Bespoke sash windows in Forest Hill

Replacement sash windows and wooden sliding sash windows installed in Forest Hill, Sydenham and nearby areas

Installing Sash Windows In Forest Hill since 1980!

London Box Sash Windows is your go-to local expert for sash and replacement sash windows. We specialise in crafting bespoke sash windows using premium Accoya wood and A-rated double glazing. Our sash windows blend traditional elegance with modern energy efficiency and long-lasting durability.

Accoya wood, known for its sustainability and resistance to rot, decay, and warping, is the ideal material for sash windows. Combined with high-performance double glazing, our box sash windows offer outstanding insulation, helping to lower energy bills while maintaining timeless charm.

Our sash window team is highly rated on Google reviews and has received top feedback on Which? Trusted Traders, where we have been members since 2011.

One recent customer said:

Very efficient local team, first to book appointment and good contact from Judith in the office. Very thorough presentation from Jake and ability to offer a discount for speedy installation. Andy installed windows and he was professional & friendly. A very clean and methodical approach. They also have an after service care should anything happen which is very reassuring .I have already recommended them to two friends of mine.

All our sash window products are made locally at our London factory near Wimbledon, with 90 per cent of installations within eight miles of production, supporting the community and reducing our environmental impact.

Visit our showroom to explore our sash windows and get expert advice from our knowledgeable team to find the perfect match for your home.

What makes our Sydenham sash window company different?

At London Box Sash, we are passionate about preserving the timeless beauty of sash windows while enhancing your home with modern products. Our skilled team focuses on using the highest quality materials and providing flawless sliding sash window installations that respect the traditional aesthetics of your property. This dedication to craftsmanship and attention to detail has made our services highly sought after and widely recommended.

John Ellis founded our first workshop in 1980, and since then, we have proudly specialised in crafting double-glazed sash windows and doors designed for lasting durability.

With a commitment to traditional craftsmanship and modern innovation, we have grown steadily over the decades. By continually investing in state-of-the-art machinery and refining our techniques, we ensure that every product we create meets the highest quality standards, blending timeless aesthetics with superior performance for homes across the region.

We take the time to explain the intricacies of sash windows, from their history to their functional benefits, ensuring you are fully informed at every step. Whether you are restoring an older property or adding character to a new build, our team is committed to helping your home find its perfect style.

Another client said:

I was very happy with the bespoke casement window they installed in my property. The company also agreed to repair it promptly after a number of years. London box sash install high quality timber windows and seem to care about their customers.

For images of our recent sash window installation projects, please check out our portfolio.

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We fit Accoya sash windows and wooden sash windows in Forest Hill, SE23

Forest Hill in South-East London is known for its charming, tree-lined streets and beautifully preserved period properties, many of which feature classic sash windows integral to their architectural character.

From Georgian townhouses to Victorian terraces, these homes reflect a timeless elegance that makes Forest Hill a sought-after area for homeowners. However, due to the age of many of these properties, original sash windows may have become worn or inefficient over time, leading to drafts, condensation, or difficulty in operation. R

Replacing sash windows with high-quality, energy-efficient replicas can enhance the comfort and aesthetic appeal of these heritage homes. Accoya wood undergoes an innovative acetylation process, making it exceptionally durable and resistant to decay, rot, and insects. This increased lifespan is complemented by its remarkable dimensional stability, ensuring smooth operation and a longer life.

Accoya’s low maintenance is a key benefit, as its reduced water absorption extends the life of finishes. Its thermal insulation properties improve energy efficiency, making it an eco-friendly option that can lower energy costs. Accoya wood also supports sustainability, offering both the environmental advantages of softwoods and the durability of hardwoods, earning C2C Gold certification.

Forest Hill A+ rated sliding sash window installation

Double-glazed sash windows can significantly enhance your home’s energy efficiency. According to the Energy Saving Trust, installing A-rated double-glazed windows in a single-glazed semi-detached home can save homeowners around £195 per year.

The insulated air space between the glass panes in double or triple glazing helps reduce heat transfer by slowing down convection and conduction, keeping your home warmer for longer and lowering heating costs, making it a smart investment for energy-conscious homeowners.

