Secondary Glazing Explained

What exactly is secondary glazing?

Although they are made of modern materials, secondary glazing isn’t a new concept.

During the Victorian era properties were often built with internal secondary windows as part of the original structure. This was usually another entire sash window with counterbalanced lead weights which were fitted behind the existing external window.

The purpose of these windows were to reduce heat loss as most external sash windows were very draughty. In addition to the thermal benefits, they were also designed to add some protection against the ever increasing road noise.

Extensive Colour Range

Secondary Glazing vs Double Glazing

Whereas secondary glazing is installing an entirely separate window behind the existing one, double glazing involves removing the existing window and replacing the whole thing with a new window. This new window includes two panes of glass installed closely together.

Double glazing is more expensive

Because you’re having to replace an entire window with two panes of glass, double glazing often costs more than installing a secondary pane alongside your existing window.

Secondary glazing is better for noise reduction

The bigger the gap between the two panes of glass, the better the noise insulation. This means that secondary glazing is better than double glazing for reducing outside noise.

The installation process is more unobtrusive

Our secondary glazing is designed to complement the style of your existing windows, but as well as looking unobtrusive, the installation process also causes less disturbance to your everyday life than double glazing. Because we’re adding an additional pane rather than replacing the entire window, secondary glazing can usually be installed with little disturbance to both the building or the inside of your home.

Black Knight Secondary Glazing Limited
Registered in England and Wales Number: 08638414
VAT Registration Number: 197 3861 56

Head Office

Unit 9, Prospect House, Colliery Close, Chesterfield, Derbyshire, S43 3QE

Office Tel

01246 229 000


0808 168 5208