Modern performance, original windows

by Jake

Incarnation secondary glazing from Roseview Windows helps owners and architects working on renovation projects get modern levels of thermal and acoustic performance without changing windows.

Renovation and refurbishment projects on historic, heritage and listed buildings can be challenging. They’re often accompanied by complications that come from working on older buildings, combined with rules and regulations stipulating what can—and more often can’t—be done.

Windows are often one of the biggest challenges. They’re a critical part of a building’s fabric and aesthetic, and thus protected by stringent regulations. But at the same time they can be a weak spot in terms of modern expectations covering thermal efficiency, noise abatement and security.

A practical and effective solution is secondary glazing; adding a discreet secondary screen to the interior of a primary window. Set against the internal face of the primary window, secondary glazing will significantly enhance thermal efficiency, improving insulation and cutting draughts and condensation.


But it’s when secondary glazing is set slightly further away from the primary window—a 100mm cavity is ideal—that the benefits really shine through. Not only is thermal efficiency improved even more than with face fit, but acoustic insulation becomes dramatic.

For example, a typical single-glazed original window will offer an acoustic reduction of approximately 25dB. Modern double-glazed windows are more like 35dB. Set against the noise level of a busy road—typically around 75 to 80dB—you’re still left with 40 to 50dB of noise entering the building. That exceeds the World Health Organisation advisory levels for living and office space.

Correctly fitted and sealed secondary glazing, set 100mm from the primary window, can reduce external noise by 45dB. This can be increased further with acoustic glazing. Added to the 25dB reduction from a poor condition primary window, that gives an impressive overall sound reduction of 70dB.


Incarnation secondary glazing is manufactured by Roseview Windows. Established in 1977, Roseview specialises in windows for heritage and renovation projects. They manufacture two suites of products: Incarnation secondary glazing and Rose Collection timber-alternative sash windows.

Roseview has many years’ experience working with homeowners, architects, contractors and conservation officers on sensitive projects. That’s provided a unique insight into what the various interested parties want to achieve and allowed them to design that into their products. That can be seen in the Incarnation secondary glazing suite; it’s simple and cost-effective to install and offers superb thermal and acoustic insulation, while leaving the external appearance of a building untouched.

Along with its thermal, acoustic and heritage credentials, Incarnation secondary glazing features slim, unobtrusive sightlines. It’s simple to operate and is available in a wide range of styles and layouts – designed to allow it to match the transoms and mullions of the primary window it will be used with. It’s versatile too, available with or without timber subframes, allowing it to fit into virtually any window reveal. Finally, as an aluminium product it is both sustainable and highly recyclable.

If you have a refurbishment or renovation project that could benefit from secondary glazing, Roseview’s experience may help solve your window challenges.

For more information about Incarnation secondary glazing call Roseview Windows on 01234 240404 or visit

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