Secondary Glazing

About Our Secondary Glazing Service

Secondary glazing is the addition of a separate, internal glazing panel or frame fitted inside the existing window reveal, independent of the primary window. Unlike replacement double glazing, secondary glazing does not disturb the original window — which is particularly important for properties where the primary window must be retained, either for conservation area or listed building reasons, or simply because it is structurally sound and replacing it is not warranted. The thermal benefits of secondary glazing are substantial. The air gap between the primary window and the secondary panel acts as an insulating layer, reducing heat loss through the window significantly. This makes secondary glazing a cost-effective thermal upgrade for period properties where draughty original sash windows cannot be replaced. It is also highly effective at acoustic attenuation — the second glass layer breaks up sound waves, noticeably reducing road noise, aircraft noise, and similar external sound. At Red Lion Windows, we supply and fit secondary glazing systems in UPVC and aluminium profiles, including horizontal sliding, hinged, and fixed configurations to suit the operation of the primary window. Frames are slim and unobtrusive, and the correct system choice means the secondary panel does not interfere with the primary window's operation. For Boston properties near the town centre, for sash windows in Louth's and Horncastle's conservation streets, and for listed buildings anywhere in Lincolnshire, secondary glazing is often the most appropriate and sensible solution. Contact us for a free survey and to discuss whether secondary glazing is right for your property.