Easiglaze Blog | Tips and Ideas

Double Glazing vs Secondary Glazing

double glazing infographic

Windows provide us with insulation, aesthetic appeal, and protection against the elements among other things. You may be moving into a new house, or you may be trying to change your windows. This article attempts to enlighten you on the type of window finishing you should employ in your home.

Glazing improves the quality of your windows by adding insulation which reduces heat flow through the windows. This insulation reduces the cost of heating in your home or at your office. This helps to maximise the efficiency of the building. Glazing also reduces noise and reduces the amount of water that condenses on your windows. Now, let us talk about secondary and double glazing and their effects.

Why You Should Glaze Your Windows

  • Better Insulation

Glazing improves heat retention by adding a layer of insulation to reduce the amount of heat that is transmitted from the environment. This feature also helps to trap heat during colder periods.

  • Noise Reduction

The movement of sound in materials differs significantly. The sound effect reduces as it moves from solid to gas. Double glazed windows provide a gap or vacuum that takes advantage of this phenomenon. The intensity and speed of sound waves reduce as they move through double glazed windows.

  • Improved Property Value

When done correctly, double glazing can add more aesthetic appeal to your windows. Double glazing also adds to your property’s resale value if you are planning to move. Glazing reduces the amount of sunlight and radiation that enters your house or your office. This can help reduce damage caused by the sun through a process called photodegradation. Photodegradation has harmful effects on your textiles, carpets and even paintings.

What Is Secondary Glazing

secondary glazing

Secondary glazing involves adding another layer of protection to the inside of your window for some or all of the reasons listed above.

This layer of protection can be an aluminium sheet or a sheet of plastic such as polycarbonate plastic. It also involves the addition of another pane of glass to the inner part (of an existing window) of a room or a building. They perform the same duties as a double glazed window. But the extent of their capabilities differ. Secondary glazing can easily be installed if you do not have a building permit for installing double glazed windows.

If you’re on a low budget and you want to keep your windows looking the same, you should opt for secondary glazing.

What Is Double Glazing

double glazing

Double glazing involves using two window panes separated by a gap held by a wooden frame or any suitable plastic material. The purpose of this gap between the window panes is insulation. The gap can be filled with an inert gas such as argon, xenon or krypton. Argon is the least expensive of these three and also the least effective. The gap between the panes can also be a vacuum. The gas-filled gap or vacuum between the windows reduces the heat transfer rate from one side of the glass to the other. Let us take a more in-depth look at these two methods of glazing.

Double Glazing And Secondary Glazing in The UK

Generally, planning permission is required for fixing or installing doubled glazed and secondary glazed windows in the UK. But if your building or house is in a conservation area, you may run into some issues. You should consult your local authority before you install double glazed windows.

Thermal Efficiency

A lot of money is spent on heating and lighting homes and offices. During the winter, more money is spent. This is an essential factor to consider when opting for glazed windows. Double glazed windows can trap nearly twice as much heat as secondary glazed windows. The space in between the sheet significantly reduces the rate of heat transferring from one side of the window to another. Therefore, less energy is required to cool and heat areas. Less money is spent on bills, and you can save more. During the winter, there is minimal heat loss through the windows.

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Secondary glazed windows also provide a level of heat loss minimisation but not as efficient as double glazed windows. The more excellent heat retention of double glazed windows may have some downsides. During summer, the higher heat retention of double glazed windows may cause home and office spaces to be hotter. This can be reduced by tinting double glazed windows, but it costs more.

During the winter, moisture in the atmosphere condenses on the outer surfaces of windows and freezes to form frost. Frost formed outside the window can make the room colder, therefore, making you crank up the heaters.

The presence of moisture promotes the growth of mould and mildew especially in old buildings which raises health concerns. The use of double glazed windows can reduce moisture and stop mould growth. The airtight seal between the panes prevents moisture from accumulating by condensation.

Considering Price

Double glazed windows cost considerably more than secondary glazed windows. More expensive materials are used in producing double glazed windows. Compared to secondary glazed windows, they are made of two panes of glass. The use of the inert gas argon also amps up the price of double glazed windows. All these factors may cause you to think twice before getting those double glazed windows. However, thinking of the long term benefits of double glazed windows make it a good investment.

Another reason why double glazed windows cost more is installation. Double glazing units require the services of a professional installer. Secondary glazed windows are relatively simpler to install. With moderate versatility and excellent handwork, installing secondary glazing units can be a DIY project. This reduces the cost of installation. As easy as installing secondary window glazing may sound, extreme caution should be taken when installing them.


Naturally, the maintenance of windows isn’t a big deal. But when dealing with these types of windows, some considerations should be made for the glazed window.

Secondary glazed windows such as windows glazed with magnetic secondary glazing only require moderate maintenance. The magnetic seals can easily be replaced in case of wear and tear. It has low weight and is cheap. Aluminium secondary glazing can be used for a more effective and aesthetically appealing look. The type of window installed may make maintenance a little less easy.

Double glazed windows cannot be repaired. Once the airtight seal in the window is broken, the whole double glazing unit has to be replaced. They cannot be taken down and repaired.

Generally, windows with double glaze are straightforward to maintain. You can choose between windows that slide horizontally or vertically for easy maintenance.

Noise Reduction

Living on a bustling street or close to the airport can be a headache. Ceaseless noise during the day is not your definition of peace. Which is better at noise reduction, secondary glazing or double glazing? Both types of glazing provide proper protection from noise pollution. The spacing in secondary glazing windows improves the noise reduction potential of the windows. When compared to double glazed windows they have larger spaces between them.

Although there is a limit, generally increasing the gap between the primary and secondary window will improve the acoustic insulation. The key is keeping the space between the secondary glazing and the existing window between 150mm-200mm.

Noise reduction can further be improved by installing sound reducing laminated glass. Also, by adding a second layer of glass with additional thickness, noise can be reduced further. This causes an effect known as the resonating factor which is noise cancellation caused by different wavelengths of sound blocked by layers of varying thickness resonating at different frequencies.


When compared to secondary glazed windows, double glazed windows provide more security. They are sealed much better than secondary glazed windows, thus strengthening security.

What Should You Go For?

Generally, in selecting the type of glazing you want, all the factors above should be thoroughly considered. If you’re concerned about cost, windows with a secondary glaze are considerably cheaper to install. The cost of getting a double glaze is higher, but in the long run, it is a worthwhile investment.

Double glazed windows come with twice as more thermal efficiency than secondary glaze. The improved efficiency saves money on bills and can reduce carbon emissions. On the downside, it may cause your living space to heat up slightly more during those hot summer months. The increased spacing between panes in a secondary glaze will, however, give you better noise reduction. Double glazed windows are more secure with their added toughness and resilience to vandalism.

All these factors considered should guide you in making the right decision. Installing windows with internal double glazing may seem like an expensive and very technical procedure. In reality, it is not.

At Easiglaze, we provide double and triple glazed windows of superior quality. With so much dedication to quality, only the best components are used to manufacture our products. Their thermal and noise/acoustic insulation are outstanding. You can relax in your home which is warmer and quieter than most.

Double-Glazing-vs-Secondary-Glazing infographic

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