Sheerline Windows
Welcome to the Sheerline aluminium window collection, proudly supplied and installed across Andover, Hampshire, and the surrounding areas of Southern England by KJM Group. Designed and manufactured entirely in Britain, Sheerline represents the next generation of aluminium glazing. By combining patented construction techniques with exceptional thermal engineering, this highly advanced system eliminates the common compromises associated with older aluminium frames. Whether you are replacing traditional steel windows or designing a light-filled contemporary extension, Sheerline delivers ultra-slim sightlines, robust security, and outstanding energy efficiency.
Why choose Sheerline for your Windows?
Sheerline Benefits
The core advantage of choosing Sheerline is its innovative Thermlock® multi-chamber technology. Hidden inside every frame, these closed-cell insulating chambers provide a thermal break that is far superior to traditional polyamide strips, easily achieving Part L compliance and U-values as low as 1.1 W/m²K. Furthermore, Sheerline utilises a patented corner construction method that uses threaded screws to bind the corners tightly together. This eliminates the misaligned joints often seen on standard aluminium frames, ensuring a perfectly flush, hand-tuned finish. For complete peace of mind, Sheerline products are sustainably manufactured from highly recycled aluminium and come with a comprehensive 25-year guarantee covering profile integrity, thermal performance, and the powder-coated finish.
Classic, Prestige or Heritage?
Sheerline Window Options
The Sheerline window collection is divided into two distinct systems to suit your specific architectural requirements. The Classic system is an ultra-slim profile featuring sightlines of just 59mm for opening sashes. It is the perfect replacement for traditional steel Crittall windows, offering authentic heritage bars and a revolutionary beadless option for unrivalled aesthetics and enhanced security. The Prestige system is a highly versatile, 72–80mm deep profile that accommodates casement, French, and tilt-and-turn styles. Available with a choice of flush or standard outer frames, Prestige is designed to maximise the glass area in modern properties while delivering up to an A+ Window Energy Rating. Explore both ranges below to view custom configurations and our extensive palette of matt, gloss, and metallic powder-coated finishes.
Sheerline Brochures
Frequently Asked Questions
What is Thermlock® technology and how does it differ from a standard thermal break?
Traditional aluminium windows use a rigid polyamide plastic strip to separate the inner and outer metal frames to prevent heat loss. Sheerline’s proprietary Thermlock® technology replaces this with a bespoke, multi-chambered closed-cell material. This advanced design traps more air, resulting in significantly better insulation, higher energy ratings, and warmer rooms during the winter months.
What is the difference between the Sheerline Classic and Prestige systems?
The primary difference is the frame depth and sightlines. The Classic system features an ultra-slim 59mm sightline designed specifically to replicate traditional steel windows or provide a highly minimalist contemporary look. The Prestige system uses a slightly deeper 72–80mm profile that accommodates a wider range of window styles, including tilt-and-turn options, and offers slightly higher peak thermal efficiency for larger glass expanses.
What does Sheerline's 25-year guarantee actually cover?
Because Sheerline manufactures the extrusion and thermal components themselves in the UK, they provide a very robust 25-year guarantee. This covers the structural integrity of the aluminium profile, the performance of the Thermlock® insulation, and the durability of the factory-applied powder-coated finish against peeling, blistering, and corrosion (subject to standard maintenance).
What is a 'beadless' window and why does it improve security?
On a standard window, the glass is held in place by ‘beads’ (strips of material clipped into the frame). While modern beaded windows are secure, the Sheerline Classic system offers a revolutionary beadless option where the glass is secured directly within the internal structure of the frame. This completely eliminates the glazing bead, removing a common point of attack for intruders and providing incredibly clean internal lines.
How do I maintain Sheerline aluminium windows?
Sheerline windows are designed to be exceptionally low maintenance. The marine-quality powder coating will not fade, warp, or rust. To keep them looking their best, you simply need to wipe the aluminium frames down periodically with warm, soapy water to remove environmental dirt. You should also lightly lubricate the hinges and locking mechanisms a few times a year to ensure smooth operation.
Why choose KJM?
Get Your Free Quote Today
Since 1983, KJM Group has been installing high-quality glazing solutions across Hampshire and the surrounding areas. As an independent, award-winning Which? Trusted Trader, we pride ourselves on delivering honest advice, transparent pricing, and a strict no-pressure sales policy.
Installing architectural aluminium requires precise surveying and exact fitting tolerances. Our experienced, in-house installation team ensures every Sheerline frame is fitted flawlessly, respecting your home throughout the process. From the initial consultation through to our comprehensive aftercare service, we provide a reliable, professional experience that ensures your new windows perform exactly as they should for decades to come.