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    What is Secondary Glazing for Sash Windows?

    What is Secondary Glazing for Sash Windows?

    Secondary glazing brings the benefits of modern, efficient, double-glazed windows to your home without the need to replace your existing windows.

    By adding a second pane of aluminium-framed glass inside your existing windows, secondary glazing helps keep the heat in and the noise out. As a result, by fitting secondary glazing you could save around 10% on your household heating bills while making your home environment more comfortable.

    Because secondary glazing leaves your existing windows untouched and intact, it’s particularly suitable for use in conservation areas and listed buildings. It’s great in any building where altering or replacing the primary windows is not possible or not cost-effective, making it ideal for rented accommodation. And even if you already have double-glazed windows, adding secondary will further improve noise reduction and heat retention.

    Our aluminium secondary glazing is of the highest quality, lightweight, highly effective and comes with the option of a range of specialist glass for maximum noise reduction and thermal performance. Built to last, it’s virtually maintenance-free and will give you many years of trouble-free service.

    Ventrolla secondary glazing comes in white, silver or brown as standard, or any of 200 RAL colours on request. Aluminium is strong and durable, which means the frames can be designed to be slim without sacrificing strength, so that they blend in to the existing windows.


    • Available in white, silver, brown or any RAL colour
    • Float, obscure, toughened, laminated, ‘K’ and acoustic glass options
    • Made-to-measure
    • Face fix or reveal fix options
    • Easy to install
    • Can incorporate fly-screens for summer

    Benefits of Secondary

    • Improved thermal insulation
    • Saves money on heating bills
    • Highly effective for noise insulation
    • Provides added security
    • Retains exterior character of your building
    • Perfect for conservation properties where alterations are restricted

    Available in a wide range of designs

    • Vertical Sliding
    • Ideal for traditional sash windows
    • Optional spring balances to support open sashes in position
    • Optional tilt-back facility
    • Wide range of frame options available

    Horizontal Sliding

    • Ideal for casement and ribbon windows
    • Smooth sliding action using nylon pads or roller wheels
    • Triple track option for maximum ventilation
    • Wide range of frame options available

    Hinged Units

    • Suitable for both windows and doors
    • Friction or butt hinged, according to requirements
    • Perfect for fire escapes
    • Ideal for maximum ventilation
    • Wide range of frame options available

    Lift Outs and Fixed Units

    • Perfect for shaped windows
    • Useful for situations where access to the external windows isn’t paramount
    • Ideal for bay windows and other specialist applications
    • Highly cost effective

    Noise Reduction

    Secondary glazing is recognised to be the most effective type of glazing when it comes to reducing noise through windows. Noise from traffic, aircraft and general noise from towns, cities and main roads can be a real disruption to the quality of your living or working environment. Installing secondary glazing is a cost-effective way to significantly reduce this problem. Standard 4mm float glass provides effective noise insulation, by upgrading to thicker (6mm+) laminated or acoustic glass, noise reduction can be enhanced even further.

    Thermal Insulation

    Adding an extra pane of glass to your existing windows can dramatically decrease heat-loss, which is why our secondary glazing can reduce heat-loss through the windows in your home or office by up to 50%. Standard float or toughened glass performs very well at reducing heat-loss, by upgrading to Pilkington ‘K’ low-e glass will improve thermal performance even more.

    The low-down on U-values

    What do we mean by U-values? U-value is a means of comparing the heat lost through various parts of a building. For instance, a part of a building with a U-value of 4 W/m2K will lose twice as much heat to the outside as a part with a U-value of 2 W/m2K.
    The lower the U-value, the less heat you lose through your windows.