Research Book
Climate Emergency Heritage Sash Window
Best Practice - Vacuum Glazing
Christopher Procter surveys and analyses current UK Vacuum Glazing technology in regard to heritage sash for refurbishment or replacement with thermal and carbon benefits described. This guide expands on detailed research from the 2023 CA Toolkit, including new companies and products. It compiles information and methods that are not otherwise available for this rapidly evolving technology.
Publisher: Spatial Interference Ltd
Publication Date: 2 October 2025
Binding: Booklet
Pages: 56 pages
Paper weight: 100gsm
Cover weight: 250sqm
Colour: Full Colour / matt
Size: A4 297mm(h) x 210mm(w).
Format: PDF & Paperback Print
The report concludes that;
Slimline double-glazing should no longer be the preferred choice for heritage.
Vacuum glazing is now a developed product and can now be the best option for heritage. This technology provides an opportunity for window glazing improvements to both meet Building Regulations and improve heritage.
Plant-on bars on vacuum glazing should be used for replacement windows.
Integral through glazing bars should be used only where original sash must be retained in listed buildings.
Double-glazed, triple-glazed and hybrid vacuum are appropriate in some cases.
Frame innovations such as mock sash or fixed top sash can extend glazing UValue gains as total window UValues are based on glazing, frame, and seals.
Clear and consistent glazing policies will produce better climate mitigation and make planning more efficient, saving councils and householders costs and time.
