The Alitherm 400 system is the next generation of aluminium casement windows, combining slim, modern sightlines with outstanding thermal efficiency, enhanced security and long-lasting durability. Whether you're replacing existing windows, extending your home or building a new property, Alitherm 400 offers a stylish, low-maintenance solution that complements both contemporary and traditional architecture.
Designed for multiple window configurations, Alitherm 400 allows you to achieve the perfect look for your home.
Every window is bespoke manufactured to your exact specifications and is available in an extensive range of colours. Whether you're looking for a bold modern statement or a timeless classic finish, you'll find a style to suit your property.
Designed for Style, Security & Performance
Alitherm 400 Aluminium Windows offer:
• Slim, contemporary aluminium frames with elegant sightlines
• Double or triple glazing options
• Outstanding thermal efficiency with U-values as low as 1.2 W/m²K when triple glazed
• High-security multi-point locking systems
• PAS 24:2016 certified security for enhanced peace of mind
• Exceptional strength, durability and weather resistance
• Extensive range of colours
• Dual-colour options for different internal and external finishes
• Marine-grade finishes available for enhanced protection in coastal environments
• Virtually maintenance-free aluminium construction
With advanced thermal technology and high-performance glazing, Alitherm 400 windows help reduce heat loss, improve energy efficiency and create a warmer, quieter and more comfortable home throughout the year.
As proud members of Independent Network, qualifying installations carried out by Fernisky Frames are backed by an exclusive 10-Year Insurance Backed Guarantee, giving you complete confidence and peace of mind in your investment.
With over 30 years of experience, Fernisky Frames continues to provide homeowners across Ballymena and County Antrim with premium aluminium window solutions that combine cutting-edge design, exceptional performance and expert installation.
