Strength and security are important factors to consider when replacing old windows or adding them to an extension, renovation or new build. However, it’s important not to forget the functionality and aesthetics of the window. For example, you may be required to add a fire escape window to your property, or from a design front, you might simply want to install windows that complement the existing character of your home whether it be modern or traditional.
It can be tough knowing what window style to go for, especially when you need to consider current building regulations, thermal efficiency and security features. French windows and casement windows are two practical options that allow lots of natural light into your home, however, they operate slightly differently.
Below, we compare key features of the Origin French Window with a standard left and right opening casement window.
In this guide:
Two side-hung casements that open with a moving mullion, offering an unobstructed view.
Side or top-hung windows with versatile designs, often mistaken for French windows.
French windows give clear views and wide openings; casement windows offer more options.
French windows offer wide open views; while, casement windows offer greater flexibility.
What is a French window?
A French window should not be confused with a French door, although the mechanism is very similar. French windows feature two casements (or panels of glass) that are side hung and open outward. The mullion - the aluminium profile in the middle of the French window - isn’t fixed. Instead, it locks into and opens with one of the panels to create an uninterrupted view when opened, as shown below.
What is a Casement window?
Find your local installer today to bring your vision to life
Casement windows are side or top-hung windows. Sometimes, top hung casement windows are referred to as awning windows.
A pair of left-hung and right-hung casement windows can often be mistaken for a French Window, however, with a casement window, the mullion remains in place when open.
Comparison between Origin French Windows and Origin Casement Windows
| Origin French Window | Origin Casement Window | |
|---|---|---|
View | The Origin French Window can provide a completely unobstructed view as the mullion (a vertical bar found between the sashes in the window) isn't fixed. This means the window can open up entirely. Friction hinges also allow you to leave your French windows open as far as you like. | When there are two casement windows together and they are both open, the mullion remains at the centre of the opening. This results in a view that is partially obstructed by the central post. |
Security | Highly secure, the Origin French Window features shoot bolts, friction hinges and a unique multi-point locking system, fully integrated to support the moving mullion. The window is PAS 24 certified and also features high-grade stainless steel hinges. All of these parts fall under Origin's industry-leading guarantee of up to 20-years. | The Origin Casement Window offers high-grade stainless steel hinges, hinge guards, a multi-point locking system, locking handles and crimped frames. It's one of the most secure windows on the market today, PAS 24 certified and can be specified to be Secured by Design. It has been cycled tested to surpass residential window regulation requirements. |
Safety | Meeting current building regulations, the Origin French Window can be used as an emergency exit window. | Side or top hung casement windows that meet the minimum height and width requirements, according to current building regulations, can be used as emergency exit windows. |
Configuration | Coming in just one configuration, the French window features two sashes that are side hung and open outwards. | Casement windows come in a wide variety of configurations – whether it be top or side hung. Fixed frame windows can also be used to make up your desired configuration. |
Property suitability | A modern take on a traditional design, aluminium French windows can suit both old and new properties. Georgian-style astragal bars can be used to create a grid effect to match the style of an older property. You can choose between 150 RAL colours, and on the OW80, woodgrain options are available. | Suitable for both old and new properties, aluminium casement windows are versatile. Origin offers a range of choices, including Soho-inspired glazing divides on the OW70 or astragal bars to create grid patterns on the OW80, or uninterrupted glazing to create a Gallery aesthetic. In addition to 150 RAL colours, you can choose contrasting internal and external shades, and woodgrain finishes are available on the OW80. |
Strength | Made from premium-grade aluminium for superior strength, Origin French Windows and Casement Windows are extremely strong yet weigh 67% less than steel. | |
Thermal efficiency | Origin French Windows can achieve a U-Value of 0.8W/m²K with triple-glazing and Aerogel. Find out more with our energy efficiency FAQs. | Origin’s premium Casement Windows (OW80) can achieve a U-Value of 0.8W/m²K with triple-glazing and the world’s best insulator - Aerogel. |
Lead times | 2-weeks for popular colours and 3-weeks for all other RAL colours. | The average lead time in the industry is 5-8 weeks. However, Origin offer a 'Your Lead Time, Not Ours' promise, meaning you can get your casement windows in as little as 24-hours depending on the colours and finishes you choose. |
Colours | 150+ RAL colours available, including woodgrain and dual colour options (only on OW80). On the OW70, textured options are available. | |
Sizes | All Origin products are entirely bespoke and custom made, meaning we make your windows to your specifications. An Origin French Window can be manufactured up to 1800mm wide and 1,400mm tall. | Individual side hung casement windows can be manufactured up to 1,000mm wide and 1,800mm tall. Individual top hung casement windows can be manufactured up to 1,500mm wide and 1,500mm tall. |
Guarantee | The average guarantee across the industry is 10-years, however, Origin offers an industry-leading guarantee of up to 20 years, which covers all hardware and components as well as the powder coating finish. | |
Which is better, French windows or casement windows?
