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Secondary Glazing - The Clear Choice

Secondary glazing has stood the test of time and remains the best form of insulation for houses, offices, public and private sector buildings against heat loss, draughts and noise intrusion.

The Benefits

✓  Up to 45dB reduction in sound penetration

✓  Low-E glass available to help reduce heat loss

  Acoustic glass available to help reduce noise pollution

✓  Reduced energy consumption in winter and summer

✓  Keep cool air in when using fans or air conditioning

  Sleek designs to fit seamlessly with any intetior

  Quick and easy installation

  Easy to care for, clean and maintain

Easy installation with no mess

All windows in our range are aestecially designed to integrate seamlessly with your existing décor and are available in a full range of colours.


A number of window designs are available to choose from to suit existing window and door styles:

  • Fixed

  • Hinged

  • Lift-Out

  • Horizontal Sliding

  • Friction & Counter balanced vertical sliding

  • Easy Clean Tilt-in Counter balanced vertical sliding


The Technical Stuff

The sound and heat energy benefits of secondary glazing explained in detail.


'U Value' explained

U value is a means of comparing the heat lost through various parts of a building. A part of a building with a U value of 4.0W/m²K will lose twice as much heat as one with a U value of 2.0W/m²K.

The lower the U value, the less heat you will lose

A single glazed window has a U value of 5.6; With secondary glazing, this could be reduced to 1.8-1.9.

Low-E glass in secondary glazing reflects most of the heat back into the room.


Eliminating Draughts

Draughty windows can create cold spots throughout a room, particularly around the legs and feet. As a result of this, heating is usually turned up higher to compensate.

The tight tolerances designed into our secondary glazing system keep cod air out, whilst retaining the warm air in the building.

Air Permeability Test

This defines the ability of the window to resist air penetration when it is subjected to differential pressure and is a measure of the air which seeps through the test window at the given test pressures.

The secondary met the stringent test results of Pressure Class 300Pa, and was tested by BSI to the following standards:

  • BS 5368: Part 1

  • BS 6375: Part 1


Extensive use is made of air-conditioning in today's busy offices, shops and at home.

Installing secondary glazing will help to reduce the energy used in cooling the building and prevents cool air escaping through your windows.


Sound Reduction

Sound is described in different ways, but primarily in terms of intensity and frequency.

The intensity of a sound is measured in dB (Decibels). A low dB indicates a soft sound and a high dB value indicates a loud one.

Frequency describes how high or low pitched a sound is, and is measured in Hz (Hertz).

Test Results

At the Building Research Establishment in Watford, a primary window with 4mm thick glass was tested with our secondary glazing installed, and achieved the following results.

The existing window achieved a reduction of 26dB.

The secondary glazing, installed with a 100mm air cavity between, achieved the following results:

Estimated reduction in sound through the window.

  • 4mm glass  (39dB) was reduced by 65%

  • 6mm glass  (39dB) was reduced by 65%

  • Laminated  (40dB) was reduced by 70%

  • Acoustic (45dB) was reduced by 75%

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