Aluminium Windows

About Our Aluminium Windows Service

Aluminium windows offer a distinctly contemporary aesthetic that UPVC cannot match — ultra-slim sightlines, sharp profiles, and a wide range of RAL powder coat colours give a clean, architectural appearance that suits modern extensions, new-build homes, and commercial-to-residential conversions. Where UPVC's wider frame sections are perfectly acceptable in most domestic applications, aluminium's thinner profiles allow significantly more glass area in the same opening. At Red Lion Windows, we supply and fit thermally broken aluminium windows from reputable manufacturers. The thermal break — a strip of non-conducting material separating the inner and outer aluminium sections — is critical for residential use, as aluminium is naturally a strong conductor of heat. Without a thermal break, aluminium frames create cold bridging, causing condensation and heat loss. Our aluminium windows are specified with effective thermal breaks to deliver energy performance that meets current building regulations. Aluminium windows are available in any RAL colour, making it possible to match the window frames precisely to other aluminium elements on a building — bifold doors, curtain walling, or rainscreen cladding. For new-build properties or extensions where the architectural specification calls for a consistent metallic or anthracite finish, aluminium windows are the appropriate product. We supply and fit aluminium windows across Boston, Louth, Sleaford, and the wider Lincolnshire area. Contact us for a free survey and specification advice — we will confirm whether aluminium or UPVC is better suited to your project before taking any measurements.