The Independent’s journalism is supported by our readers. When you purchase through links on our site, we may earn commission. Why trust us?

Flush casement windows guide

Get Free Windows Quotes
Compare quotes to get the best price on your new windows
Do you rent or own your home?

Flush casement windows are increasingly popular with homeowners wanting to give their homes a contemporary style. However, while they boast a modern look, this design has been a staple in the UK since the 16th century and can be seen in numerous historic properties across the country.

They have also significantly influenced Scandinavian architectural designs and, today, offer homes the highly desirable Scandi chic, minimalist look. 

If you’re considering new flush casement windows, our experts guide you in the right direction, providing insights into the diverse customisable options currently available, the costs, and the best ways to obtain favourable quotes.

Complete our short form to request windows quotes for your home

Get free, no obligation quotes from up to 4 local windows installers

Compare quotes and pick the option that best suits your needs

What type of windows do you need?
It takes just 60 seconds

What are flush casement windows?

White uPVC flush casement windows
Easy to clean, white uPVC flush casements contrast beautifully against the weathered red bricks (Everest)

The defining feature of flush casement windows is that the window frame sits flush within the outer frame when closed, with hidden hinges, creating a smooth, flat surface. This contrasts with typical casement windows, where the window protrudes or sits slightly above the frame line. The flush design offers a sleek and elegant appearance, lending itself well to both period and modern homes.

Traditionally, these types of windows were made from timber, contributing to their historical charm and providing a classic, timeless look. However, advances in materials and design have led to the availability of flush casements in various styles, including uPVC and aluminium double glazed windows, combining traditional aesthetics with modern durability and energy efficiency.

The versatility in design and materials makes flush casement windows a popular choice. They allow for a range of customisations in terms of colour, finishing, and glazing options, enabling them to suit any style of home. Moreover, these windows offer practical benefits, such as improved insulation and security, while maintaining an aesthetic that enhances a house’s interior and exterior appearance. Their ability to blend seamlessly into the structure of a building makes them a sought-after choice for those looking to maintain or enhance the character of their property.

Advantages of flush casement windows

Flush casement windows offer a range of advantages that make them a popular choice among homeowners:


Energy efficiency

When equipped with double glazing, flush casement windows improve a home’s insulation. The gap between the two glass panes in double glazed windows acts as an insulating barrier, reducing heat loss and saving on energy bills


Eliminates draughts

Due to the tight-fitting flush design, draughts are eliminated


Improved ventilation

The design of flush casement windows allows them to open much wider than standard casements


Improved security

Typically, flush casements include more advanced, multi-point locking mechanisms. Their design also has fewer leverage points compared to standard casement windows


Aesthetic appeal

With their clean lines and flush finish, these windows offer a sleek, elegant look that complements both traditional and contemporary homes. The design is particularly suited to period properties or those seeking a classic style


Noise reduction

The solid construction and tight seals of flush casement windows, especially when double glazed, help to reduce outside noise, making them ideal for homes in busy or urban areas


Low maintenance

Modern materials, such as uPVC or aluminium, require minimal maintenance. They don’t need painting or treating like traditional timber frames and are easy to clean


Conservation friendly

Flush windows meet the requirements for most conservation areas in the UK

Disadvantages of flush casement windows

While flush casement windows offer many benefits, there are also some disadvantages to consider:



The sophisticated design used in flush casement windows can lead to higher costs, typically 10 per cent more than standard casements


Installation complexity

The installation of flush casement windows can be more complex due to their design, potentially increasing installation costs


Replacement parts

Finding replacement parts or doing repairs to flush casements might be more challenging or expensive


Limited glazing weight

Due to being fully openable, flush casement windows are limited in the glazing weight they can carry

How much do flush casement windows cost?

The cost of new windows varies depending on the material, style, and finish you choose. However, they typically cost around 10 per cent more than standard casement windows. 

The table below shows the average price you can expect to pay for flush casement windows.

