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Secondary Glazing Windows

Enhance the thermal efficiency in your home with our secondary glazing windows.


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Are your windows causing a draught in your property? Are you unable to upgrade to double glazing? Our secondary glazing windows can offer the perfect solution!

What is Secondary Glazing for Windows?

Secondary glazing for windows is the addition of a second window to your existing window. Homeowners and business owners commonly opt for secondary glazing to offer a discreet, unobstructed solution to insulating windows for listed buildings.

Our Secondary Glazing Windows

We offer a wide range of secondary glazing solutions to property owners, ensuring that you can find the right style to suit most properties. Our range of secondary glazing come in two ranges; Traditional or Heritage.

Horizontal Sliding

Our horizontal sliding windows are an exceptionally popular window due to its multipurpose use. This range is a slim and versatile profile that helps to increase your homes thermal performance while reducing exterior noise by up to 80%.

Vertical Sliding

Vertical sliding windows are designed to match the aesthetics of a traditional box sash window. Help to increase your window security with highly secure locking mechanisms. For homes in harder to reach places for cleaning, a tilt action can be added.


Our hinged casement windows feature a single handle operation combined with a multi point locking mechanism for an enhanced level of security. Being one of the most discreet secondary glazing profiles that we offer, it’s no doubt of its popularity.


Fixed secondary glazing windows act as an independent window that can be installed on the interior of your current window. Its purpose is to reduce significant noise pollution in your home while maintaining a significant level of security and thermal efficiency.

Lift Out

Our lift out secondary glazing windows has a removable panel that allows you to access your window when necessary. The lift out functionality is an intelligent feature for property owners that may require access to the exterior window from time to time.


Here at Granada Aluminium Secondary Glazing, we understand that every home is unique and therefore, your window requirements are likely to be as well. So we can offer a solution to your double glazing needs with our wide collection of specialist glass options.

Benefits of Secondary Glazing

Noise Reduction

Benefit from the most effective home improvement solution to you double glazing needs. With our secondary glazing windows, your home can now significantly outperform standard double glazing. From reducing the noise pollution of traffic too noisy neighbours by up to 80%!

Thermally Efficient

Enhance your homes thermal efficiency with the addition of our secondary windows. Add an extra layer to your existing window and reduce the heat loss in your home by up to 65%. This figure is a staggering 10% more than standard double glazing!

Increased Security

Our windows will provide your home with a discreet secondary security layer. For homes suffering from only one standard window, they may feel as though their property is a higher security risk. So we have designed a solution to enhance the security of your home.

Add Value

Add value to your home with Granada, secondary glazing designed to improve your properties thermal and sound insulation. Just when you thought double glazing was the only option, secondary glazing has provided you with a solution.

Retain Character

Maintain the character of your home with the addition of a slimline window explicitly designed for listed buildings and homes in conservation areas. It used to be hard to find the solution to your double glazing needs, until Granada secondary glazing.

Prevent Condensation

Condensation is a common issue among traditionally glazed properties. However, secondary glazing combined with well balanced ventilation can be the simple and cost effective solution to your condensation prevention needs.

Planning Permission

A common issue among home improvement solutions is the question of planning permission. Do I need planning permission for secondary glazed windows? The answer is usually no. Conservation areas and listed building are two types of properties that especially struggle with double glazing due to the area of the building. However, secondary glazing provides a solution.

Secondary Glazing Windows Prices

Are you interested in receiving secondary glazing for your home or property? Granada Aluminium Secondary Glazing can help. Start your free online quote with us and receive your tailored quote in no time at all. Alternatively, call us on 01909 499 899 and speak to one of our expertly trained team members for all your secondary glazing queries.

Granada Transforms Grade II Listed Church into Quieter, Contemporary Home

Conversion of this Grade II listed former Baptist Church in Cirencester into a contemporary home includes a bespoke secondary glazing package manufactured by Granada Glazing that has increased the building’s thermal and acoustic insulation. Dating back to 1856,...

