APA 70 Hidden Sash Window System
Overview
The APA 70 Hidden Sash Window offers a clean, modern look with excellent performance for contemporary homes. The system hides the sash fully behind the outer frame, creating a slim, minimalist appearance. Because of this, it suits homes that want more natural light and a refined, uninterrupted exterior design.
Modern Architectural Design
This concealed sash system creates a seamless finish when viewed from outside the building. The slim profile enhances the glazed area, helping rooms feel brighter and more open. Inside the home, the flush, simple lines complement a wide range of interior styles, from modern extensions to high-end refurbishments.
The design is ideal for projects aiming to maximise natural daylight while maintaining a high-quality architectural aesthetic.
Thermal & Acoustic Performance
The APA 70 Hidden Sash Window uses thermally broken aluminium profiles and advanced insulation materials. These features reduce heat loss and help improve the building’s overall energy efficiency. Depending on the glazing choice, the system supports both double and triple glazing.
This flexibility allows homeowners to tailor the window’s performance to their needs—whether the focus is stronger insulation, enhanced noise reduction or a balance of both.
Durability & Low Maintenance
The system is built for long-term performance. The aluminium construction ensures strong resistance to weather and wear, while the hidden sash design requires little maintenance. Because of this, the APA 70 Hidden Sash Window remains reliable and easy to operate throughout its service life.
The system blends a modern architectural look with practical performance, making it suitable for a wide range of residential design styles.
Ideal Applications
This window works well in:
- Modern private homes
- Residential extensions
- High-end refurbishments
- Multi-unit developments
- Contemporary apartment designs
Its combination of elegant design and robust performance makes it a strong choice for many residential environments.
For more information regarding our APA 70 Hidden Sash Window System range, get in touch with us here.
- Frame depth: 70 mm thermally broken aluminium system
- Hidden sash design – sash completely concealed behind the outer frame for minimal sightlines
- Visible section: 66 mm (frame + sash combination)
- Thermal insulation: Polyamide thermal break system with high-density insulation rods
- Finishes: Single or dual-colour powder coating with over 200 RAL colours available in single or dual finish
- Glazing options: Double or triple glazing up to 40 mm thickness
- Air permeability: Class 4 (EN 12207) Water tightness: Class E1200 (EN 12208) Wind resistance: Class C5 (EN 12210)
- Acoustic performance: Up to 46 dB (depending on glass type)
- Opening possibilities: Side hung, top hung, tilt & turn, fixed light, or combination units
- Hardware: Multi-point locking system for enhanced security
- Can be pre-assembled in-house saving installation time/cost
- Matching rebate doors available
- Identical sight lines throughout
- Includes multi-point locking for added security
| Thermal transmittance | Uw ≥ 0,84 (W/m²K) | |
| Acoustic insulation | Rw up to 46 dB | |
| Air permeability | Class 4 | |
| Water tightness | Class 1800 | |
| Wind resistance | Class C5 | |
| PAS24 security test | Approved | |
| Sections | Frame 70 mm, Sash 70 mm | |
| Polyamide bar length | 35 mm | |
| Profile thickness | Window 1.9 mm | |
| Glazing | Max. 40 mm, Min. 26 mm | |
| Maximum sash weight | 160 kg |
*Whole window U values are a combination of the frame and glazing thermal performance and as such will vary with the specification of glass utilised. Please consult with the APA technical team for more specific performance information.
