Why install secondary glazing behind sash windows?
Original sash and case windows are a defining feature of many Scottish homes. Their fine glazing bars, timber frames and proportions can be difficult to reproduce with modern replacements. Yet single glazing and ageing seals may leave rooms feeling cold or exposed to street noise.
Secondary glazing introduces an additional glazed unit on the room side of the existing window. The air space between the two windows can improve thermal and acoustic performance. The actual improvement depends on glass specification, installation quality, existing window condition and the distance between the panes.
Key advantages include retaining original windows, discreet internal installation, improved comfort and the option to open the secondary unit for ventilation and access. Where timber sashes are in poor condition, repairs and draught-proofing may also be appropriate before installation.
Granada vertical sliding secondary glazing
For traditional vertically opening sash and case windows, Granada’s balanced vertical sliding system is a particularly suitable option. Its two sliding glazed panels are designed to complement the operation and proportions of the original window. Spring balances support the panels so they can remain at selected positions. Depending on specification and survey findings, tilt-in configurations may also be available to assist access for cleaning.
The system uses slim aluminium profiles and is made to measure. We will discuss glazing, frame finish, reveal depth, opening access and any practical limitations during the quotation process.
Warmer rooms without replacing original windows
A carefully specified secondary glazing system can reduce heat loss through the window assembly and help make rooms feel less draughty. Low-emissivity glass may be considered where thermal performance is a priority. We do not promise a fixed percentage saving on heating bills: results vary with the building, existing glazing, ventilation and use.
Reduce traffic and street noise
If your home faces a busy road, railway or lively street, acoustic secondary glazing may make a noticeable difference. A suitable air gap, well-sealed frames and acoustic laminated glass can all contribute. The right specification depends on the noise source and the existing window. We can discuss acoustic options when preparing your quotation.
Secondary glazing for listed buildings and conservation areas
Retaining original sash windows is often especially important in listed buildings and conservation areas. Internal secondary glazing can be a less visually intrusive alternative to replacement windows. However, listed building consent or other permissions may still be required, depending on the property and the work proposed. We recommend confirming requirements with the relevant planning authority before installation.
Learn about secondary glazing for listed buildings (check and replace with the live page URL)
What happens when you request a quotation?
- Tell us your location, approximate number of windows and main concerns, such as heat loss or noise.
- Share photographs of the windows and surrounding reveals where possible.
- We review the opening style and discuss an appropriate Granada system.
- We confirm survey arrangements, specifications and a tailored quotation.
- Once agreed, the made-to-measure units are supplied and professionally installed.
How much does sash window secondary glazing cost?
Every installation is different. Price depends on window dimensions, number of units, glazing specification, opening mechanism, frame finish and installation access. Vertical sliding systems can cost more than simpler fixed panels, but are often the most practical choice for working sash windows.
Read our secondary glazing cost guide or request a tailored quotation.
Areas we serve
EcoShield focuses on professionally installed secondary glazing in Central Scotland, including Stirling and surrounding communities. Contact us about projects elsewhere in Scotland so we can confirm survey and installation availability before making arrangements.
Frequently asked questions
Can I keep my existing timber sash windows?
Yes. Secondary glazing is fitted internally, so the original sash windows can usually be retained, subject to their condition and the installation details.
Will the secondary glazing open?
Yes, Granada’s balanced vertical sliding units have sliding panels designed for access and ventilation. The most suitable configuration depends on the window.
Is secondary glazing suitable for a listed building?
It can be, but the need for consent must be checked for the specific building and proposed installation.
Will it stop condensation?
It may improve interior surface temperatures, but condensation is influenced by ventilation, humidity, sealing and the condition of the original window. No system can guarantee that condensation will disappear.
Can it help with road noise?
Yes, appropriately specified secondary glazing can reduce sound transmission. The result depends on the existing window, acoustic glass, air gap and installation details.
Request a quotation
Preserve your original sash windows while improving everyday comfort. Tell EcoShield about your property and we will discuss the right professionally installed Granada secondary glazing solution.