Granada’s Early Stage Design Delivers Success in Secondary Glazing Projects

Collaboration at early-stage design for secondary glazing specification in all types of commercial and residential projects delivers positive benefits all round, explains Mike Latham from Commercial Sales at Granada Secondary Glazing. Secondary glazing is the proven...

Granada Solves Noise & Thermal Issues in Grade II Listed City Apartments

Acoustic secondary glazing manufactured and supplied by Granada Glazing has created warmer and quieter apartments for residents in Murrays’ Mills, Ancoats, formerly the world’s oldest steam powered cotton mill. Dating back to 1797, the seven-storey Grade II & II*...

Request a Free Secondary Double Glazing Quote – 2 Simple Steps

Secondary Glazing FAQs

What Is Secondary Glazing?

Secondary glazing is a discreet window that is installed in addition to your existing windows. It is installed to the internal side of your property. Available in different styles to suit all window types, secondary double glazing improved noise insulation and thermal efficiency. No other form of glazing can reduce noise levels by up to 80% (which is the equivalent of 54 dB). As it doesn’t change the fabric of the building, secondary glazing can be installed to homes in conservation areas as well as grade I and II listed buildings. Keep the same traditional charm of your original windows with added modern performance benefits. All of Granada Glazing’s products are manufactured from durable aluminium and can be powder coated in over 200 RAL colours. Thanks to the aluminium frame, secondary glazing also offered increased security levels. If your primary windows are forced open, secondary glazing acts as a second barrier as it can’t be opened from the outside. This makes them ideal when used in conjunction with single, double or triple glazed uPVC or timber windows.

Does Secondary Glazing Work?

Yes! Your home will benefit from excellent levels of thermal efficiency and noise reduction when you install our Secondary Glazing. It also acts as a second barrier against unwanted intruders, helping to keep your home safe and secure!

What Are The Types Of Secondary Glazing?

There are six main types of secondary glazing! Our expert team will help you decide which style is best suited to your windows. Lift Out Units - Used when the primary window is fixed, or when the primary window is required to open for ventilation. Hinged Units - These units are used with casement or hinged primary windows. Vertical Sliders - The perfect addition to vertical sliding sash windows. The meeting rails align with the primary window meeting rail. Horizontal Sliders - Used in conjunction with casement or sash primary windows. That requires full access and where the casement window has sufficient space internally to open the secondary glazing. Bespoke - Ideal for more traditional properties, secondary glazing can be installed to unique primary windows. Fixed - Used for an independent window that is fitted internally.

How Effective Is Secondary Glazing?

Secondary Glazing can be a very effective way of enhancing thermal efficiency, security, and noise reduction in your home! The second window acts as a barrier between your UK property and the outside world. Experience a home that is 80% quieter and 65% warmer all year round.

Can you add Secondary Glazing to existing windows?

Yes! The whole design of Secondary Glazing is that it sits in the same window frame as your existing window. The perfect solution to get all the benefits of double glazing without replacing your existing windows!

How Does Secondary Glazing Work?

When installed, secondary glazed windows sit inside the same window frame as your existing window. This acts as a second barrier between your home and the outside helping to improve your homes thermal efficiency, security and reduce noise pollution. This makes it the perfect solution for homes that do not want to completely replace their windows but are looking to make them more efficient.

Why choose Secondary Glazing?

Secondary Glazing is an excellent way of improving the overall performance of your home! It is also a cheaper option than installing double glazing into your home. You can also get Secondary Glazing installed when you live in Listed Buildings and Conservation areas too!

Which Glass Type Should I Choose?