Please see our blog: How long do double glazed windows last?

gervase

We recently had our sash windows installed by London Box Sash Windows, and the whole experience was excellent.

Anjelo and Raf, the installation team were respectful, professional, and did a wonderful job. Jake who looked after us on the sales side, was helpful and knowledgeable, Judith kept it all organised.

The sash windows themselves look absolutely beautiful and have completely transformed the appearance of the house. We’ve had a number of compliments from people passing by, which speaks for itself.

Brad V

You do not need to worry because this company make, supply and fit the best windows around.
I have used them well over 10 years on various projects and i would not go elsewhere. What can i say other than ‘superb in every respect’
Their choice of wood and paint is astonishing as they never move or crack and look like they were fitted only yesterday even though my original windows from them are well over 10 years old, i have never had to do anything to them.
I cannot express how brilliant their products are and, their service is fantastic. I would never use any other supplier.

Phil Bowen

We have used London Box Sash Windows twice in the past four years. We can’t speak highly enough of the customer service, the ease of the sales process, the quality of the work and the professionalism of the window fitter. We now have a beautiful set of windows in our house and would not hesitate to recommend them.

Helen Jenkins

I found London Box through Which Trusted Traders and was so glad that we chose them to replace a bathroom window in 2025 following it being damaged through an attempted break-in. We were so impressed with the service given by the company through the assessment visit by Simon, the contact and support through the office of the lovely Judith and the amazing work done in a single day by the wonderful Andy to replace the window. He worked tirelessly all day and cleaned and tidied up beautifully afterwards. Because of their impressive service installing this window we employed them to replace the bay windows on our house which was a much bigger and more complicated job because of issues to do with the state of the bay itself but London Box were more than up to it. This time Harry came to measure up and Judith in the office continued to keep us informed and up to date with the process. Angelo and Raf did a fantastic job on the day installing the new windows. It was a very difficult job but they did amazingly well and we couldn’t be happier with the windows as well as with every aspect of our involvement with the company. Would throughly recommend this company and not hesitate to use them again in future.

Andrea Melville

I have used London box sash windows three times. The product stands the test of time. We had upstairs bedroom windows installed in 2014. Lounge in 2021 and bathrooms 2026. They open as easily today as when installed. Service is professional. Everything left clean. When some water got in some glass it was replaced quickly with no fuss. A great experience and a great product.

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Excellent result from these guys- they are extremely efficient, turned up on time, did a great job with an old rotten window, cleaned up afterwards and were polite and friendly

Pete Stoneman

After getting quotes from three sash window companies, we chose London Box Sash to replace six old, single glazed sash windows. Every step of the process was great and the new windows have massively improved the look of the house from the street – as well as making it better insulated for noise and warmth.

At the initial home visit Jake clearly explained the different options available to us and their respective costs. I didn’t feel rushed or pressured with an upsell. Harry took measurements at the pre-manufacture survey, confirmed our chosen options and explained the installation process.

We were also invited to visit the factory, and it was great to see the windows being made locally.

Andy, the window installer, was absolutely fantastic. He arrived on time every day, was a hard worker, and showed real attention to detail. He also took the time to explain what he was doing at each stage of the install.

I would not hesitate to recommend London Box Sash to others and will reach out to them when we need other windows replacing.

Dominic Elliott

I had all of our front windows replaced with London Boxsash wooden sash windows and couldn’t be more delighted.

The window demonstration was really informative and I could tell from the start that the windows were far superior to any others I’d seen.

The booking process was very smooth and the installation team were by far the most professional, fast and tidy I’ve ever witnessed.

This isn’t a cheap product but represents superb value for money.

Book a sash window survey in any of the nearby locations:-

Beckenham
Catford
Dulwich
Forest Hill
Honor Oak Park
Lewisham
Norwood

Would you like a quote for sash windows or casement window installation Forest Hill? Call London Box Sash now

For an estimate for casement windows or replacement sash windows near you, please call [telme] or email [emailme].

Call our team for sash windows Putney.