Up to 5% discount on all products. Extra: Free upgrade of Insulation to All cladding orders.

Casement Window Installers In Essex

Casement Windows By Greenoaks

At Greenoak Concept & Design, we believe in offering the best possible windows for your home, and that includes our top-of-the-line casement windows. Casement windows are hinged on the side and open outward using a crank or handle. This design allows for excellent ventilation and unobstructed views when open. We use Deceuninck’s industry-leading window extrusions, crafted from 100% lead-free PVCu. Their innovative chamber systems provide superior insulation, strength, and acoustics, while the bubble gasket creates an enhanced weather seal. This means you’ll enjoy a quieter, more comfortable home with less energy wasted.

Market-Leading Energy Efficiency

With the introduction of our new casement windows, we are offering superior energy efficiency, market-leading U-values and a drive towards sustainability.

As the Future homes standard are introduced, the energy efficiency of a home and U-Values for windows will become more important. Greenoak Concept & design Double Glazed and Triple glazed Casement windows have an ultra-low U-value. Our deceunick frames are made with recycled uPVC and the window can be recycled at the end of life to reduce the impact on the environment.

Greenoak Concept & Design

Casement Window Gallery

Choose the perfect finish from our wide array of combinations

We understand that your windows should complement your unique style, which is why we offer a wide range of colour options and combinations for your Greenoak casement windows. From classic neutrals to bold modern tones, with the option for a different colour on the interior and exterior, there’s a perfect combination to suit any space in your home.

Casement Window Furniture

While Greenoak Concept & Design excels in window performance, we understand the importance of aesthetics too. That’s why we offer a wide variety of window handle styles and colours to perfectly complement your home’s design. Our handles are built for flawless operation and outstanding quality, ensuring a smooth and long-lasting experience. Plus, we’ve recently expanded our range to include premium anti-corrosion designs, rigorously tested to withstand even the harshest weather conditions.

Frequently Asked

If you have any questions in relation to our casement windows, then look no further. This FAQ section answers some of the most common questions we come across. If what you had in mind is not mentioned here, please don’t hesitate to contact us and we will be happy to answer any question you may have.

Side-Hung: The most popular type, these windows boast hinges on one side and open outwards.
Single Casement: This basic style features a single frame, typically side-hung for classic functionality.
Double Casement (French Casement): Featuring two side-hung frames with central mullions, these windows open outwards on both sides for a wider opening.
Awning Window: Hinged at the top, awning windows swing outwards from the bottom, ideal for deflecting rain.
Hopper Window: Hinged at the bottom, these windows open inwards at the top, offering ventilation and security for upper floors.

Greenoak Concept & Design uses Deceuninck’s industry-leading window extrusions, specifically designed for exceptional thermal performance. The chamber systems and 100% lead-free PVCu construction provide excellent insulation, reducing heat loss in winter and heat gain in summer. This translates to lower energy bills and a more comfortable living environment.

Window Frame – holds the casement window in place.

Window Sill (or cill) – forms the bottom of the window frame and directs water away from the frame.

Casement – is the part of the window that opens, securing the glazing in place.

Mullion – is the vertical strip that divides separate window units.

Transom – is the horizontal strip that divides separate window units.

Lock Handle – the window’s locking mechanism is located on the casement jamb.

Trickle Vent – at the top of the window, trickle vents consist of a grill on the outside and a closing vent on the inside.

The flush casement window offers a sleek upgrade to the traditional casement. Unlike standard designs that protrude from the frame, the flush casement sits seamlessly within it. This creates a modern aesthetic and boasts improved weatherproofing and draft resistance. Combined with a slim aluminium frame, it’s the perfect choice for a contemporary look.

Casement windows shine with their versatility. From classic styles to contemporary looks, their material options make them suitable for any property.

However, it’s important to note their size limitation. The weight of the glass panel dictates the maximum size a single hinge can support. This is why casement windows often come with various sized panels in a single frame.