Secondary glazing is usually 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 rectifying your problem. As standard, all of our products are manufactured with 4mm toughened glass for enhanced security and safety. Please be aware that other secondary glazing providers may supply float glass which is brittle and can be easily broken. If broken, it can leave large dangerous shards, often resulting in injury. Here at Granada, we provide several types of glass ranging in thickness to coating. Each type of glass has specifically been designed and selected to offer optimum performance. Selecting the correct glass and installing the secondary glazed unit with an air cavity of 150mm to 200mm, can drastically reduce noise issues by up to 80% (54 dB). Most traffic noise problems can be rectified with the installation of either 6.4mm or 6.8mm clear acoustic glass. Where noise is a real nuisance, and loud, we suggest the specification of 8.8mm clear acoustic glass. Cold draughts breaching your primary windows can make a room feel uncomfortable and makes it uneconomical as the loss of heat will result in higher energy costs. Where thermal performance is required, we advise the installation of either 4mm, 6mm or 8.8mm clear laminate low E glass. Low E glass has a specially designed coating that reflects heat waves into the room, thus keeping your it warm in the winter, and cool in the summer. The type of glass specified can increase or decrease your quoted price. It is best practice to speak with us directly as you may over-specify the glass type. We can provide a tailored solution to rectify your issue, which is both cost-efficient and practical for your specific needs.

What Is The Installation Process For Secondary Glazing?

Secondary glazing is installed to the interior side of the room creating little to no mess. We can often complete installations within 1 hour. We work closely with over 500 national trade installers who will make an appointment to measure and install at your convenience.

What Materials Are Used For The Frames?

As market leaders within the glazing industry, it is essential that our secondary glazing is high performing and aesthetically pleasing. The key to our approach is to use the best raw materials available and manufacture to the highest standard possible. All of our frames are manufactured in house from slimline, durable aluminium. We cut, powder coat, arch and fabricate our aluminium frames in-house under one roof. Utilising high tech machinery such as CNC machines, we can ensure all frames are built to size as sealed units. Our knowledge, expertise and skills in manufacturing ensure high quality and the best performing product. Our competitors have tried to reduce the amount of aluminium within the frames to reduce the cost of raw materials, but we found this has a negative effect on product quality. Granada’s head office holds a team of product developers where they can often be found designing and manufacturing glazing products using new materials and manufacturing techniques. All of our products are quality tested before they leave our facility, ensuring a high level of quality and function.

Will I Lose the Functionality Of My Windows?

Granada’s glazing is available in many styles complimenting all window types. This way, you will still be able to use your original windows all year round. We have a range of windows that slide horizontally and vertically for easy access and cleaning. Our hinged unit operates on a hinge mechanism that can be placed on the side of the window for conventional opening or on the top or bottom dependent upon your requirements. Other window styles include fixed windows or lift outs which can easily be lifted out of the frame.

What is the Difference Between Secondary Glazing and Double Glazing?

Double Glazing is made from two panes of glass which is separated by a sealed air gap, usually filled with a gas like argon, which helps to improve the thermal insulation, sound reduction and overall performance of your home. This helps to improve energy ratings and reductions in carbon dioxide emissions. Building Regulations make double glazing a very recommended, and normally compulsory addition to any new home. Secondary Glazing is an excellent way of improving the overall performance of your home, without the cost of Double Glazing. You can benefit from improved thermal efficiency, security, reduction in noise pollution and energy ratings when you choose to install Secondary Glazing. This is also the best way to improve the performance of older, Listed Buildings or building in Conservation Areas.

What Are The Advantages Of Secondary Glazing?

There are many benefits to secondary glazing! This type of glazing offers the most effective sound insulation, reducing noise levels by up to 80%. Secondary glazing also improves heat insulation and reduces heat loss through the window by around 65%. Secondary window glazing is an excellent value for money.

How Do I Clean my Windows with Secondary Glazing?

To reduce the risk of damaging your secondary glazed windows, here are some useful tips to keep your windows clean and smudge-free! Don't use abrasive cleaning products such as acids or alkalines. Stay away from steel wool or wired scourer pads when cleaning your windows. Make sure to vacuum the bottom track of the horizontal sliding system to avoid dirt build-up.

Does the Secondary Glazing Installation Affect the Existing Window?

No, however, we always use a different thickness of glass in your secondary glazing compared to your existing windows as this will decrease sound reverberation.

Will I Need to Redecorate After my Secondary Glazing is Installed?

No, you won't need to redecorate after secondary glazing is installed! At Granada, our exceptional knowledge allows us to carefully and precisely fit your windows in around 1 hour. Our FENSA approved installers add an extra layer of protection.