Flush casement window material 600mm x 900mm 900mm x 1,200mm 1,200mm x 1,200mm
uPVC £550 £640 £700
Aluminium £1,154 £1,300 £1,420
Timber £1,700 £1,920 £2,100

Flush casement window materials and styles

Flush casement uPVC windows

Cream uPVC flush casement windows
Cream uPVC flush casement windows offer a stylish contemporary look to this pretty cottage (Anglian)

Unplasticised polyvinyl chloride, commonly known as uPVC, is a widely used material in constructing window frames, including flush casement designs. It’s favoured for its durability, minimal maintenance requirements, and excellent insulation, helping reduce heating costs and noise pollution in your home. 

Additionally, uPVC’s versatility allows for various window designs and colours, making it adaptable to different architectural styles. Despite being a plastic derivative, uPVC is recyclable, which adds an aspect of environmental consideration to its use in window manufacturing.

Generally, uPVC windows are more affordable than those made with alternative materials like wood or aluminium. 

Aluminium flush casement windows

Aluminium flush casement windows are known for their strength and resilience. This material can withstand harsh weather conditions, resist corrosion and rust, and maintain its integrity over time. It’s also highly recyclable, which adds to its environmental appeal. Aluminium windows can be recycled repeatedly without losing quality, reducing their carbon footprint.

Aluminium is particularly suitable for large, wide, or tall window designs due to its structural strength. 

Wooden flush casement windows

Timber flush casement windows
Timber flush casement windows (Anglian)

Wooden flush casement windows have a classic, timeless beauty that adds warmth and character to any building. The natural grain patterns in wood provide a unique, elegant appearance, and being a renewable resource when sourced sustainably, it’s an eco-friendly option. Wooden windows can also be recycled at the end of their lifespan.

Wood is a natural insulator, helping to keep homes warm in winter, leading to improved energy efficiency and reduced heating costs, while its natural density makes it effective at reducing noise pollution, providing a quieter indoor environment.

However, it’s important to note that wooden flush casements require more maintenance than uPVC or aluminium windows. They need regular painting or varnishing to protect against weathering, rot, and pests. Despite this, for many, wood’s aesthetic and natural qualities make it a worthwhile choice.

Composite flush casement windows

Composite windows combine the classic look of wood inside with the modern appeal of uPVC or aluminium on the outside. This versatility makes them suitable for a wide range of architectural styles, including flush casement windows. 

The combination of materials in composite windows results in a highly durable product that can withstand various weather conditions, resist rot and decay, and maintain its integrity over time. 

Composite windows offer excellent insulation. The wooden interior provides natural insulation, while uPVC or aluminium reduces heat loss on the exterior, leading to better energy efficiency in homes. 

Composite windows offer the best of both worlds – the natural warmth and beauty of wood on the inside and the strength, durability, and low-maintenance material on the outside. This makes them a preferred choice for those looking for a combination of performance, aesthetics, and environmental considerations.

Flush casement bay windows

Flush casement bay windows
Flush casement bay windows combine the charm of the bay design with a sleek, modern window frame (Adobe)

Bay windows extend outward from the wall of the building, creating a bay or alcove within the room. They typically consist of a central window flanked by two angled side windows. Incorporating a flush design means each bay window section is a flush casement, sitting neatly within its frame. 

This design not only enhances the aesthetic appeal of the building but also allows for more natural light and increased space within the room. The elegance of flush casements, with their clean lines and flat surfaces, adds a contemporary twist to the traditional bay window structure, making them a popular choice in both modern and period-style homes.

How can I get a quote for flush casement windows?

Obtaining quotes for flush casement windows is essential for finding the best balance of cost, quality, and service. Different double glazing companies offer varying prices and options, and quotes can help you understand the market rate, ensuring you make an informed decision that aligns with your budget and specific requirements for your home.

