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Secondary Glazing is adding an additional internal window to an existing external window.
This system provides greater thermal insulation, reduces noise intrusion and improves security to your home, business or listed property, without damaging the aesthetics of the original external window
As it doesn’t change the fabric of the building, secondary glazing can be installed within Conservation Areas and Grade I and Grade II Listed Buildings. We often work with HED for design and specification approval before commencing an install.
Secondary glazing is often installed for noise reduction. Acoustic Secondary Glazing can reduce noise levels by up to 80% (equivalent to 54 dB). Standard double glazing typically offers around 30 dB, so the addition of Secondary Glazing will significantly enhance noise reduction beyond simply adding new double glazing.
Draughty windows can make a room feel uncomfortable and lead to higher energy costs as heat escapes. Secondary glazing, with either 4mm, 6mm, or 8.8mm Low E glass, can reduce heat loss by up to 65% and instantly prevent draughts. We often recommend the installation of Low E glass as it has a specifically designed coating that reflects heat back into the room.
Another benefit of secondary glazing is that it offers an increased level of security. If your primary windows are forced open, secondary glazing acts as a second barrier to unwanted entry. Our windows usually come with a lock which helps thwart unwanted guests.
Secondary Glazing NI’s frames are manufactured from durable aluminium and are powder coated, allowing them to stand the test of time. Often used in conjunction with single, double, and triple glazed uPVC or timber windows, secondary glazing boasts unique performance unmatched by any other window system.
The installation of secondary glazing requires a small air cavity which acts as insulation between your primary windows and the secondary glazing. The air cavity plays a vital role when reducing noise levels or increasing thermal efficiency.
Sound – We advise an air cavity of between 150mm to 200mm. This type of installation is referred to as reveal fix. The secondary glazing unit is installed within the window reveal and can reduce noise levels by up to 80% (54 dB). For optimum performance, we often recommend acoustic glass which is available in thicknesses of 6.4mm, 6.8mm and 8.8mm.
Thermal – To achieve optimum thermal efficiency we recommend an air cavity of up to 80mm. This type of installation is commonly known as face fixing as the secondary glazed unit is fixed to the internal face of your primary window. Specified with a Low E glass correctly installed secondary glazing can reduce heat loss by up to 65%.
Our secondary glazing is available in many styles, complementing all window types. We have a range of windows that slide horizontally and vertically for easy access and cleaning.
Our hinged unit operates on a hinged mechanism that can be placed on the side of the window for conventional opening, or on the top or bottom depending on your requirements. Other window styles include fixed windows or lift-outs, which can easily be lifted out of the frame.
We will work with you to offer a range of products that are discreet, functional, and high performing. Our product range is suitable for all window types and can be tailored to meet most budgets.
Secondary Glazing NI’s units are manufactured to order in bespoke sizes and colours. We can bend/arch frames in-house to suit any window size, shape, or style.
As our products are made to order, we can manufacture units that match both transoms and mullions to reduce sightlines and make the secondary glazing even more discreet. For larger windows, typically in commercial applications, we can stack or couple single units to achieve the required coverage.
Our products are manufactured from durable aluminium, and our most popular colour is Standard White (high gloss finish). In addition to Standard White, we offer the following stock colours:
Van Dyke Brown (BS08B29, Gloss)
Cream (RAL9001, Satin)
Grey (RAL7016, Satin)
Ivory (RAL1015, Satin)
Black (RAL9005, Satin)
Traffic White (RAL9016, Matt)
Pure White (RAL9010, Satin)
If you are looking for something more custom, we can also offer 200 additional RAL colours to suit all tastes and preferences.
Secondary glazing is normally specified to combat two main issues: acoustic or thermal performance. In conjunction with the air cavity, the type of glass specified plays a vital role in resolving your issue. As standard, all of our products are manufactured with 4mm toughened glass for enhanced security and safety.
Secondary Glazing NI also provides several options offering enhanced heat and/or acoustic properties.
Sound – Selecting the correct glass and installing the secondary glazed unit with an air cavity of 150mm to 200mm can drastically reduce noise by up to 80% (54 dB). Most traffic noise issues can be solved with the installation of 6.4mm or 6.8mm clear acoustic glass.
Where noise is severe and intrusive, we suggest specifying 8.8mm clear acoustic glass.
Thermal – Cold draughts breaching your primary windows can make a room uncomfortable and increase energy costs as heat escapes. Where thermal performance is required, we recommend the installation of 4mm, 6mm, 6.4mm, or 8.8mm laminate Low E glass. Low E glass has a specially designed coating that reflects heat back into the room, keeping it warm in winter and cool in summer.
We will discuss options specific to your needs; however, we commonly install 6.4mm laminate, which offers excellent acoustic and thermal benefits, while also being a safety glass suitable for many installations.
Secondary glazing can offer value for money by improving the energy efficiency of windows without the need for complete window replacement. It is a cost-effective solution that can lead to significant savings on energy bills over time. The installation process is quicker and easier than replacing windows, and it can be a more sustainable choice, especially for homes in conservation areas or listed buildings.
While the initial cost may be similar to double glazing, the long-term benefits in energy savings and comfort can make it a worthwhile investment. This is especially true given the superior noise and heat performance of secondary glazing compared to traditional PVC double-glazed windows.
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