Secondary Glazing LondonAcoustic & Thermal Windows for Listed and Period Homes

Secondary Glazing Windows Across London

London's period housing stock — much of it listed or within conservation areas — presents a unique challenge: how to escape the roar of city traffic, railways and flight paths while keeping the character of original single-glazed windows. Replacement double glazing is rarely permitted and often destroys historic fabric. Secondary glazing is the answer, and it is what we do exclusively.

Our bespoke internal units sit discreetly behind your existing windows, delivering modern acoustic and thermal performance while remaining fully reversible. Explore our complete secondary glazing guide or jump straight to the solution you need below.

London Noise: The Capital's Biggest Glazing Challenge

No other UK city puts windows under the strain that London does. Red-route arterial roads such as the A40, A4 and Euston Road carry traffic around the clock; the Underground and overground rail network sends low-frequency rumble through entire terraces; and homes beneath the Heathrow and City Airport flight paths contend with aircraft noise that peaks well above comfortable levels. Single-glazed sash windows — the standard across the capital's Georgian and Victorian housing — offer almost no defence, typically blocking little more than 25dB.

This is where secondary glazing outperforms even modern replacement double glazing. By fitting a fully independent internal window with a wide 100–150mm air gap and 10.8mm acoustic laminate glass, we decouple the two panes so sound waves cannot pass straight through. The result is up to 54dB of noise reduction — enough to turn a room facing a busy London junction into a genuinely quiet space. For homes near stations or flight paths, our acoustic noise reduction glazing is the single most effective upgrade available.

Conservation Areas & Listed Buildings Across London

More than a thousand conservation areas cover London, and tens of thousands of properties carry Grade I, Grade II* or Grade II listings. From the stucco terraces of Kensington and Chelsea to the Georgian squares of Islington and the maritime townscape of Greenwich, planning rules protect the original windows that define these streets. Replacing them with uPVC or aluminium double glazing is almost always refused — and can trigger enforcement action.

Because secondary glazing is installed entirely inside the room and can be removed without leaving a trace, it is classed as a reversible alteration and rarely requires listed building consent. We liaise directly with borough conservation officers, match frame finishes to your existing joinery, and align our slim meeting rails with your original sashes so the system all but disappears. It is the compliant route to a warmer, quieter home — explained fully in our guide to secondary glazing for listed buildings.

Choosing Secondary Glazing Installers in London

There are dozens of secondary glazing companies in London, from national manufacturers to one-person fitting firms. Quality varies widely, so before you accept a quote, check the installer against these points:

• Survey in person. A reliable installer measures every opening on site and checks reveal depth, sill condition and how the original windows open. Quotes from photos alone often change after fitting starts.
• Glass specification in writing. The quote should name the glass (for example 6.4mm laminate or 10.8mm acoustic laminate), the air gap and the frame system, not just "acoustic glass".
• Heritage experience. For listed buildings and conservation areas, ask for examples of past projects and whether they will help with listed building consent.
• Guarantees and insurance. Look for a written guarantee on frames, glass and workmanship, and confirm the firm carries public liability insurance. We guarantee every installation for 12 years on parts and labour.
• Fire escape and ventilation. Upstairs escape windows must stay openable. A good installer will raise this without being asked.
• Clear itemised pricing. Compare quotes per window, including survey, fitting, making good and disposal, so you are comparing like with like.

For a fuller checklist, read our guide on how to compare secondary glazing companies, and see the building regulations for secondary glazing.

Secondary Glazing Services in London

Secondary Glazing by London Borough

We have local teams and completed projects across London. Find dedicated information for your area:

Browse all London boroughs we serve →

Why London Homeowners Choose Us

As London's specialist secondary glazing company, we combine heritage sensitivity with modern engineering. Our 10.8mm acoustic laminate glass achieves up to 54dB noise reduction, our thermally broken systems cut heat loss by up to 65%, and we work directly with borough conservation officers to guarantee compliance. Call 020 7060 1572 for a free London heritage window survey.