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Citi Homes Windows

Smart windows

Alitherm Heritage aluminium windows

Casement and tilt & turn windows

Slim, steel‑look aluminium windows designed for heritage, conservation and listed buildings, offering modern thermal performance while closely matching traditional steel sightlines. Ideal for Victorian and Art Deco properties across London.

Open out casement window. Smart Systems
Tilt and turn window. Smart Systems

Alitherm Heritage windows are engineered specifically for sensitive refurbishment and renewal projects, especially in areas with strict planning requirements. Their thermally broken aluminium profiles deliver typical U‑values around 1.5 W/m²K with suitable double glazing, helping to reduce heat loss and condensation compared with original steel or timber frames. The system has been used extensively in UK heritage projects and approved by multiple local authorities, providing a modern, like‑for‑like replacement that respects original design while improving comfort, security and lifespan. For London property owners, this means authentic appearance, long service life and minimal maintenance, backed by Smart Systems’ decades of aluminium expertise.

  • Opening types: fixed panes, side‑hung casement, top‑hung casement, tilt & turn, pivot windows and multi‑part horizontal modules.

  • Typical frame depth: around 47 mm.

  • Glazing thickness: accommodates approx. 24–36 mm double‑glazed units.

  • Performance: Window Energy Rating B; U‑values around 1.5 W/m²K with suitable sealed units; air tightness Class 4; water tightness Class 9A; wind resistance Class AE; tested to BS 6375 and PAS 24 (enhanced security).

  • Example design limits: side‑hung vents up to roughly 700 mm wide x 1400 mm high; top‑hung vents up to roughly 1400 mm wide x 1300 mm high; maximum vent weight around 40 kg.

Thermally broken aluminium profiles with polyamide insulation, providing excellent strength, durability and corrosion resistance. Powder coated finishes are marine‑quality for long‑term colour stability, even in exposed urban or coastal environments.

Double‑glazed units in a range of thicknesses (typically 24–36 mm), configurable for energy efficiency, acoustic control or specific heritage requirements. Glazing can be specified to meet planning, acoustic and performance needs of each project.

Available in single or dual powder coated finishes, including Smart Naturals, full RAL range, Sensations textured colours and Alchemy anodised‑look tones (bronze, silver, grey, black and more). Dual‑colour options allow different internal and external colours to suit heritage design and interior schemes.

Citi Homes Windows installs Alitherm Heritage windows under Smart Systems’ manufacturer warranty, covering profiles, finishes and system performance when fabricated and fitted in line with Smart’s installation guidance.

Examples of Alitherm Heritage windows

Alitherm 400 aluminium windows

Casement and tilt & turn

Versatile aluminium windows for London homes, schools and commercial buildings, combining class‑leading thermal performance, PAS 24 security and a wide choice of casement and tilt & turn configurations.

Alitherm 400 casement window. Smart systems
Alitherm 400 tilt and turn window. Smart systems

Alitherm 400 is Smart’s modern, everyday aluminium window system designed to meet strict Building Regulations while offering outstanding value. Fully compliant with Part L, it delivers typical U‑values around 1.4 W/m²K and Band A Window Energy Ratings with suitable glass, making it ideal for both new build and refurbishment. The system supports fixed windows, side‑hung and top‑hung casements, flush casements and tilt & turn options, so architects and homeowners can choose the layout that suits each room and elevation. Smart’s Quick‑Glaze Bead and co‑extruded gaskets simplify fabrication and installation, helping to keep fitting times and disruption down on London projects, while maintaining consistent long‑term performance.

  • Opening types: fixed, side‑hung casement, top‑hung casement, flush casement, tilt & turn.

  • Frame depth: approx. 70 mm.

  • Glazing thickness: accepts around 24–45 mm units, including high‑performance double and triple glazing.

  • Example maximum sizes (illustrative): side‑hung sashes up to about 864 mm x 1400 mm; top‑hung sashes up to about 1400 mm x 1400 mm; fixed windows up to around 2100 mm x 2100 mm; tilt & turn units up to roughly 1200 mm x 2100 mm.

  • Performance: typical U‑values around 1.4 W/m²K with suitable sealed units; Window Energy Rating Band A; air permeability Class 4; water tightness E1200; wind resistance AE2400; security tested to PAS 24:2022.

Thermally broken aluminium profiles with integrated, co‑extruded gaskets for reliable weather performance. Aluminium offers excellent strength, slim sightlines and minimal maintenance compared with timber and uPVC alternatives.

Wide glazing range from approx. 24–45 mm, accommodating standard double glazing, acoustic units and higher‑specification glass to meet project requirements, including improved thermal and sound insulation.

 

Extensive colour palette including standard and bespoke RAL finishes, Sensations textured colours and dual‑colour options for contrasting internal and external aesthetics. This allows Alitherm 400 windows to complement both modern and traditional facades.

Smart Systems’ manufacturer’s warranty covers Alitherm 400 windows supplied and fitted by Citi Homes Windows for the system, profiles and finishes, when installed to Smart’s specifications.

Examples of Alitherm 400 aluminium windows

VS600 sliding sash windows

Vertical sliding aluminium sash windows designed to replicate traditional timber sash aesthetics, while delivering modern performance and low maintenance for London period homes.

VS600 Smart window technical information

VS600 sliding sash windows provide a contemporary aluminium solution for properties that traditionally rely on timber sash windows, such as Victorian and Edwardian terraces across London. The system offers classic vertical sliding operation with slim profiles and modern locking, while benefiting from thermally broken aluminium and durable powder-coated finishes. This significantly reduces painting and upkeep compared with timber frames and allows the use of double‑glazed units for improved comfort and energy efficiency. For homeowners seeking sympathetic upgrades in period streets, VS600 combines a familiar look with modern durability and performance.

  • Opening type: vertical sliding sashes, with top and bottom sashes movable depending on specification.

  • Operation: smooth sliding balances and robust locking designed for sash windows.

  • Multi‑chamber aluminium profiles with thermal breaks for improved insulation and rigidity.

Thermally broken aluminium sash profiles designed to mimic timber sash proportions while delivering higher durability, corrosion resistance and reduced maintenance.

Compatible with double‑glazed sealed units, enabling improved thermal and acoustic performance over traditional single‑glazed timber sash windows.

Available in standard and bespoke powder-coated colours, including heritage tones to match existing facades, and dual‑colour options where different internal and external colours are desired.

VS600 windows installed by Citi Homes Windows are supplied under Smart Systems’ manufacturer warranty for their sash system, profiles and finishes, when fabricated and fitted according to Smart’s guidelines.

Examples of VS600 sliding sash windows

Book your Smart aluminium window survey

For Smart aluminium windows in London – including Alitherm Heritage, Alitherm 400 and VS600 sash windows – Citi Homes Windows provides full surveys, supply, and professional installation. Contact us to discuss your project, send drawings or book an on‑site visit.

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