Secondary glazing in London
From £350
| Service | Typical price in London |
|---|---|
| UPVC double glazed windows | £563 - £1,125 |
| Sash windows (UPVC & timber) | £1,125 - £3,000 |
| French & patio doors | £1,625 - £4,000 |
| Bay & bow windows | £2,000 - £4,750 |
| Secondary glazing | £438 - £1,188 |
Secondary glazing quotes for listed and conservation London properties
Secondary glazing is the workhorse solution for London’s listed and conservation-area stock: Georgian squares in Kensington and Camden, Victorian mansion blocks in WC1 and NW1, and any street inside an Article 4 Direction where the primary sash cannot be altered at the front. Legacy Windows is a quote comparison service that shortlists installers specialising in reversible internal units, not casement replacement.
Why locals in London choose Legacy Windows
- Realistic London pricing on internal secondary units is £438 to £1,188 per opening in 2026, depending on frame material and glass spec
- Firms we match you with fit horizontal sliders, vertical sliders and lift-out panels sized to the original sash reveal
- Acoustic laminate glass is quoted separately for streets on TfL red routes, near stations, or under Heathrow flight paths in Hounslow and Richmond
- Listed Building Consent applications are handled where the primary window is Grade I or II listed
- Every quote separates frame, glass, brushes and installation, so a like-for-like comparison across three installers is straightforward
Areas we cover around London
Demand is heaviest in WC1 Bloomsbury, W1 Marylebone, SW1 Belgravia and Pimlico, SW3 Chelsea, W8 Kensington, W11 Notting Hill and NW1 Camden, plus period conversions across N1 Islington, SE1 Bermondsey and E1 Whitechapel. Mansion blocks in W2 Bayswater and SW5 Earl’s Court are a recurring category, where thick brickwork reveals allow a deep secondary unit that halves traffic noise.
Frequently asked questions
Does secondary glazing need Listed Building Consent in London? Usually yes for a Grade I or II listed property, though most local authorities recognise it as reversible and low-impact. The application is far simpler than replacing the primary sash. Installers in our network prepare the drawings as part of the quote.
Will secondary glazing meet Part L on a listed London flat? Listed buildings are largely exempt from Part L when full compliance would harm the historic fabric. Secondary glazing typically gets the combined unit down to around Uw 1.7 W/m²K, which is the accepted heritage benchmark.
How much noise reduction can I expect on a busy Camden street? A 100mm cavity between the primary sash and a 6.4mm acoustic laminate secondary pane delivers around 45dB reduction, enough to make Camden Road or Euston Road audible only as a distant hum.
Windows and doors in London - local context
Victorian and Edwardian terraces dominate inner boroughs, alongside interwar semis in outer London, 1960s-70s tower blocks, and modern glass-fronted apartments in redevelopment zones like Nine Elms and King's Cross.
Dominant era of housing stock: Victorian to Edwardian across inner London, interwar in outer boroughs.
Heritage note: London has over 1,000 conservation areas across 33 boroughs - always check with the local council planning portal before ordering.
- Islington
- Hackney
- Camden
- Wandsworth
- Greenwich
- Ealing
- Croydon
Postcodes we cover in London
- E1
- EC1
- N1
- NW1
- SE1
- SW1
- W1
- WC1
- W2
- N7
- SE15
- SW9
- E14
- E17
Not seeing your postcode? Request a quote anyway - we likely still cover it.