Secondary Glazing
Listed Buildings & Conservation Areas
Conservation-friendly secondary glazing that preserves historic windows while delivering modern comfort. Recommended by Historic England and usually requiring no listed building consent — the sympathetic upgrade for protected homes across London and Hertfordshire.
- FENSA
- Which?
- CERTASS
- TrustMark
Heritage-friendly
Modern comfort that respects your home's heritage
Listed buildings and homes in conservation areas are protected for good reason, but that protection often makes upgrading draughty single-glazed windows difficult. Replacing original windows is frequently refused, leaving owners with cold, noisy rooms and rising energy bills.
Secondary glazing is the answer. Recognised by Historic England as the preferred method for improving historic windows, it sits internally, is fully reversible, and leaves the protected fabric untouched. That means you can dramatically improve warmth and quiet — usually without the need for listed building consent.
Why choose it
The conservation-friendly choice
Historic England recommended
Secondary glazing is the conservation sector's preferred way to upgrade historic windows.
Usually no listed consent
As a reversible internal system it rarely requires listed building consent — we advise on each case.
Preserves original fabric
Your historic windows, glass and joinery remain completely untouched and fully reversible.
Sympathetic sightlines
Slimline frames and discreet finishes respect the character of period and protected homes.
Conservation-area friendly
Ideal across London's conservation areas where external alterations are tightly controlled.
Thermal & acoustic gains
Genuine warmth and quiet without compromising heritage value or appearance.
Local coverage
London conservation areas we serve
Greater London has over 1,000 conservation areas across its 32 boroughs. Each has its own design guidance — but the principle is the same: alterations must preserve the historic character of the streetscape. Secondary glazing is widely accepted because it's invisible from the street and fully reversible. We work with conservation officers across all London boroughs, including these well-known conservation areas:
Camden & North London
- Hampstead Conservation Area
- Highgate Village Conservation Area
- Primrose Hill Conservation Area
- Belsize Conservation Area
- Fitzjohns & Netherhall Conservation Area
- Camden Town Conservation Area
- Kentish Town Conservation Area
Kensington, Chelsea & West London
- Notting Hill Conservation Area
- Holland Park Conservation Area
- Kensington Conservation Area
- Chelsea Conservation Area
- Brompton Conservation Area
- Earl's Court Square Conservation Area
- Norland Conservation Area
Westminster & Central London
- Belgravia Conservation Area
- Mayfair Conservation Area
- Marylebone Conservation Area
- Bloomsbury Conservation Area
- Soho Conservation Area
- Covent Garden Conservation Area
- Pimlico Conservation Area
- St James's Conservation Area
Islington & East London
- Canonbury Conservation Area
- Barnsbury Conservation Area
- Highbury New Park Conservation Area
- Clerkenwell Conservation Area
- Spitalfields Conservation Area
- Wapping Conservation Area
- Bethnal Green Conservation Area
South & South-East London
- Greenwich Park Conservation Area
- Blackheath Conservation Area
- Dulwich Village Conservation Area
- Clapham Common Conservation Area
- Brixton Conservation Area
- Bermondsey Conservation Area
Outer London & Hertfordshire
- Richmond Hill Conservation Area
- Kew Green Conservation Area
- Twickenham Riverside Conservation Area
- Cheshunt Conservation Area
- Hertford Conservation Area
- Bishop's Stortford Conservation Area
Property in a conservation area not listed here? We work across all 32 London boroughs and every Hertfordshire district. The principles of secondary glazing apply to every conservation area — bespoke survey, sympathetic frame design, no permanent alteration. Call 01992 636400 or request a free survey.
Transparent pricing
What does secondary glazing cost?
Secondary glazing is priced per window, and the final cost depends on size, system type, glass specification and frame finish. The figures below are typical retail ranges for installed secondary glazing units in London and Hertfordshire — every survey we provide is fixed, written and free of obligation.
| System type | Typical size | Standard 4mm glass | Acoustic / thermal glass |
|---|---|---|---|
| Lift-out / fixed panel | Small (up to 0.8m²) | £350–£550 | £450–£700 |
| Horizontal sliding | Medium (0.8–1.5m²) | £450–£750 | £600–£950 |
| Vertical sliding sash | Medium (0.8–1.5m²) | £550–£900 | £700–£1,200 |
| Side-hung casement | Medium (0.8–1.5m²) | £500–£850 | £650–£1,100 |
| Bespoke bay / angled | Per bay (3–5 panels) | £1,400–£2,800 | £1,900–£3,800 |
Prices include survey, manufacture and installation. Frame colours, hardware finish and glass specification are all included in your fixed written quote — no hidden extras.
Volume discounts available for whole-house installations (5+ windows). Many of our customers spread payments across a 2–3 month installation programme — ask us about phased works during your survey.
How it works
From first call to aftercare
- 01
Heritage survey
We assess your windows and any planning or listed-building considerations.
- 02
Design
We specify discreet, sympathetic units matched to your home's character.
- 03
Manufacture
Each unit is made to measure to preserve original sightlines.
- 04
Installation
Careful, reversible installation that protects historic fabric.
- 05
Aftercare
Fully guaranteed, with friendly aftercare whenever you need it.
FAQs
Listed building secondary glazing FAQs
Explore
More secondary glazing services
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