A clearer choice
Both can improve a home. The right answer depends on the original window, the building and what you most want to change.
Use the selector below to bring your priorities into focus, then talk to us about the details of your property.
At a glance
Secondary glazing adds a considered inner layer. Double glazing replaces the existing unit. Here is how that difference plays out in the decisions that matter.
Prioritise what matters
Choose a focus and we’ll bring the most relevant differences to the top.
Secondary glazing
Excellent when specified with acoustic glass and a generous air gap; the second layer helps interrupt traffic and street noise.
Double glazing
Can improve noise, but performance depends heavily on the unit, frame and glass mismatch.
Secondary glazing
Adds a useful insulating layer and reduces draughts while keeping the original window in place.
Double glazing
Usually offers strong whole-window thermal performance when replacing the existing opening is suitable.
Secondary glazing
Often the more sympathetic route because the original external window remains; consent still needs checking.
Double glazing
Replacing original windows can be more difficult in listed buildings and conservation areas.
Secondary glazing
A discreet internal frame preserves the external elevation, original sightlines and existing character.
Double glazing
New frames can change sightlines, proportions and the way a period elevation reads.
Secondary glazing
Fitted inside the room with a practical, measured installation around the existing window.
Double glazing
Usually involves removing and replacing the window, with more work to the opening and finishes.
Secondary glazing
Can be a cost-conscious way to improve performance while retaining the windows you already have.
Double glazing
A larger replacement project, with costs shaped by frame, access, making good and the specification.
Secondary glazing
Designed as an inner layer, it can generally be removed later with the original window intact.
Double glazing
Once original frames are removed, the change is more permanent.
Secondary glazing
The right opening style can retain access to the original window, though the room-side layer needs considering.
Double glazing
Opening behaviour is resolved in the replacement frame, with fewer existing layers to coordinate.
This comparison is a practical guide, not a specification. A measured survey will confirm what works for your property, window and permissions.
The practical next step
Tell us what you have, what you want to improve and what you want to preserve. We’ll help you work out the right route.
