A timber frame and 71 mm-deep sashes accommodate a 40–48 mm triple-glazed unit with two Low-E coatings and argon-filled cavities. The result is a whole window U-value of 1.1 W/m²K, with the cord, weight and pulley operation of a traditional sash.
Full frame, glazing and tested weather-tightness data for your architect, energy consultant or builder.
| Product guidance – as standard | |
| Frame | 100 x 192 mm (lining width x frame depth). Mortise and tenon joints, glued and mechanically fixed |
| Sash | 39 x 71 mm top rail and stiles, 90 x 71 mm bottom rail, 45 x 71 mm meeting rail |
| Mullion / transom | 39 x 71 mm top rail and stiles, 90 x 71 mm bottom rail, 45 x 71 mm meeting rail |
| Sill projection | 35 mm, 50 mm, 60 mm, 70 mm |
| Staff / parting beads | Timber |
| Wood moisture content | 12–19% |
| Glazing beads | Internally beaded with external rebate up-stand giving the appearance of putty glazing |
| Air permeability | 600 Pa (Class 3) – EN 1026 / EN 12207 |
| Water tightness | 200 Pa (Class 5A) – EN 1027 / EN 12208 |
| Wind resistance | 1600 Pa (Class 4) – EN 12210 |
| Whole window U-value | 1.1 W/m²K to EN ISO 10077-1 |
| Whole window acoustic rating | 29 dB (-2;-4) with 4/16/4/16/4; 30 dB (-1;-2) with 6/14/4/14/8.8 (44.2 laminated acoustic) – BS EN ISO 10140-2:2021 |
| Anticipated life expectancy | 60 years with regular maintenance |
| Product Specification | |
| Material | Frame and sash in engineered redwood, bottom cill in solid hardwood (standard). Engineered hardwood, Accoya or European oak optional |
| Finish | Three-coat spray-applied factory finish using water-based microporous paint/stain (Teknos Aqua prime 1410, Aqua mid 2901, Aqua top 2600) |
| Colour | White – RAL 9016 (standard). Any RAL from RAL Classic range. Stain from Zyle Fenster stain range |
| Glazing | Triple glazed, 4/14/4/14/4 Low-E top sash – 4 tgh/14/4/14/4 tgh bottom sash (standard). Ug-value 0.6 W/m²K; g-value 0.52–0.55 |
| Glass standard | Factory-fitted 40–46 mm sealed triple-glazing unit tested to BS EN 1279. Composition (from outside): 4 mm float Low-E – 16 mm argon – 4 mm float – 16 mm argon – 4 mm float Low-E |
| Perimeter spacer bars | White warm edge perimeter spacer with white warm edge integral spacers (standard). Silver and black optional |
| Glazing bars | Applied bars to both faces of sealed unit, fixed with double-sided glazing tape and capped with clear silicone |
| Trickle ventilation | Concealed through frame head trickle ventilator. EA 1700, 4400, 5000 mm² |
| Child restrictor | Angel lock (standard). Traditional Sash Stop optional. Optional 100 mm opening restrictor |
| Operation | Cord, weight and pulley system concealed within the frame |
| 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 colour and finish |
| Cill | Hardwood. Projections 35–110 mm |
| Horns | Solid feature horns to top sashes included as standard |
| 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 Triple Glazed Sash brochure, datasheets and CAD details for your project.
The Triple Glazed Sash keeps the cord, weight and pulley operation of a heritage window while accommodating a glazing unit deep enough to deliver Passivhaus-aligned thermal performance.
It is the right answer where the look of the home calls for a sash, but the way you want to live in it calls for modern fabric performance.
Frames and sashes are made in engineered redwood, hardwood, Accoya or European oak, with a solid hardwood cill as standard.
A factory-applied Teknos three-coat finish is available in any RAL or wood stain, with concealed trickle ventilation, child restrictors and a full ironmongery range to complete the window.
Honest answers to the questions self-builders and homeowners ask when specifying triple glazed timber sash windows for a new or upgraded home.
Contact UsFor new builds and well-insulated homes, yes. Triple glazing reduces heat loss, removes cold spots near the window and lowers heating bills throughout the year.
A whole window U-value of 1.1 W/m²K is typical, with a centre-pane Ug of 0.6 W/m²K. In practice, this means warmer rooms, no condensation and far less perceived draught near the glass.
Yes. The Triple Glazed Sash is suitable for Passivhaus and low-energy homes. We will review your project targets and confirm the right glazing make-up to support certification.
Yes. Sashes are slightly deeper to accommodate the triple-glazed unit, but front-face profiles, sash horns and applied glazing bars maintain the traditional appearance on the elevation.
Yes. Laminated acoustic panes can be specified within the triple-glazed unit, achieving 30 dB or higher, particularly useful for homes on busy roads or in urban locations.
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.
Please complete the form below to access this download.
