Published by InGlaze | Aberdeen, Scotland
If you live in a listed building or a conservation area in Scotland, you’ll know the frustration. Your home is beautiful — full of character, original features, and history. But it’s also cold, draughty, and expensive to heat. And when you ask about double glazing, the answer is almost always the same: you can’t.
So what are your options? The good news is that secondary glazing is not only permitted in most listed buildings — it’s specifically recommended by Historic Environment Scotland as the preferred solution. Here’s everything you need to know.
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Why Listed Buildings Can’t Usually Have Double Glazing
In Scotland, listed buildings are protected under the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997. Properties are listed as Category A, B, or C depending on their architectural or historic significance, and any alterations — including changes to windows — require Listed Building Consent from your local planning authority.
Standard double glazing is almost always refused in listed buildings because replacing original windows changes the character of the building in ways that planning authorities won’t accept. uPVC frames are a non-starter. Even where slim-profile double glazing might be considered, it is assessed case by case and frequently rejected — particularly in Category A and B listed properties.
If you live in a conservation area (but your property isn’t individually listed), the rules are slightly different but still restrictive. Any changes that affect the appearance or character of the area require approval, and window replacements are tightly controlled.
The result is that thousands of Scottish homeowners — particularly in cities like Aberdeen, Edinburgh, Glasgow and their surrounding areas — are left living in cold, draughty homes with no obvious route to better insulation.
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Why Secondary Glazing Is the Approved Solution
Secondary glazing involves fitting a second panel on the inside of your existing window, creating an insulating air gap — without touching, altering, or replacing the original window at all.
Because it is:
– Fitted internally— invisible from the outside;
– Completely reversible — removed without any damage to the original window or frame;
– Non-invasive — does not alter the historic fabric of the building;
secondary glazing is generally accepted by Scottish planning authorities without requiring Listed Building Consent in most cases. Historic Environment Scotland’s own guidance supports secondary glazing as a sympathetic solution for improving thermal performance in historic buildings.
That said, we always recommend checking with your local planning authority or conservation officer before proceeding — requirements can vary by council and by the specific listing of your property.
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Not All Secondary Glazing Is Equal — What to Look For
Here’s something that isn’t often talked about: secondary glazing only works well in listed buildings if the system can cope with imperfect, irregular, or aged window frames. And that’s where many systems fall short.
Traditional stone and granite buildings — common throughout Aberdeen and the North East of Scotland — often have window frames that have shifted, warped, or settled over decades or centuries. A secondary glazing system that relies on a rigid seal will leave gaps, let in draughts, and fail to deliver the thermal performance you’re paying for.
When choosing secondary glazing for a listed building, look for:
1. An adaptive seal
The seal that connects the secondary glazing panel to your window frame needs to accommodate uneven surfaces. Without this, the system simply won’t be airtight.
2. Independent performance testing
Anyone can claim their product reduces heat loss. Ask to see independent, third-party test results from a recognised facility.
3. Full reversibility
The system must be completely removable without any damage to the original window, frame, or surrounding structure. This is both a planning requirement and a practical necessity.
4. Custom manufacture
Listed buildings rarely have standard window sizes. Your secondary glazing should be precision-made for each individual window — not cut from a standard sheet.
5. Clarity
The panel itself should be crystal clear so as not to affect light levels or the appearance of your windows from inside the property.
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How InGlaze Is Designed Specifically for Scotland’s Listed Buildings
InGlaze was founded in Aberdeen by Luci and Campbell, who identified a genuine gap in the market: thousands of Scottish homes in listed buildings and traditional granite properties with no affordable, approved route to better insulation. We built InGlaze to fill that gap.
Here’s what makes InGlaze different:
Patent-pending adaptive seal
Our unique flexible seal is specifically designed to accommodate uneven, aged, and irregular window frames — the kind found throughout Aberdeen’s traditional granite terraces and Scotland’s historic housing stock. It creates a genuinely airtight fit even where other systems can’t.
Independently proven performance
InGlaze secondary glazing was tested at the **University of Salford Energy House Labs** — the UK’s leading facility for real-world building performance research. The results were independently verified:
– 50% reduction in heat loss when fitted as a whole-window solution
– 41% reduction in heat loss when fitted to individual sashes while maintaining window operation
We don’t ask you to take our word for it. The full report is available to read on our website.
Precision manufacture in Aberdeen
Every InGlaze panel is custom-cut at our Aberdeen factory using CNC laser processing and precision measuring equipment. We can accommodate all window shapes and sizes — including arched windows, stained glass, and the wide range of non-standard window sizes found in Scottish heritage properties.
Crystal-clear 3mm acrylic
Our panels are made from high-quality crystal-clear acrylic, meaning they are barely visible once fitted and do not affect the light or appearance of your windows.
Fully reversible
InGlaze attaches to the window frame using our adaptive seal — no drilling, no permanent fixings, no damage. It can be fully removed at any time, leaving the original window completely untouched.
Scottish EDGE Award Winners
InGlaze was recognised as the North East Regional winner of the first Scottish EDGE Regional Edge Award and a winner in the national Scottish EDGE Round 25 Award — one of Scotland’s most competitive business innovation awards.
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What About Aberdeen’s Granite Homes?
Aberdeen is home to thousands of traditional granite properties — many of which sit within conservation areas or are individually listed. These homes are notoriously difficult to insulate: the thick stone walls hold the cold, the original sash windows are single-glazed, and double glazing is almost never an option.
InGlaze was designed with exactly these properties in mind. Our adaptive seal works particularly well on the aged timber frames common in Aberdeen’s traditional housing stock, and our Aberdeen factory means we understand the local building stock better than any supplier based elsewhere in Scotland.
Whether you’re in the West End, Ferryhill, Rosemount, or anywhere across Aberdeenshire — we can come to you, measure your windows, and provide a free no-obligation quote.
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The Bottom Line
If you live in a listed building or conservation area in Scotland and you’re struggling with cold rooms, draughty windows, high heating bills, or condensation — secondary glazing is almost certainly your best option. It’s approved, effective, reversible, and significantly more affordable than any alternative.
But the quality of the system matters enormously, particularly in older properties with irregular frames. Make sure whatever system you choose has been independently tested, is precision-made for your windows, and uses a seal that can genuinely cope with imperfect frames.
If you’d like to find out whether InGlaze is right for your property, we’d love to hear from you.
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Get a Free Quote
Contact us for a free, no-obligation quote. We serve Aberdeen, Aberdeenshire, and properties across Scotland and the UK.
– Call: 03030 033 244
– Email: contact@inglaze.uk
– Or use our contact form at inglaze.uk/contact-us
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InGlaze is an Aberdeen-based manufacturer of secondary glazing, independently tested by the University of Salford and winner of Regional EDGE (North East) 2025 and the Scottish EDGE Round 25 Award.