Secondary glazing prices · 2026
Secondary Glazing Cost Calculator UK
Secondary glazing adds an internal pane while keeping the existing window. It is especially common in period homes, listed buildings and rooms where noise reduction matters, but its pricing should not be confused with a full replacement window.
Quick price answer: Current UK published guides put professionally fitted secondary glazing at roughly £275–£500 per window, with system type, size and number of windows making the biggest difference.
Current price examples
These are practical market or calculator benchmarks, not binding installer quotations. Exact dimensions, specification, access and opening condition can move the final price.
What secondary glazing actually is
Secondary glazing is installed inside the existing frame rather than replacing the whole window. Fixed panels are generally simpler, while sliding and hinged systems cost more because the frames and hardware are more complex.
When it can make sense
It can be attractive when original windows need to remain, when a full replacement is impractical, or when a larger air gap is useful for noise reduction. Bespoke heritage work, unusual shapes and difficult access can increase the price.
Important calculator limitation: the main paid calculator prices complete replacement windows and doors, not secondary glazing. Use the market benchmarks on this page for secondary glazing itself, then use the calculator only if you also want to compare the cost of full replacement.
Related price guides
Compare the closest related costs, then use the calculator for your own specification.
Questions people ask
How much does secondary glazing cost per window?
A sensible current UK benchmark is roughly £300–£500 per professionally fitted window, although some published estimates start closer to £275.
Is secondary glazing cheaper than replacement double glazing?
Often yes because the existing external window and frame remain in place, but the comparison depends on the condition of the original window and the secondary system chosen.
Is secondary glazing good for noise reduction?
It can be. The large air gap between the original window and the secondary pane can improve acoustic performance when the system is well sealed.
Compare secondary glazing with full replacement.
Use this guide for secondary glazing benchmarks, then price a complete replacement window if you want to compare both routes.
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