Security is a top priority at Greenoak Concept & Design. Our casement windows are built with high-quality materials and incorporate robust locking mechanisms to deter potential intruders. Additionally, the casement design itself makes it more difficult to force entry compared to sliding windows.
Greenoak casement windows are designed for low maintenance. The smooth PVCu surface is easy to wipe clean with a damp cloth and mild detergent. The advanced bubble gasket technology also helps to minimise dust and debris build-up, reducing the frequency of cleaning required. For optimal performance, we recommend a periodic inspection of the hinges and locking mechanisms to ensure smooth operation.

We are confident in the quality and durability of our Greenoak casement windows. That’s why we offer a comprehensive warranty on both the Deceuninck profiles and the manufacturing process. The exact terms of the warranty will vary depending on the specific product, so don’t hesitate to contact our team for detailed information.

Casement windows are generally considered a cost-effective option, with white uPVC being the most affordable choice. Prices typically range from £600 to £2,000 per window, depending on size, glazing design, and the number of windows replaced at once. While the average cost for new windows falls between £600 and £3,600 per window, remember, the final price depends on your specific customisations.

The world of window glass extends far beyond a basic pane! Here’s a breakdown of popular options to help you pick the best fit for your needs:

Low-E Glass: This “all-rounder” delivers impressive energy efficiency, making it a popular choice.
Low-Iron Glass: Offering superior clarity and maintaining energy efficiency, this glass allows for a more natural view.
Toughened Glass: Boasting five times the strength of standard glass, it prioritises safety.
Laminated Glass: Featuring a plastic interlayer, this glass enhances insulation and provides increased resistance to damage.

We're trusted within our industry
Learn more about us

Based on 56 Reviews

Good original consultation with Dale, general advice without being pushy. Survey efficient and quote broken down and understandable. Very good team from Greenoak, work done as per schedule, clean and tidy. Very considerate when one of us was unwell, kept the noise down. Problem with garage door investigated and rectified very quickly. Really pleased with final result, completely transformed external appearance of house. Thanks to whole team inc Tom Jay Mike Dave Callum Ed and esp Mark and Tegan.

Kitty Heyns

Amazing service from start to finish. Wouldn't go anywhere else, highly recommend to anyone.

Danny Clark

5 * very helpful and professional great service 👍 👏 👌 highly recommended.

Roman Clark

This my second time using Greenoaks Conecept and design , I cannot vouch for them enough ! Dale and the team completed a very a high standard of work throughout on a few properties for me and would highly recommend to anyone looking .


Dale and his team are amazing! I will use them again!

Mary Dean

Highly recommend this company. Had our conservatory roof done and they did a fantastic job. They kept us informed every step of the way of what would be happening. Cleaned up at the end of each day and was very hardworking, polite and friendly.

Dale has been a star. From his first visit to give me a price, to completion of the works. Punctuality and communication of the Greenoak team (Dave/Ray/Callum) was excellent.I am so pleased with the job that Green Oak have completed for me. They were professional, tidy and worked so hard. The job is finished to a high standard and I will 100% use them again. Would highly recommend.

Maria Howe

Job was done in the hours I was told. Very efficient and happy with my new conservatory roof. Thank you and would happily recommend Greenoak

alan shinn

We recently had relacement windows and doors by Greenoak Concept. Many thanks to Dale and all the team,they are very professional, punctual, polite and leave the job in a clean and tidy condition. Very pleased with the outcome, many thanks to all at Greenoak.

Dale and the Greenoak team are fantastic; having delivered 2 large projects on our house, both on-time and on-budget (and with a laugh & smile!) we can’t recommend them enough! Thank you!

Professional job.

Nick Brennan

So far very happy with the installation . Our tired old conservatory has been totally transformed by the team at Greenoaks. They worked cleanly and efficiently whilst navigating our day today running if the house. We’re actually looking forward to the heat of summer and cold of winter!!

