Alitherm 400 Contemporary Aluminium Windows
Slim, modern aluminium windows with outstanding energy efficiency, security, and durability professionally supplied Nationally and installed across the north of England
Looking for slim, modern aluminium windows with A+ energy ratings?
Alitherm 400 contemporary windows offer outstanding performance, security, and durability — ideal for extensions, new builds, and contemporary renovations.
Aluminium windows that are safe, sustainable, and designed for a circular lifecycle — allowing materials to be reused or recycled rather than ending up as waste.
Key Features
Optimum thermal efficiency WER Rating A+
Incorporates innovative polyamide thermal break technology
Fully compliant with latest building regulations
PAS 24:2016 Approved
Dual Colour Possible
Unrivalled Choice of Colour
What Are Alitherm 400 contemporary windows?
Alitherm 400 is a premium aluminium window system designed for modern homes and renovations. Manufactured using advanced thermally broken aluminium frames, these windows deliver excellent insulation, security, and long-term durability — without bulky frames.
They’re ideal for:
- Home extensions
- New builds
- Replacement windows
- Modern renovations
- Large glazed openings
- Properties needing slim sightlines
Alitherm 400 Contemporary Windows
The Alitherm 400 contemporary window system
Designed for performance
Alitherm 400 uses advanced polyamide thermal break technology to create an insulating barrier between the inside and outside of the frame. This improves thermal performance, helps retain heat and supports compliance with current building regulations. The system is also designed to deliver excellent weather resistance, everyday durability and dependable home security.
Performance highlights
- Thermally broken aluminium frame
- Compliant with current Building Regulations
- PAS 24 security accreditation
- Suitable for double glazing and high-performance sealed units
VIEW THE COMPLETE CONTEMPORARY GLAZING COLLECTION HERE
Alitherm 400 Contemporary Windows
”Fantastic company, great product and extremely helpful throughout.”
Helen Westwell – Kendal, Cumbria
Window Styles Available
Alitherm 400 can be manufactured in a wide range of configurations to suit your home:
- Side-hung casement windows
- Top-hung windows
- Fixed picture windows
- Combination windows
- Large format glazing
- Flush or chamfered profiles
Whether you want a single replacement window or a full house transformation, the system is highly flexible.
Marston Lodge Farm – Vale of York
Due to sensitive planning restrictions the development required the retention of existing timber glazing to one of the properties.
As such the owners needed to ensure that new glazing to the remaining properties fully complied with conservation conditions and worked in harmony with the character of the buildings.
The local Council accepted the use of Marlin’s thermally efficient and secure Alitherm 400 windows.
COLOURS AND GLAZING
Your windows should work as hard visually as they do technically. Alitherm 400 is available in a wide range of durable powder-coated finishes, including dual-colour options for different internal and external looks. Combine your chosen frame finish with high-performance glazing to achieve the right balance of light, privacy, solar control and energy efficiency for your project.
the windows and doors look fantastic. Excellent service from initial contact through to delivery and beyond:-)”
Why choose Marlin?
Made for your project
Every window is manufactured to your required sizes and specification for a precise fit and a cleaner finish.
Quality at every stage
Our manufacturing process is carefully controlled to maintain consistent standards from order to delivery.
Support you can rely on
From your first enquiry through to installation and aftercare, we focus on clear advice, careful service and a result you’ll be happy to live with.
View our Alitherm 400 brochure
Ready to transform your home?
Get a made-to-measure quote for your Alitherm 400 Contemporary Windows today. Our team will guide you through sizes, styles and glazing options to find the perfect fit for your home.
Or call us on 01535 603909 to speak with our team.
Frequently Asked Questions
If you require any support, please don’t hesitate to review our FAQs below or drop us a message on our contact form here
What are Alitherm 400 Contemporary Windows made from?
Alitherm 400 windows are crafted from high-quality thermally broken aluminium. This material offers excellent strength, durability, and slim sight lines, while maintaining top energy efficiency through an internal thermal break that reduces heat loss.
Are Alitherm 400 windows energy efficient?
Yes. With thermally broken frames and high-performance glazing, they meet current UK energy standards and help reduce heat loss.
Can Alitherm 400 windows be used in both modern and traditional homes?
Yes. These windows are designed with versatility in mind. Their clean, slim profiles suit contemporary architecture, while the flush casement and chamfered options also complement more traditional or heritage-style homes.
How do I maintain and clean aluminium windows like the Alitherm 400?
Aluminium windows are low-maintenance. Regular cleaning with warm soapy water and a soft cloth is usually enough. Unlike timber, they won’t warp, rot, or need repainting, just an occasional check of seals and moving parts to ensure optimal performance.
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