Cortizo Casement Windows

Slim Aluminium Windows, Supplied & Fitted Across London

Looking for windows that let in more light, keep in more heat, and stay looking sharp for decades? Cortizo Casement Windows do exactly that. Slim frames. Big glass. Serious performance. At 4 Moon Windows, we supply and install aluminium casement windows across Croydon, Thornton Heath, and Greater London. Every window is made to measure, fitted by our own team, and backed by proper aftercare — not a call centre. Cortizo is one of Europe's largest aluminium systems manufacturers, and its casement range was designed specifically for the UK market. That means outward-opening windows, British weather testing, and PAS 24 security certification as standard options — not afterthoughts.

WHAT MAKES CORTIZO DIFFERENT?

What Makes Cortizo Aluminium Casement Windows Different?

70mm Frames with a Deep Thermal Break

Plenty of companies sell aluminium windows. Not all aluminium is equal. Cortizo Casement Windows use a 70mm frame with a deep 32mm polyamide thermal break. In plain English, that's an insulating barrier inside the frame that stops heat escaping through the metal. It's one of the deepest thermal breaks in its class.

More Glass, More Daylight

The result? U-values from just 1.0 W/m²K — and as low as 0.9 W/m²K with triple glazing. That's the kind of performance that cuts heating bills and keeps your home comfortable through a damp London winter. You also get a much better glass-to-frame ratio than uPVC or timber. Slimmer sightlines mean more glass, more daylight, and rooms that simply feel bigger.

Standard or Flush Casement — Your Choice

Cortizo offers two looks, and we fit both: Standard casement: The sash sits slightly proud of the frame. Clean, contemporary, and a great fit for modern homes and extensions. Flush casement: The sash sits perfectly level with the frame for a smooth, seamless face. If you're searching for aluminium flush casement windows in Croydon, this is the style turning heads on period properties and new builds alike. Both versions open outward — side-hung or top-hung — and both can be combined with fixed panes, bays, and shaped frames for a fully bespoke design.

WHY CHOOSE ALUMINIUM?

Why Homeowners Across the UK Are Switching to Aluminium

If you’re weighing up aluminium casement windows in the UK against uPVC or timber, here’s the honest picture.

Aluminium lasts longer. A well-made aluminium frame will comfortably outlive uPVC, which can discolour and warp over time. Aluminium doesn’t rot like timber, either. Expect 40+ years of service with almost no upkeep.

Perfect for Replacements, Extensions & New Builds

Cortizo Casement Windows are designed to suit a wide range of properties, from traditional homes to contemporary developments.

Home Replacements

Designed as a direct replacement for tired timber and uPVC frames, they can modernize older properties without major structural changes. Slim profiles also bring more natural light while maintaining the character of the original home.

New Builds & Modern Homes

Cortizo systems complement contemporary architecture, particularly floor-to-ceiling glazing and minimalist designs.Their versatile configurations give architects and homeowners greater freedom when creating modern spaces.

Extensions & Loft Conversions

The clean aluminium design works beautifully in kitchen extensions, loft conversions, and open-plan living spaces. Large glazing areas help create brighter interiors and seamless connections between indoor and outdoor spaces.

Commercial Properties

The same high-performance system is suitable for offices, shops, apartments, and other commercial developments. Durable aluminum construction combines a professional appearance with reliable long-term performance.

Slimmer Frames. Warmer Rooms. Lower Bills.

READY TO TRANSFORM YOUR HOME WITH CORTIZO?

Get your free, no-obligation quote today. Call us, WhatsApp us, or book a quick chat online — and see why homeowners across Croydon and London trust 4 Moon Windows for premium aluminium casement windows.

FAQ

Frequently Asked Questions

Are Cortizo Casement Windows more expensive than uPVC?

Yes, aluminium costs more upfront than uPVC — typically 20–40% more. But Cortizo frames last decades longer, need almost no maintenance, and add more value to your property. Over the lifetime of the windows, they usually work out as the better investment.

How energy efficient are Cortizo aluminium casement windows?

Very. Thanks to the 32mm thermal break, Cortizo casement windows achieve U-values from 1.0 W/m²K with double glazing and as low as 0.9 W/m²K with triple glazing. This meets and exceeds current UK Building Regulations and helps reduce heating bills noticeably.

What is the difference between flush and standard casement windows?

In a standard casement, the opening sash sits slightly proud of the outer frame. In a flush casement, the sash sits perfectly level with the frame, creating a smooth, flat appearance. Flush casements are popular for period properties and premium modern designs; both offer identical performance.

Are aluminium casement windows secure?

Yes. Cortizo Casement Windows are tested to British PAS 24 security standards and fitted with multi-point locking systems. Combined with toughened or laminated glazing options, they provide excellent protection for ground-floor and street-facing windows.

What colours and finishes are available?

You can choose from the full RAL colour palette — over 200 shades — plus anodised and textured finishes. Dual-colour options let you have one colour outside and another inside, so your windows match both your exterior and your interior style.

Do you install aluminium casement windows outside Croydon?

Yes. We’re based in Thornton Heath and install across Croydon, South London, and the wider London area. Contact us with your postcode and we’ll confirm coverage and arrange a free survey.