How is Secondary Glazing Installed?

Secondary glazing is installed to the interior side of the room, creating little to no mess, and often installations can be completed within 1 hour. Secondary glazing can be installed within the reveal of the window or can be fixed to the face of the primary window, dependent upon the application. To achieve a neat finish, we supply PVC trims as standard, which you can scribe in. To view video tutorials on how to install secondary glazing, please click here.

How do I Measure my windows?

Before you measure your window for the installation of secondary glazing, standard practice is to select a design that compliments your existing primary window. The key is to choose a design that does not add additional site lines and can give you access to your primary window for maintenance, cleaning and ventilation. We ask that all measurements are given in mm and are formatted width x height. Please click here to view a short video which covers all aspects of measuring your windows.

How do I look after Secondary Glazing?

Granada’s secondary glazing is manufactured from aluminium and is powder-coated to give a durable and aesthetically-pleasing finish. From time to time, you may need to wipe the aluminium with a damp cloth to de-dust. Cleaning the glass is no different than any other glass product. As our products are manufactured from high-quality aluminium, they are self-sustaining, giving many years of trouble-free service. In the unlikely event of a malfunction, please speak with either the tradesman who installed the secondary glazing or talk with our after-sales care team who you can contact on 01909 499 899.

What Depth of Air Gap is Best for my Windows?

The installation of secondary glazing boasts many unique benefits. One of these benefits includes an 80% reduction in sound (54 dB) and a 65% decrease in heat loss. 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. (We advise a different air cavity based upon the issue you are trying to cure.) 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, Granada recommends the specification of clear 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%. Please speak with Granada directly, where we will be able to recommend a solution, tailored to your requirements.

Does Secondary Glazing Enhance the Security of my Home?

As secondary glazing can’t be opened from the outside, it adds an extra barrier to forced entry. If an intruder forces or breaks the glass of your primary windows, they will have to try and force the secondary glazing to gain access to your property. Secondary glazing is a popular choice for homeowners who live in a conservation area or Grade I and Grade II listed buildings. Secondary glazing can be installed without planning permission and prevent the issues old windows have which can’t be changed. Historic England recommends the installation of secondary glazing as it does not change the original fabric of the building. For homeowners that can change their original timber windows but don’t want to lose the character of their property, secondary glazing which is discreet in style and design is an option which is often specified.

What is the Benefit of the Subframe?

All of Granada glazing’s products are manufactured and supplied with a timber subframe (please note: insert panels are not supplied with a subframe). As standard, the wooden subframe and aluminium window frame are pre-drilled and countersunk for ease of installation. The hardwood subframe which surrounds the secondary glazing unit increases the rigidity of the whole window, aiding installation. As aluminium is a great heat conductor, the wooden subframe acts as a thermal barrier which prevents cold bridging from the fabric of the building onto the aluminium. In turn, this can help reduce condensation, as the temperature of the building fabric does not cool the temperature of the aluminium frame and glass. As standard, (on most products) we supply aluminium secondary glazing with a subframe, pre-drilled and countersunk. As we manufacture in-house, we can provide secondary glazing to your specification. Please advise at the point of quotation if you do not require a subframe or pre-drilled units.

How does Secondary Glazing Increase Security?

As secondary glazing can’t be opened from the outside, it adds an extra safety barrier to forced entry. If an intruder forces or breaks the glass of your primary windows, they will have to try and force the secondary glazing to gain access to your property. All of our secondary glazed products are manufactured from durable aluminium where toughened, security glasses are available to offer extra protection.

Does Granada Install Secondary Glazing?

