order to give an accurate price for your windows one of our local consultants will need to view your property and take measurements before providing you with a free no-obligation quote.

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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