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Quick Product Snapshot
Key Information at a Glance
Opening Style
Casement, tilt-and-turn and other inward opening options depending on system specification
Frame Material
Thermally broken aluminium hidden sash system
Best Suited For
Contemporary homes, premium renovations, large window openings and minimalist designs
Glazing Options
High-performance double or triple glazing, with system-dependent capacities up to around 40mm on COR 70 Hidden Sash
Energy Performance
COR 70 Hidden Sash can achieve Uw values from around 0.84 W/m²K depending on glazing and configuration
Security
PAS 24 approved specification available with security hardware options
Warranty
Manufacturer and installer warranty details depend on the chosen Cortizo system and supply route
Design & Options
Cortizo hidden sash windows are designed for a cleaner aluminium look, where the sash is visually reduced so the glass area feels larger. This makes them a good fit for contemporary homes and premium renovations where a standard opening sash would look too heavy.
✓ Hidden sash styling gives a more minimal external appearance with more emphasis on the glass.
✓ High-performance glazing can be specified for thermal insulation, acoustic comfort and solar control.
✓ Powder-coated aluminium finishes allow the frame colour to suit the elevation.
✓ Concealed and security hardware options are available on suitable configurations.
✓ Opening styles can be selected to suit room use while keeping a consistent modern façade.
Why choose CORTIZO Hidden Sash Windows
Hidden sash windows are all about making the glass feel more dominant and the frame less visible. They are ideal for homeowners who want the strength and performance of aluminium without a bulky window appearance. The result is sharper, cleaner and more architectural than a standard casement window.
Key Features
Minimal visible sash
for a cleaner exterior look
More glass, less frame
for brighter rooms
Strong aluminium profile
for slim, strong frames
PAS 24 options available
for added reassurance
Performance & Comfort
The thermally broken aluminium construction supports strong insulation, acoustic performance and weather resistance. Depending on specification, COR 70 Hidden Sash offers excellent U-values, sound reduction and security testing while maintaining a very minimal appearance.
Energy Efficient
COR 70 Hidden Sash achieves Uw from 0.84 W/m²K.
Enhanced Security
PAS 24 security test approved.
Weather Resistance
Class 4 air permeability and high watertightness ratings.
Acoustic Comfort
Acoustic insulation up to 46 dB Rw.
Are CORTIZO hidden sash windows right for your property?
Hidden sash windows are ideal when the design calls for more glass and less visible frame. They suit contemporary homes, premium renovations and elevations where a standard opening sash would look too heavy. Use them when you want the clean appearance of fixed glazing, but still need opening windows for ventilation in selected rooms.
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