  • Research suppliers and installers: Look for window companies or local contractors in your area that offer flush casement windows. You can do this by searching online, checking local business directories, or asking for recommendations from friends or family
  • Contact multiple companies: Reach out to several companies to get a range of quotes, which allows you to compare prices and services. Many companies have contact forms on their websites, or you can call them directly, but the simplest way to gather multiple quotes at once is to use our quote form
  • Provide project details: Be ready to provide details about your project. This includes the number of windows you need, the dimensions of the windows (if known), the type of material you prefer and any additional features, such as double glazing, colour, or finishes
  • Ask about warranties and services: Enquire about warranties, after-sales services, and the timeframe for installation. Knowing these details can be as important as the cost itself
  • Review quotes: Once you receive the quotes, compare them not just on price, but also on the quality of the products offered, the reputation of the company, and the inclusiveness of the service, including installation, warranty, and aftercare

Frequently asked questions about flush casement windows

Flush casement windows, with their distinct aesthetic where the sash sits flush within the frame, often come with a higher initial cost than standard casement windows. However, this investment can be worthwhile for those valuing both form and function in their home design. 

These windows offer a sleek and contemporary look that enhances the visual appeal of a property, making them a popular choice for homeowners seeking to blend modern style with traditional charm. Beyond aesthetics, they provide benefits, such as improved energy efficiency, low maintenance, and the potential to increase property value. When these factors align with your priorities and budget, flush casement windows can be a sound choice, offering long-term value and satisfaction.

Flush casement windows typically incorporate multi-point locking systems, a significant security feature. This mechanism involves several locks at different points of the window frame, providing enhanced security compared to single-point locks. The multi-point system makes it more challenging for potential intruders to force the window open, thus adding an extra layer of safety.

With flush casements, the seamless design where the window sits in line with the frame minimises leverage opportunities, too. In traditional casement designs, how the window protrudes or the presence of more pronounced hardware can provide leverage points that skilled burglars might exploit to force the window open.

Adding secondary glazing can be more sustainable than replacing old windows, which can be wasteful and energy-intensive due to the manufacturing and disposal processes involved. It extends the life of existing windows, reducing waste and the demand for new materials.

While secondary glazing is environmentally beneficial regarding energy efficiency and sustainability, it’s important to consider the entire lifecycle of the materials used. For instance, the environmental impact of manufacturing and eventually disposing of the additional glass and frames should be weighed against the energy savings and reduced emissions. The long-term environmental benefits of improved insulation and reduced energy consumption often outweigh these initial impacts.

Windows cost calculator

See how much it would cost to get new windows for your home.

This calculator works using pricing data sourced directly from UK windows manufacturers. Prices are subject to fluctuations, however, so please use the results as a guide and contact suppliers for an exact price for your property.

Katharine Allison

Energy Saving Writer

As Independent Advisor’s energy saving expert, Katharine, a keen advocate for sustainability, is an authority on solar panels, double glazing, and cutting-edge renewable energy technologies. Her dedication merges with a commitment to enlighten and steer readers toward embracing eco-friendly solutions and the latest trends in sustainability.

With over 10 years of experience, she has worked with some of the UK’s leading companies and publications, including the Federation of Master Builders, Architectural Digest, and Denon Construction. 

Katharine is particularly passionate about consumer causes and animal welfare and has art, philosophy, and psychology degrees. She lives with her sled dogs in East Sussex.

Molly Dyson


After growing up with a passion for writing, Molly studied journalism and creative writing at university in her home country of the United States.

She has written for a variety of print and online publications, from small town newspapers to international magazines. Most of her 10-year career since relocating to the UK has been spent in business journalism, writing and editing for admin professionals at PA Life magazine and business travel managers at Business Travel News Europe and representing those titles at conferences around the world.

Now an Editor at the Independent Advisor, Molly is an expert in a broad range of consumer topics, that include solar panels and renewables, home improvements and home insurance, and consumer technology such as home security and VPNs.

In her free time, Molly can usually be found exploring the outdoors with her husband and their young son or gardening.