Dale, you and your team, thank you so much for your time and dedication. Our new composite Rock door looks and feels fantastic. It feels really good using a local company that cares about their customer from start to finish. Thank you

We have had a solid roof put on our conservatory by Green Oak. We were very impressed from the outset. Dale took time to explain every aspect of the build bringing a model of the roof so we could see the construction. Then he left us think about it and there was no hard sell. The workmen were very pleasant, friendly and worked extremely hard. Despite being one man down the other chap worked late into the evening to make sure the construction was finished on time ( rather than have to come back for a couple of hours the following day), as did the man doing the plaster boarding. Every evening the site was left tidy and all rubbish taken away once the work was finished. The plasterer and electrician also did a brilliant job and all works was finished on time. We are really happy with the end result and couldn’t recommend the firm more highly. John & Rita Dobinson

Nicky Boosey

Dale was very professional in giving us sound advice and explained the whole process from start to finish. The job commenced on time, Mike and Mark treated our home with respect and were very knowledgeable and kept us informed all the way along. The quality of work is excellent and we would recommend them.

Ian Creek

We needed 11 new windows of various sizes so we spent some time searching reviews for a highly rated but local Double Glazing window installer. Greenoak came out top of our search results, We reached out and Dale responded quickly followed by a visit a few days after. The resultant quote was very competitive versus other quotes we had received. It was an easy decision to go with Greenoak. Dale came across as very knowledgeable, friendly and genuinely customer focussed. He invited us to the showroom in Leigh where he took us through the detail to ensure we were fully aligned on requirements and expectations. We were very impressed with him and his business and by his overall professionalism. The installation took place on 20th Feb 2023 and took 4 days in total. The whole process was exemplary, we could not fault the team in any way. They were tidy, considerate and very thorough. We have had windows fitted before by various other company's but the quality of fit and finish from the Greenoak fitters was far superior. The guys worked solidly and clearly did not skimp on anything, ensuring that the windows were not only properly fitted but sealed professionally too. They did an outstanding job including clearing all of the old windows and rubbish Overall we'd rate Greenoak at 10/10. We felt reassured by their high standards of work ethics, integrity and customer satisfaction. We honestly doubt there is anyone better out there for this type of work. We therefore wholeheartedly recommend them Ian and Jenny

Fantastic job done by Greenoak, the guys were professional, friendly and a pleasure to have in my home. I couldn’t be happier with the job they did. Highly recommended.

Brilliant company, very friendly and easy to work with. Very pleased with the finished cladding on our office wall - excellent quality and good value


Replacement Conservatory Roof. Fantastic company and service from the whole team! Dale is great and gave me a quote for my new lightweight roof, great bloke and not pushy, loved the fact he gave a all in price rather than start low and add extras. The fitting team are fantastic!, Mike, Mark and Casper treated my home like their own, , great attention to detail and did everything I asked to get the perfect finish, I honestly cant find 1 fault and I am fussy! I could not be more happier with my roof!! Take my advice, Don't look anywhere else ,I cant rate them highly enough. Greenoak are the BEST!

Following our initial discussions with Dale, our expectations were already set high when it came around to installation. Some truly awful weather right at the start of the installation virtually wiped out the first two days work, and the anticipated seven day build seemed to be in jeopardy right from the start. But Mike and his crew - supplemented by two and sometimes three others, working in still inclement weather, brought the build back on schedule by the end of day five, and the plastering and electrical second fix over days six and seven meant the whole project was delivered to time, and budget meaning that our initial high expectations had even been exceeded. I have nothing but the highest regard for their workmanship and scheduling - and not forgetting Dione in the office who kept me informed throughout and efficiently managed the stage payments. In my experience it is unusual to receive a great sales pitch and then to have that exceeded by the installation teams - I couldn't recommend Greenoak's services more highly.

Our team are
ready and waiting
to help you...

Greenoak Concept & Design have been raising the standards for more than 10 years.

More about us: We’re an independent Essex-based specialists in high quality UPVC Windows, Doors, Tiled Conservatory Roofing, Wall Cladding, and Fascias, Soffits and Guttering.


Free Quotation