What is a casement window?


Everything you need to know including how casement windows work and the key benefits they provide for any type of property.

What is a casement window? What is a casement window?

Believe it or not, casement windows have been an architectural feature in Britain a lot longer than the classic sliding sash window has. Usually fitted singly or in pairs, casement windows are functional, versatile and airtight. So, it's hardly surprising that these windows remain one of the UK's favourite window styles, thanks to their simplistic yet secure nature.

Available in every window material and either sculptured (curved) or chamfered (symmetrical) frames, casement windows hold the power to enhance traditional, heritage and new build properties alike. Their low maintenance qualities also appeal to the 21st-century property owner, beautifully enhancing the busiest of lifestyles.

What is a casement window?

Casement windows effectively ventilate any location they're applied to, thanks to their typical side-hinged positioning. Incredibly adaptable, casement windows can also be hinged to open out from the top or bottom of the window frame; AKA 'awning windows' (top opening) and 'hopper windows' (bottom opening).

How does a casement window work?

Most commonly hinged at the side of the window frame and configured to swing outwards, casement windows are held open with a traditional casement stay or a modern casement friction hinge or crank mechanism. Designed to acclimatise to any style of property, bespoke casement windows from Everest can be manufactured and installed to open inwards too.

What are the parts of a casement window?

It's important to get to grips with your new windows; to fully respect them, you must fully understand them first.

  • Window Frame - The window frame holds the casement window in place. It is made up of a head and a sill that runs horizontally along the top and bottom, combined with two jambs that run vertically on either side.
  • Window Sill - Forming the bottom of the window frame, window sills are slanted to effectively direct water away from the window frame and the building.
  • Casement - The casement is the part of the window that opens, securing the double or triple glazing in place via a hinge fixed to the side, the top or bottom of the window frame.
  • Mullion - A window mullion is the vertical strip of supporting uPVC, timber or aluminium that divides separate window units, e.g. the part that separates an opening casement window and a fixed pane window.
  • Transom - A window transom is the horizontal strip of supporting uPVC, timber or aluminium that divides separate window units, e.g. the part that separates a fixed pane window and a vent window.
  • Lock Handle - The casement window's locking mechanism is located on the casement jamb. There are many styles and colours to choose from, to make your new casement windows as unique as you are.
  • Trickle Vent - Depending on the room you're revamping, trickle vents can be added to casement windows to increase ventilation and prevent condensation. Fitted at the top of the window, trickle vents consist of a grill on the outside and a closing vent on the inside.
  • Georgian Bars - Fitted inside the sealed unit, Georgian bars are the vertical and horizontal bars that create the classic appearance of the glass being divided up into small squares; just like the Georgians did in the 18th Century.
  • Astragal Bars - Similar to Georgian bars, Astragal bars are applied to one single piece of glazing; fitted on top of the window, internally and externally.

Are casement windows more expensive?

The price of your new casement windows depends on a number of factors, most notably;

  • Quality
  • Performance
  • Material
  • Style
  • Glazing
  • Finish
  • Hardware

At Everest, we don't show prices because we firmly put you in control from the outset.

Read about window pricing

What is a fixed casement window?

Fixed casement windows are used for decoration within casement window layouts. Enhancing far-reaching views whilst flooding rooms with natural light, fixed casement windows are generally accompanied by fully opening casement windows on each side, and are particularly popular with bay window arrangements.

What is a casement picture window?

A picture window is a large rectangular window that cannot be opened, overlooking an appealing view. Usually flanked by fully functioning casement windows, the average picture window size begins at 12 inches in height and width, increasing by increments of 6 inches e.g. 18 inches, 24 inches, 30 inches, etc.

Are casement windows better?

Although this question relies heavily on the type of property you have, if you're basing your choice on energy performance only, it's particularly interesting to note that the casement window seal is much more airtight than a sliding sash window seal. This is due to the way each window opens, with sliding windows requiring a fairly flexible seal for ease of opening. Whereas casement windows are not flexible by design and can, therefore, form airtight seals which effectively keep more heat inside; markedly reducing energy bills and saving money further down the line.

Is it worth replacing windows before selling a house?

It goes without saying that replacing windows before selling a house will make your home much more appealing to home buyers; after all, secure windows are a crucial feature that buyers seek in their new home. By smartening up the exterior of your home with new windows, you could add anywhere between 5-10% onto your homes resale price. Even better, by paying close attention to your homes Energy Performance rating (EPC), you could potentially boost your property value by a further 6-14% with proactive home improvements like new casement windows.

Fit the best casement windows with Everest

We hope this blog has helped to settle your thought process and make an informed choice to upgrade the windows in your home. Are you interested in Everest's casement windows? Work out how much your casement window replacements will be, by requesting a free no-obligation quote today. Discuss anything further with one of our experts, who will be happy to show you samples and provide an accurate price.

Related to this topic: What is a flush casement window?

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