Two tempered glass panes sealed under vacuum produce a glazing unit just 8.3mm thick, the same visible thickness as the original Georgian or Victorian glass. Combined with slim sashes and putty-glazed external detail, it is the right answer where conventional double glazing would be refused.
Tested air, water and wind performance with whole-window thermal data for your architect or planning consultant.
| Product guidance – as standard | |
| Sill projection | Hardwood. Projections 35 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm |
| Wood moisture content | 12% +/- 2% on delivery |
| Glazing beads | Internally beaded with external rebate up-stand giving the appearance of putty glazing |
| Air permeability | 600 Pa (Class 3) – EN 12207:2017 |
| Water tightness | 200 Pa (Class 5A) – EN 12208:2002 |
| Wind resistance | 1600 Pa (Class 4C) – EN 12210:2016 |
| Whole window U-value | 1.2–1.1 W/m²K to EN ISO 10077-1:2006 |
| Whole window acoustic rating | Rw 29–34 dB tested to BS EN ISO 10140-2:2010 |
| Anticipated life expectancy | 60 years with regular maintenance |
| Product Specification | |
| Material | Engineered laminated pine, hardwood or Accoya. FSC or PEFC certified |
| Finish | Factory finished externally and internally with Teknos water-based microporous opaque to specified RAL or stain (Aqua prime 1410, Aqua mid 2901, Aqua top 2600) |
| Glazing | 8.3–12.3 mm sealed vacuum-glazing unit. Two flat tempered glass panes separated by micro support pillars and sealed with a vacuum chamber |
| Glazing bars | Applied bars to both faces of sealed unit, fixed with double-sided glazing tape and capped with clear silicone |
| Trickle ventilation | Controllable trickle ventilator dependent on frame width. EA 2000, 4400 mm² |
| Child restrictor | Optional 100 mm opening restrictor |
| Operation | Cord, weight and pulley system concealed within the frame. Spring balance option available |
| Timber species | Engineered laminated pine, hardwood or Accoya. FSC or PEFC certified |
| Moisture content | 12% +/- 2% on delivery |
| Ironmongery | Lockable Fitch fastener and two finger pulls to bottom sash. Options in antique brass, polished chrome, satin nickel, polished brass, matt bronze, polished nickel |
| Cill | Hardwood. Projections 35–110 mm |
| Horns | Solid feature horns to top sashes included as standard |
| Sustainability | Fully recyclable glazing units with no noble gases |
| Fixing | Installation per Zyle Fenster recommendations and best building practice |
| Warranty | 10-year manufacturing and material defects; 10-year opaque finishes; 6-year stain finishes; 10-year sealed unit seals; 2-year ironmongery |
Download the Vacuum Glazed Sash brochure, datasheets and CAD details for listed and conservation submissions.
Vacuum glazing brings modern insulation behind a sightline that satisfies the strictest conservation officer. The 8.3mm unit reads as single glazing on the elevation while performing closer to a triple-glazed window.
It is the right specification when planning consent rules out standard double glazing, but you still want a warm, quiet home.
Operated on traditional cords, weights and pulleys, the window is built to last in engineered redwood, hardwood or Accoya, with a solid hardwood cill as standard.
A factory-applied three-coat Teknos finish is hand-applied in any RAL or wood stain, so the window arrives ready to be installed.
Honest answers to the questions period homeowners ask about vacuum glazing, listed building consent and warmth.
Two thin tempered glass panes are separated by tiny support pillars with a vacuum drawn from the cavity. The vacuum dramatically reduces heat loss while keeping the unit visibly slim.
In most cases, yes. The 8.3mm thickness and single-pane appearance mean vacuum glazing is frequently accepted by conservation officers where standard double glazing would be refused.
Whole window U-values of 1.2 to 1.1 W/m²K are typical, a significant improvement on original single-glazed sashes and comparable to a modern double-glazed window.
Vacuum glazing seals are guaranteed for 10 years from delivery. The units contain no noble gases and are fully recyclable at the end of their life.
Yes. Different glass make-ups, including laminated acoustic panes, are available to reach 34 dB or higher, helpful in town and city locations or near busy roads.
Whether incorporated into a modern contemporary new build or unlocking a period property, our curtain wall can reinvigorate a property by letting the natural daylight come flooding in.
Find out more about Dollar, ScotlandA complete service
from design to installation.
Zyle supplied Passive House windows for our new build, and the system met all project expectations. Airtightness and overall performance were delivered as specified, and their technical coordination on site was reliable and detail focused.
Private Owner
Mark Reynolds, Bristol
Our vacuum glazed sash windows provide an excellent balance between heritage sensitivity and modern performance. The slim glazing preserves the character of the property while significantly improving overall comfort. Installation was precise and professionally managed.
Private owner
Laura Mitchell, Southampton
The Passive House windows performed exactly as required within our project specification. Installation detailing, sealing, and overall execution were handled correctly, ensuring a high standard of delivery. A technically competent and reliable supplier.
Private Owner
Andrew Collins, Cambridge
We selected aluminum windows for their contemporary aesthetic and low maintenance. The proportions are well considered, and the finish quality is consistent throughout. Installation was efficient and carried out with strong attention to detail.
Private Owner
Rachel Adams, Reading
The triple glazed sash windows integrate seamlessly into the existing façade while offering a clear upgrade in comfort. Craftsmanship is evident in both joinery and installation, and the improvement in acoustic insulation is immediately noticeable.
Private Owner
Thomas Green, Nottingham
The Alu-Clad windows and doors introduced a strong architectural presence while maintaining a refined internal finish. Detailing, material quality, and consistency across the project are of a high standard. The process was structured and dependable from start to finish.
Private Owner
Olivia Bennett, Oxford
Whether you are an architect specifying for a new project, a self-builder planning your custom home, or a developer working to a programme, our team is here to help. Get in touch for technical advice, product information, or to request a quote.
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