What is Secondary Glazing?
Secondary glazing is installing an extra window made of aluminium profile with different glass options (Low E glass, Laminated, acoustic, toughened and obscure glass) inside of your existing or old windows. It is a second made-to-measure window which is attached with your existing window.
Secondary Glazing can be installed to any type window whether it is double or single glazed.
For more information view our guide of seconadry glazing.
What makes Colin’s secondary glazing unique?
🟢 High quality Aluminium Frames
🟢 Toughened Laminated Glass
🟢 Better security
🟢 Made in UK
🟢 Certified insulation of heat and noise
Why Do You Need Secondary Glazing?
Secondary Glazing in a listed building
If you live in a listed building or in some conservation areas your local authority probably won’t allow the outside look of the building to be changed. In this case you need secondary glazing.
So, If you are living in the listed buildings or heritage homes and want to have insulated windows with thermal efficiency and security but you can’t replace your windows with double glazed windows like uPVC sliding sash windows, then our secondary glazing is a best alternative option available in the UK.
After installing our secondary glazing units you will have the following benefits at your place.
65% less heat loss
80% noise reduction
Gorilla level Security
Lower Condensation
Increase energy efficiency
Our Range of Options For Secondary Glazing
At Colin’s Sash Windows we offer the following range of secondary glazing for all types of windows.
Horizontal Sliders
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- Horizontal sliders secondary glazing
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- Horizontal sliders secondary glazing
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- Horizontal sliders secondary glazing
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- Two Pane
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- Three Pane
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- Four Pane
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- Five Pane
Our horizontal sliding secondary glazing is a popular, versatile choice that works well with most window types. These slim units make it easy to open your windows for cleaning and fresh air.
Click to view PDF
Click to view PDF
Click to view PDF
Click to view PDF
Prices of Horizontal sliding secondary glazing starts from £175 / Window
Vertical Sliders
Prices of vertical sliders secondary glazing starts from £175 / Window
If you can’t replace your old single glazed sash windows with modern double glazing—especially in listed or heritage buildings—our secondary glazing for vertical sliding sash windows is the perfect alternative.
Our secondary glazing fits neatly inside your existing sash windows, so you can keep the original look from the outside.It adds an extra layer of security because the units can be locked.
Even if you’re in a newer property, our sash window secondary glazing is a brilliant way to bring in that classic, vintage style. You’ll also enjoy up to 80% noise reduction and 65% better heat insulation, so your home stays quieter and cosier all year round.
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Our Available Units in Vertical Slider Secondary Glazing
Balanced Vertical Sliders Secondary Glazing Unit
Tilt-in Vertical Sliders Secondary Glazing Unit
Side Hinged
Prices of side hinged secondary glazing starts from £175 / window
If you are exploring your options and want to plan your budget, our secondary glazing cost calculator can help you estimate the overall price based on your window sizes and chosen specifications.
Our hinged secondary glazing is a flexible option that works with most window styles, including casement and traditional box sash windows. You can choose which side the panels open from, or even have them hinged at the top to suit your space.
For extra soundproofing, you can select single or double-glazed glass. All units come with a secure multi-point locking system, helping to keep your home safe, warm, and quiet—with up to 80% noise reduction and 65% better heat insulation.
These slim, unobtrusive panels don’t block your view and are easy to open for cleaning. Whether you’re in a modern home or a heritage property, hinged secondary glazing is a simple, practical way to improve comfort without changing the look of your windows.
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- Side Hinged
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- Side Hinged
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- Side Hinged
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- Side Hinged
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Our Available Units in Side Hinged Secondary Glazing
Please click on the image below to view detailed PDF brochure on each unit
Spot the difference, we bet you won’t
Retain Original look of Your Windows
Our secondary double glazing is designed to be discreet. Once it’s fitted inside your existing windows, you’ll still keep the original look of your windows while enjoying many of the same benefits as standard double glazing.
We know you are curious about how secondary glazing will look after installing but believe us you’ll find it barely noticeable unless you deliberately search for it.
⬅️ Let us know if you spot the difference in the before and after secondary glazing image.
More Temperature Efficiency
Our secondary double glazing system helps in reducing the heating bills and maintaining the cozy temperature of your home which results in the reduced energy consumption and lower carbon emissions.
Colin’s sash windows secondary glazing system is thermal efficient and can be further enhanced by utilising Pilkington K or Low E glazing. Once the secondary glazing will be installed your home windows thermal efficiency will increase up to 60% to 70%.
Our secondary glazing system is test certified which shows that your single glazed window thermal insulation will become more efficient by as much as 65% or the U-value of 1.868 W/m2K (High performance ) while the standard single glazed windows U-value is approximately 5.8 W/m2K (Quite Poor) which is much higher.
Reduced Noise
With our secondary glazing we can’t tell exactly how much noise will be reduced as it depends upon the behavior and sense of noise pollution of the customer, but according to the noise pollution test of our secondary glazing if you choose the right glass and specification then you can reduce the external noise up to 80% or by over 50 decibels which is a good number.
If your space or area allows then you can leave the gap of at least optimum of 150mm to 200mm between your secondary glazing and your existing window for maximum air gap because the larger the gap will be the more outside noise will be eliminated.
