Double Glazed Sash Windows
From sustainably sourced timber to low-maintenance uPVC, every one of our sash windows is made to order with double glazing and installed by our FENSA-registered team. With FSC-certified materials and a GGFI-backed 10-year guarantee, you can count on lasting performance, authentic detailing, and total peace of mind.
Our Range
Crafted from FSC-certified hardwood or softwood, our timber sash windows are built to last and finished to the highest standards.
Choose between cords & weights or spiral balance mechanisms – both delivering smooth operation while preserving the character of traditional joinery.
Every timber sash is double glazed as standard and can be further upgraded with acoustic or slimline glass for added performance.
Designed specifically for conservation areas and listed buildings, our Heritage timber sash windows feature run-through horns, lamb’s tongue mouldings, putty-bead bars, and slim frame sections.
Available with ultra-slim 14mm double glazing or 8mm vacuum glass, they maintain the look of single glazing while delivering modern performance.
Our team can assist with planning applications to ensure a smooth and compliant installation.
For homeowners seeking a more cost-effective and low-maintenance solution, our uPVC sash windows deliver excellent performance in a traditional style.
Choose from contemporary, traditional, and heritage designs – all A-rated for energy efficiency, with tilt-in sashes for easy cleaning and secure locking systems for added peace of mind.
A true architectural classic, box sash windows are synonymous with Georgian, Victorian, and Edwardian design.
We offer beautifully detailed box sashes in both timber and uPVC, with options for traditional cords & weights or modern spiral balance operation.
Every unit is double glazed and made to mimic the original profiles, including deep bottom rails, horn details, and period-accurate sightlines.
How Our Double Glazing Works
- Each unit features Low-E glass with a near-invisible metal oxide coating that reflects heat back into your home.
- Between the panes, argon gas is used to reduce heat transfer and boost insulation.
- Warm edge spacers help eliminate cold spots by reducing thermal bridging at the edges of the glass.
- With U-values as low as 1.2W/m²K, double glazed sash windows significantly improve thermal insulation, helping to lower your energy bills and boost your EPC rating.
- Whether you opt for sustainably sourced timber or low-maintenance uPVC, every window is made to replicate original period detailing while delivering long-term durability, security, and ease of use.
- Acoustic glazing options make them ideal for cutting out urban noise – perfect for homes in busy areas.
Heritage & Conservation Expertise
With more than two decades of experience working on London’s period homes, we understand the sensitivity required when upgrading windows in listed buildings and conservation areas.
Our Heritage timber sash range features slimline and vacuum glazing options designed to meet planning guidelines. We replicate original joinery in exacting detail, from mouldings and horns to putty bead finishes, and offer full support with planning applications.
If you’re looking to improve comfort while preserving architectural integrity, we’re the specialists to trust.
Secondary Glazing for Heritage Homes
If you’re unable to replace your original windows, secondary glazing offers an effective, discreet alternative.
Fitted to the inside of your existing frames, it delivers up to 70% noise reduction and dramatically improves thermal performance – without changing the exterior appearance of your property.
Ideal for listed buildings and conservation areas, secondary glazing requires no planning permission and can be made to match your current sightlines.
10-year warranty on upvc windows
10-year warranty on glazing
5-year warranty on ironmongery & seals
Expert Installation & Aftercare
From first visit to final sign-off, every installation is handled with care and professionalism.
- Our FENSA-registered fitters follow a step-by-step process to ensure a smooth installation with minimal disruption.
- We protect all floors and furnishings, clean up thoroughly, and offer timber care packs to help you maintain your windows for years to come.
- Every project is backed by a GGFI 10-year insurance-backed guarantee, giving you complete peace of mind long after we’ve left your property.
Full Protection on All Double Glazed Sash Windows
Our double glazed sash windows are backed up with industry-leading guarantees across every component. You’ll receive:
- 30 years on timber material (covering rot, fungal decay, and warping)
- 10 years on paint finishes for timber frames
- 10 years on glazing and installation workmanship (timber & uPVC)
- 5 years on ironmongery and weather seals
These guarantees come as standard from day one, at no extra cost.
How Much Do Double Glazed Sash Windows Cost?
Because every window is made to order, pricing depends on size, style, and material– timber typically costs more than uPVC. To give you an accurate quote, we offer free site surveys with no obligation. Our team will assess your property, talk through your options, and provide clear pricing for your project.
Invest In Double Glazed Sash Windows
Whether you’re restoring a period property or upgrading your home’s efficiency, we’re here to help.
Get vintage looks and modern energy performance, saving you money on heating bills and keeping you warm through the winter.
Explore our brochure to learn more about our fantastic range and service, or speak to a member of our team about your needs to get started.
FAQs
What’s the difference between uPVC and timber sash windows?
Timber sash windows are ideal for period properties and conservation projects. uPVC sash windows are more cost-effective, low maintenance, and still replicate traditional aesthetics well – particularly our Heritage range.
Do you offer triple glazing or acoustic glass?
Yes. Both timber and uPVC ranges can be upgraded with triple glazing or acoustic glass to reduce noise in busy areas. We also offer secondary glazing as an alternative for properties where replacement isn’t possible.
How long does installation take?
A sliding sash is a window with two pieces, or sashes, that slide up and down to open and Most installations are completed in 1–2 days per room, depending on access and window quantity. Our team will give you a clear timeline and protect all working areas to minimise disruption.
Can I visit your showroom?
Yes. We have showrooms in Clapham and Surbiton where you can view our full range, speak to our team, and finalise your design choices. Book your visit.
Do you offer planning support?
We do. For listed buildings and sensitive areas, we can help prepare and submit planning applications as part of our heritage sash window service.
What is vacuum glazing?
Vacuum glazing uses two panes of glass with a tiny vacuum between them – offering thermal performance that exceeds triple glazing, with the ultra-slim appearance of single glazing. It’s ideal for listed properties where traditional looks must be maintained.