Secondary Glazing Cost Calculator
Get an instant estimate for your secondary glazing project. Simply enter your window dimensions and preferences to see pricing for all our product options.
Secondary glazing prices explained
This calculator gives a useful starting point, but every period property is different. Window geometry, the required air gap, acoustic glass, access and the condition of the original frame all affect the installed price. Read our secondary glazing cost guide alongside your estimate, then request a survey for a fixed quotation.
How much does secondary glazing cost in London?
In 2026, professionally installed acoustic secondary glazing starts at £675 per small casement (up to 600 × 900mm), £1,220 per standard Victorian sash (up to 900 × 1,500mm) and £2,565 per large Georgian bay (up to 2,400 × 1,800mm). All prices include VAT, a professional survey, 10.8mm acoustic laminated glass, slimline aluminium frames and a 10-year guarantee. Every quote is bespoke to your property, so use these figures as a starting point and book a survey for an exact price.
What is included in the price?
Every installation includes the professional survey, bespoke manufacture to your window's exact dimensions, 10.8mm acoustic laminated glass, powder-coated slimline aluminium frames in your choice of colour, professional fitting — usually completed in a single day — and a 10-year guarantee covering defects, hardware, glass and workmanship.
Are DIY secondary glazing kits cheaper?
DIY magnetic kits cost less upfront, but they are a different product. A typical DIY kit uses a 2–3mm acrylic sheet with magnetic tape fixings, delivers only around 15–20dB of noise reduction and lasts roughly a year. Our professional system uses 10.8mm acoustic laminated glass in engineered aluminium frames, delivers up to 54dB of noise reduction and has a 25+ year service life. Judged over its lifespan, the professional system is the lower-cost option per year of performance.
Does secondary glazing add value beyond noise reduction?
Yes. Secondary glazing reduces heat loss through the window by up to 64%, improving the U-value from 5.0 to 1.8 W/m²K. It may lift an EPC rating by 1–2 bands, depending on the property and the full assessment. It also helps reduce condensation and adds a security layer, without altering the external appearance of the property.
How long does installation take?
Most installations are completed in a single day. The full timeline is around 3–4 weeks from survey to fitting: the survey and quote are provided same-day or within 24 hours, custom manufacturing takes 2–3 weeks, and fitting is typically finished in one day with minimal disruption.
How do I get an exact quote?
Use the calculator above for an instant estimate, then book a free survey. Our installer measures each window, discusses your priorities — noise, warmth and heritage requirements — and provides a detailed written quote on the spot or within 24 hours. No obligation.
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