Granada Glazing designs and manufactures bespoke aluminium secondary glazing. Our products are widely used within both homeowner and commercial markets. We have partnered with over 500 industry-leading tradespeople who install our products for homeowners. Our elite trade network installs secondary glazing products throughout the whole of the UK. We often receive homeowner/residential orders where these are passed to a local tradesman who will survey and install our products. Our approved trade network is trained to the highest standards and adhere to Granada’s customer care guidelines. At Granada, we pride ourselves on the quality of our product, which is matched by high levels of service given by both our approved tradesman and our internal sales team. Since 1984 Granada Glazing has been the industry leader. We offer technical support and can recommend a product that is suitable for most budget requirements, performance and functionality. For technical support, or help with selecting the right product to cure your noise or thermal issue, please speak with us directly by telephoning 01909 499 899, or click here to email our internal technical support team. For commercial installations, Granada has an in house surveying and installation team. We have designed, manufactured and installed secondary glazing within some of the most iconic buildings situated in England, Scotland, Wales and Ireland. Notable projects include: • Bush House – London • Edinburgh Castle – Scotland • Stirling Castle – Scotland • Parkinson Building – Leeds • Gradbach Mill – Derbyshire • Great Northern Hotel – London

Are there any Guarantees or Warranties?

In the unlikely event of a malfunction, our secondary glazing is backed up with a five-year warranty on frames and glazing; and a two-year warranty no moving parts. The majority of our elite trade network are members of FENSA. FENSA is a governing body where tradespeople and installers can self certify that their installations comply with current building regulations. In the unfortunate event of a malfunction, please speak with our customer care team by telephoning 01909 499 899.

Will Secondary Glazing work with Double and Triple Glazing?

Secondary glazing can be used in conjunction with all types of windows. Traditionally, secondary glazing was utilised to increase the thermal properties of single glazed timber windows. Modern advancements in specific glass types and frame material have given secondary glazing a new lease of life. Its acoustic performance is unmatched by any other glazing product and can drastically reduce noise breaching single, double and even triple glazing. If you live in an area with high noise pollution, only secondary glazing will reduce noise levels by up to 54 dB, turning the sound of a diesel bus into a whisper. Manufactured from durable aluminium, Granada’s secondary glazing is slimline and can be powder coated in over 200 RAL colours to suit all tastes and preferences. Slimline by nature and durable by design, Granada’s secondary glazing will enhance the thermal and acoustic performance of your windows, while standing the test of time.

Can you Install Secondary Glazing yourself?

A skilled tradesperson can install secondary glazing within 1 hour. Our products are supplied as standard with a hardwood subframe. The subframe serves two purposes; It enhances the rigidity of the aluminium window for ease of installation and acts as a thermal barrier between the fabric of the building and aluminium window frame. Installation and finishing videos can be viewed by clicking here.

What is DIY Secondary Glazing?

Secondary DIY Glazing kits are available in a wide range of colours and styles. You can use these kits, which accommodate any size window, and can be installed in less than an hour.

Can you Choose the Colours of Secondary Glazing?

Our Secondary Glazing comes in a range of bespoke and RAL colours. This means our Secondary Glazing can be the perfect addition, which can suit your home perfectly.

What Colours are the Secondary Glazing frames available in?

You can choose from a range of RAL colours, and bespoke colours when you choose our Secondary Glazing! This means we guarantee we have the perfect addition for your home!

What Colours are the Frames Available in?

Our products are manufactured from durable aluminium and powder coated in house. Our standard, and most popular colour is Standard White with a high gloss finish. In addition to standard white, we hold stock colours which include: 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) To offer our customers short lead times Granada purchased a powder coating line allowing us to finish all products in house. This investment has given our customers a level of customisation as we can powder coat frames in over 200 RAL Colours to suit all taste and preferences.

What is Fixed Secondary Glazing?

Fixed Secondary Glazing is an independent window that is fitted onto the internal side of your existing window frame. This creates a second barrier between your home and the outside, helping to enhance noise reduction, thermal efficiency and security of your home.

Why add Fixed Secondary Glazing into your home?

When you install Fixed Secondary Glazing into your home, you get an elegant, slimline addition for your property. The external appearance of your home is not altered, but the internal aesthetics are greatly enhanced. The performance of your home is too!

Can I add Fixed Secondary Glazing to a Fire Escape Window?

No, a Fixed Secondary Glazing panel means you cannot have access to the original, existing window. This means that you cannot installed Fixed Secondary Glazing panels to your designated fire escape. This would also not comply with Building Regulations.