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Citi Homes Windows

Casement Windows

The most popular window style in the UK.

Casement windows are the most widely specified window type across the UK and have been a staple of British architecture since the medieval period. Hinged at the side and opening outward like a door, they suit almost every property type – from Victorian terraces and Edwardian semis to contemporary extensions and new builds across London. They are versatile, highly energy efficient, easy to operate and available in a wide range of materials, styles and finishes.

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What is a casement window?

Casement window by Origin

A casement window is a window that is attached to its frame by one or more hinges, usually at the side, and opens outward using a handle or crank mechanism. Unlike a sash window, which slides vertically, a casement window swings open to allow maximum ventilation. When closed, the sash presses firmly against the frame, creating a tight draught-resistant seal that makes casement windows one of the most thermally efficient window types available.

Casement windows have been installed in British homes for centuries and remain the most common choice today because of their practicality, adaptability, and clean appearance. Modern casement windows are significantly more advanced than older designs, with improved glazing, sealing systems, multi-point locking, and slimmer profiles available across all material types.

Types of casement windows

We work with leading manufacturers and brands to supply a full range of casement window styles for London homes:

  • Side-hung casement windows

    The standard casement, hinged at the side and opening outward. Available as a single sash or paired as a double casement in one frame. The most widely used window type across London properties.

  • Flush casement windows

    The sash sits flush with the outer face of the frame, creating a flat, seamless appearance. Particularly popular for period properties, conservation areas and heritage-sensitive projects where a traditional timber look is required.

  • Top-hung casement windows

    Hinged at the top and opening outward from the bottom. Ideal for upper floors, bathrooms and rooms where privacy is needed but ventilation is still important. Often combined with a fixed light below.

  • French casement windows

    A paired casement with no central mullion, opening fully outward from the centre. Creates a wide, unobstructed opening and works beautifully as a garden-facing or balcony window. Also known as french windows.

  • Tilt and turn windows

    Technically a casement variant, hinged at the side for full opening and at the bottom for tilt ventilation. Popular in contemporary London homes and upper-floor installations where safe cleaning from inside is essential.

  • Fixed light casement windows

    A non-opening sash set within a casement frame, used alongside opening lights to maximise glass area. Common in large glazed walls, stairwells and contemporary extensions.

The brands we work with

Brand of windows - Velfac
Brand of windows - ORIGIN
Brand of windows - Schuco
Brand of windows - Reynaers
Brand of windows - Cortizo
Brand of windows - Rationel
ALUK logo
Smart architectural aluminium logo
Alunet systems logo

Benefits of casement windows

Casement windows remain the most popular window type in the UK for a reason. Here is why homeowners and architects continue to specify them:

  • Maximum ventilation

    The full sash opens outward, allowing more airflow than any other hinged window style. Ideal for kitchens, living rooms and bedrooms.

  • Excellent energy efficiency

    When closed, the sash compresses tightly against the frame seal, minimising draughts and heat loss. Compatible with double and triple glazed window units.

  • Strong security

    modern casement windows use multi-point locking systems embedded within the frame. All windows we supply can be specified to PAS 24 security standards.

  • Versatile design

    Available in side-hung, top-hung, flush and French configurations to suit any room, elevation or architectural style.

  • Slim sightlines

    Modern profiles in aluminium and composite offer very slim frames, maximising the glass area and light entering the room.

  • Easy to clean

    The sash opens fully outward, making it straightforward to clean both faces of the glass from inside the property on most ground and first-floor installations.

  • Wide material choice

    Available in aluminium, timber and composite, meaning casement windows can be matched precisely to the character of the property and the performance requirements of the project.

  • Low maintenance

    Particularly in aluminium and composite, where the exterior requires little beyond occasional cleaning.

  • Suitable for most room types

    Kitchens, bedrooms, living rooms, bathrooms and studies all benefit from the ventilation and light a casement provides.

When casement windows are the right choice

Current aluminium window systems use thermal breaks and modern glazing to support comfortable indoor temperatures and good acoustic performance. There is scope to choose glazing according to how each elevation is exposed to weather and noise.

  • Victorian, Edwardian and Georgian properties – flush casements in timber or composite replicate original profiles accurately and are widely accepted by planning authorities and conservation officers.

  • Contemporary extensions and new builds – slim aluminium casement windows complement modern architecture and offer maximum glass area with minimal frame.

  • Side and rear elevations – where full ventilation and ease of opening are priorities.

  • Ground and first-floor rooms – where outward opening is practical and safe.

  • Conservation areas and listed buildings – flush timber or composite casements can be specified to match original window details and support planning consent applications.

  • Rooms needing good natural ventilation – kitchens, bathrooms and bedrooms benefit particularly from the full-opening casement design.

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Available in a range of materials

  • Aluminium casement windows

    Slim, durable and low maintenance. Available in a full RAL colour range with powder-coated or anodised finishes. Ideal for contemporary London architecture and extensions. Brands we work with include Reynaers, Cortizo and Schüco.

  • Timber casement windows

    The traditional choice for period properties and conservation areas. Available in engineered redwood, oak, Accoya and other hardwoods. Factory finished using microporous paints and stains.

  • Composite casement windows

    Combine a natural timber interior with a durable aluminium exterior. Outstanding thermal performance, minimal maintenance and available from Velfac, Rationel and Schüco.

Aluminium windows
Timber windows
Composite windows

Finishes, hardware and security

Finishes & colours

Casement windows are available in a full RAL colour range across all material types. Dual colour finishes, with a different shade inside and out, are popular across London renovations, keeping a classic white or timber tone inside whilst using an anthracite grey, black, or sage green externally.

All casement windows we supply are available with:

  • Double glazing – the standard choice for most London homes, meeting current building regulations for thermal performance and covering most double glazing windows near me requirements.

  • Triple glazing – triple glazed window units for positions near busy roads, rail lines or where enhanced acoustic and thermal performance is needed.

  • Acoustic glass – laminated units for noise-sensitive urban locations.

All casement windows are fitted with multi-point locking mechanisms, with handle styles ranging from traditional cockspur and monkey tail designs to contemporary bar handles and espagnolette systems. Restrictors, child safety locks and night vent positions are available on request. All windows can be specified to PAS 24.

FAQ

A casement window is hinged at the side and opens outward like a door. A sash window slides vertically within the frame. Sash windows are typically associated with Georgian and Victorian period homes on principal elevations, whilst casement windows are more versatile and widely used across all property types and elevations.

Yes, in many cases. Flush casement windows in timber or composite, with slim profiles and glazing bar details, are widely accepted by local planning authorities in conservation areas across London. We recommend checking with your local authority before ordering.

Quality casement windows in aluminium or composite typically last 40 years or more with minimal maintenance. Timber casement windows with quality factory finishes can last 50 years or more when maintained correctly. All windows we supply come with a manufacturer's warranty.

Like-for-like replacements generally do not require planning permission in standard residential properties. However, properties in conservation areas or listed buildings may require prior approval or listed building consent. 

Double glazing window costs for casements vary depending on the material, size, glazing and specification. Aluminium is typically the most competitively priced premium option, whilst timber and composite sit higher depending on the system chosen. Contact us for a tailored windows installation price.

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