Secondary Glazing Edinburgh

Listed Building Friendly · No External Change · From £395 per window

Secondary glazing is a discreet internal pane fitted inside an existing sash or casement window — no change to the original window, no change to the streetscape, no Listed Building Consent needed in most cases. For Edinburgh listed buildings, conservation-area tenements and road-noise-affected flats, it's often the right answer when full replacement glazing isn't allowed or isn't worth the cost. Heatscape installs from £395 per window in a single visit.

What secondary glazing actually is

Secondary glazing is a slimline aluminium or timber frame, glazed with 4mm or 6.4mm acoustic-laminate glass, fitted inside the existing window reveal. It sits about 75–150mm behind the original sash and seals against the timber liner with a gasket. Most installations are sliding (two horizontal panels that slide past each other), but lift-out and side-hinged options are available for windows that need rapid escape or full opening. The original sash window stays exactly as it is — secondary glazing is additive, never subtractive.

Thermal performance

Secondary glazing in front of an existing single-glazed sash gives a combined U-value of about 2.0 W/m²K — not as good as a full slim-line double-glazed unit (1.2 W/m²K) but a huge improvement on bare single glazing (5.8 W/m²K). The air gap between the original sash and the secondary panel acts as an insulating cavity. The bigger thermal win is the air-tightness: secondary glazing seals air leakage from the original sash almost completely, so the room stops being draughty even before the slim-line glass is upgraded.

Acoustic performance — the road-noise solution

This is where secondary glazing beats every other heritage glazing option. A 6.4mm acoustic-laminate secondary panel fitted 100mm behind an original single-glazed sash gives a noise reduction of 38–42 dB Rw — better than any double-glazed casement window. On main-road Edinburgh tenements (Leith Walk, Lothian Road, London Road, Newington), it's the only intervention that genuinely fixes traffic noise. Clients report being able to sleep with the bedroom window 'open' (the secondary panel slid back) for the first time in years.

Why it's the listed-building answer

On a Cat A or B listed building, the council will refuse most external alterations to original sash windows. Secondary glazing is internal, reversible, and doesn't touch the original sash — so consent is usually granted, and on Cat C listed buildings often not required at all. We complete the Listed Building Consent paperwork where it is needed (typically for Cat A and B) and the application turnaround is usually 6–8 weeks.

Discreet styling and frame options

Secondary glazing has come a long way from the chunky 1980s aluminium boxes. Our standard frame is a 28mm slim aluminium profile in a powder-coated heritage colour (chartwell green, ivory, black or RAL-matched to the sash). For high-end interiors we use a hardwood frame painted to match the room joinery. The glazing bars can be added to match the original sash pattern (6-over-6 Georgian, 2-over-2 Victorian) so the window reads as a single coherent unit from the room.

Price, lead time and warranty

From £395 per window for a 2-panel slider in aluminium with 4mm float glass, £595 per window with 6.4mm acoustic-laminate glass, £895 per window for a hardwood frame with acoustic glass. Lead time 3–5 weeks, install one window per hour. 10-year workmanship guarantee, 5-year sealed-unit warranty.

Frequently asked questions

Does secondary glazing work for noise reduction in Edinburgh flats?
Yes — 38–42 dB Rw noise reduction on a 6.4mm acoustic-laminate panel fitted 100mm behind an original single-glazed sash. It's the most effective heritage acoustic solution and the only one that genuinely fixes main-road traffic noise on tenement flats.
Do I need Listed Building Consent for secondary glazing?
On Cat A or B listed buildings, usually yes — but consent is almost always granted because secondary glazing is internal and reversible. On Cat C listed buildings, often not required. We handle the paperwork.
How does secondary glazing compare to slim-line double glazing?
Slim-line double glazing has better thermal performance (1.2 vs 2.0 U-value). Secondary glazing has dramatically better acoustic performance (38 vs 28 dB). For listed buildings or noise problems, secondary glazing wins. For thermal-only upgrade on a non-listed property, slim-line wins.
Will secondary glazing make my windows look ugly from inside?
Modern 28mm aluminium frames in heritage colours are very discreet — most visitors don't notice them. Hardwood frames painted to match the room joinery are essentially invisible.
Can I still open my original sash windows with secondary glazing fitted?
Yes — the secondary panel slides or lifts out, then the original sash opens as normal behind it. The secondary glazing is additive, never subtractive.
How long does secondary glazing take to install?
About one hour per window. A typical seven-sash tenement flat is installed in a single day with no mess, no scaffold and no carpet lift.

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