Casement windows are ideal for homeowners looking for versatility, configuration flexibility and broader style options. Casement windows are available with two window sightlines 70mm (OW70) and 80mm (OW80). Casement windows can be customised with glazing bars (either true divides or stuck on) to create a Georgian style or an industrial aesthetic.
On the other hand, French windows provide the most uninterrupted view of the outdoors. There is only one configuration option for the French window, but you can choose your required dimensions, RAL colour and even add astragal Georgian bars for a heritage look. French Windows are only available with the OW80.
Choose the French window if you value wide openings and uninterrupted views. However, casement windows are more versatile and allow for more personalisation.
Are French windows more expensive than casement windows?
Due to the innovative design of the French window's floating central mullion, they can cost slightly more than an equivalent pair of left and right-opening casement windows. However, for the natural light and expansive views when open, it can be worth the additional expense.
Are French windows or casement windows more energy efficient?
All Origin Windows offer ahead-of-the-curve energy efficiency. Our modern window designs prevent heat loss due to a tight seal, thermal breaks, and the option of choosing triple or double-glazing.
The French window is only available on the OW80 system, and therefore, both casement and French windows are able to achieve the same energy efficiencies and U-Values (0.8).
Traditional French windows with a timber frame would likely increase your energy consumption.
Premium aluminium window frames use modern materials to balance elegant design, thermal performance, and security. There is a range of options and configurations to choose from, such as hung casement windows, French windows and Georgian-style Window designs.
Which type is better for ventilation: French windows or casement windows?
French windows provide a wide opening because the central post (or mullion) is not fixed. However, this feature doesn't significantly affect the ventilation available with casement windows. Trickle vents and night vents are helpful options for ensuring maximum ventilation while the windows remain closed and secure.
The French window design can provide a lot of natural light and a sense of space, creating a more seamless transition with the outdoors.
Window security: comparing lock mechanisms and safety
It is a myth that French windows are less secure than casement windows because they don't have a fixed central mullion. However, Origin Windows feature shoot bolts, friction hinges and a unique Multi-Point locking system. These features keep you and your family safe with no compromise.
Frequently Asked Questions
Are casement windows the best type of window?
There is no perfect window type. However, casement windows are among the most versatile. There are many configurations and customisation options to suit modern homes and period properties. There is a range of alternative window types, such as sash windows and tilt-and-turn windows.
Which window is better: aluminium or uPVC?
Both materials have their merits: uPVC French windows are durable, but they can discolour and lose alignment over time. Additionally, they may not look as refined as other materials. Aluminium, on the other hand, is a bigger investment, but balances visual appeal with slimmer sightlines, a cleaner finish, elegance, durability, security and performance.
Which window style offers a wider opening: French or casement?
French windows provide a wider open space than a pair of side-hung casement windows because the mullion travels with the window when open, rather than remaining a fixed component of the window frame. Because French windows open widely, they can reliably be used as an emergency fire exit.