If you have not enough space to leave the gap then we recommend you to at least choose thick glass, especially acoustic with 6mm thickness to get the maximum noise cancellation.
Further, when you enquire about your secondary glazing from us then our advisor will guide you to choose the best glass options for best performance.
Gorilla Level Security
Our secondary glazing not only reduce noise and increase thermal insulation but also help in setting the Gorilla level security because windows can be an easy way to breach the security for thieves and break into the house or building so our extra discreet and unobtrusively secondary glazing to your existing windows can make it difficult for intruders to break into your house as they have to breach this extra more stronger layer.
With the more advanced locking options and laminated and thickest toughened glass can even increase the security to ultra level and we call it “GODZILLA SECURITY”. We recommend installing our secondary glazing especially in listed buildings and heritage homes.
Why is our secondary double
glazing the best?
Discreet and unobtrusively profiles
Our secondary glazing is designed to be discreet and unobtrusive which keeps your original windows look and style unaffected.
Sleek Look Aluminium
Frames
Our aluminium secondary glazing comes with the slim and sleek look aluminium frames which are both modern and elegant and lasts long.
Range of glazing
options
We offer a wide range of glass options Low E glass, laminated and toughened glass for better thermal insulation and noise reduction performance.
11 Years in Market
Colin’s Sash Windows has been in the market since 2014 and served thousands of happy customers which makes us different from other sellers.
Made to Measure
All our secondary glazing systems are made to measure to perfectly fit inside your existing windows. You can go through our measuring guide before placing an order to us.
Expert Advice
When you will be doing the business with us our expert advisors will understand your needs and requirements and help you in choosing the best options for your secondary glazing.
Calculate the Cost of Secondary Glazing
Get a fast, accurate estimate of Secondary Glazing in just 60 seconds using our secondary glazing cost calculator. No sign-up, no obligation – simply enter your details and see your tailored price.
Secondary Glazing Helpful Guides
Frequently Asked Questions
We know that glass plays a major role in sound-proofing and thermal insulation which is why we have a range of glass options for our secondary glazing available to choose from that perfectly meets your needs.
The standard glass is 4mm thick which is the minimum requirement for customers whose building regulations require health and safety.
Important Note: All glass options which we are giving conform to BS6206: 1981 / BS EN 12600 for impact resistance and we do not offer non-safety glass.
Low-E glass
Low E Glass also known as Low-emissivity glass reflects heat back and prevents it from coming into your room for better thermal efficiency.
Toughened glass
We have the various options available in toughened glass 4mm, 6mm and obscure toughened glass.
4mm toughened glass is a standard option which is suitable if your primary window is double glazed and your building regulations demand health and safety. It can give a thermal efficiency of 50%+ and with the right air-gap 45dB noise cancellation.
6mm toughened glass is the same but with 50% extra material and it also gives the 50%+ thermal insulation efficiency and 49dB+ sound reduction which is more than the 4mm glass and this glass is 2-4 times stronger than an ordinary glass of same thickness.
Obscure toughened glass is a privacy glass available in both 4mm and 6mm thickness, if you are planning to install the secondary glazing in the bathrooms or in the area which requires privacy then you can have this option with same benefits there are two designs available in obscure Stippolyte and Satin.
Laminated glass
We have 4 options for our laminated glass, you can choose from them based on your needs.
6.4 mm clear Laminated is considered as a class B security (2BC) and it helps in reducing noise at enhanced level. It has a 0.4mm transparent sheet of ethylene-vinyl acetate (EVA) between the glass.
6.4 mm clear acoustic is also considered as a class B security (2BC) but as it comprises PolyVinyl Butyral (PVB) interlayer so it offers optimum noise cancellation from 51db to 53db.
6.8 mm clear laminated is considered to be a Class A security glass giving the maximum security and noise reduction. It has a 0.8mm transparent sheet of ethylene-vinyl acetate (EVA) between the glass.
6.8 mm clear acoustic is also considered as a class A security glass as it also comprises PolyVinyl Butyral (PVB) interlayer which absorbs sound energy and gives the maximum noise cancellation performance of 51db to 53db.
Note: As acoustic glass is the premium product so we quote the price for them when you get a personalised quote from us.
Our Recommendation:
As we have already described above that the right air gap which is at least 150mm to 200mm between primary and secondary glass is the major factor of reduced sound if you can manage to have this gap then a 6mm standard laminated can be the best option to achieve the optimum sound proofing you don’t have to go with the costly options which is acoustic glass, if the budget is the problem then please don’t go with the lower cost system just to have the acoustic version but if the gap is not possible between primary and secondary glazing then of course you have to go with the acoustic glass.
Basically our secondary glazing system is mostly for the DIY market because we deliver the ready to fit frames which can be easily installed.
After reading our step by step installation guide you can easily position and level your secondary glazing frame in the place of installation and then apply our finishing trims which we will supply along with your secondary glazed windows to avoid any inaccuracies and gaps between wall and frame to perfectly fit it.
If you can’t DIY then you can also take help from your neighbour or any family member who knows how to fix the screws etc. On the other hand you can also find and contact a local carpenter or installer to help you install your secondary glazing. We can also install in various areas.
To get a perfectly fit size for your secondary glazing it is important that you should read our measuring guide before placing an order to us
Following are the PDF of our measuring guides
📄 Measuring guide for secondary glazing.
