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.
A complete service
from design to installation.
We purchased a combination of Alu-Clad windows, Lift & Slide doors and entrance glazing from Zyle Fenster for our family home.
Every member of the team was knowledgeable, approachable and highly professional. Manufacturing quality is outstanding and the installation was carried out with real attention to detail. Even after completion, they followed up to ensure everything was perfect.
It’s rare to find a company that delivers exactly what they promise. We would happily recommend Zyle Fenster to anyone building or renovating a home.
Seán & Emma R. – County Meath
Our architect specified Reynaers aluminium systems and recommended Zyle Fenster for the supply and installation.
The large glazing panels have completely changed the feel of the house while maintaining excellent thermal comfort throughout the winter. The installers were meticulous and every junction was finished beautifully.
It’s refreshing to work with a company that genuinely cares about delivering a quality result.
Niamh F. – County Clare
We chose Schüco aluminium windows and doors through Zyle Fenster for our contemporary home.
Everything about the experience was professional. From technical advice through to installation, the team demonstrated real expertise. The slim profiles look fantastic and the quality of the finish is exactly what we hoped for.
A premium product installed by a premium company.
David L. – County Waterford
Our conservation project required slim glazing without compromising performance, and Zyle Fenster recommended their vacuum glazed timber sash windows.
The result is outstanding. The traditional appearance has been preserved while the improvement in warmth and noise reduction is remarkable. You simply wouldn’t know they contain such advanced technology.
Excellent communication, excellent installation and an exceptional product.
Michael & Sarah K. – County Kilkenny
Finding authentic timber sash windows that also met modern energy standards wasn’t easy until we found Zyle Fenster.
The finished windows perfectly suit our Victorian home while dramatically improving comfort. They operate beautifully and the attention to detail is outstanding.
The installation team treated our home with great respect and left everything spotless each evening. We have received countless compliments from neighbours.
Margaret C. – Dublin
We wanted a large glazed feature overlooking the garden while still achieving excellent thermal performance. The timber curtain wall supplied by Zyle Fenster exceeded every expectation.
The craftsmanship is remarkable and the amount of natural light it brings into the house is incredible. Our architect was particularly impressed with the technical knowledge and attention to detail shown throughout the design process.
Professional, reliable and extremely high-quality workmanship.
Patrick D. – County Wicklow
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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