All Bygone Symphony sash windows have a white, wood alternative, acrylic finish that is grained and textured to the touch. This UV stable foil protects the base material of your windows from sunlight. The outer-frame has a traditional "staff bead" design and the sashes feature a chamfered leading edge re-creating a traditional "putty glazed" appearance.

A slim 50mm profile is used for the upper sash, and a larger 63mm profile for the lower sash. This ensures the glass widths are identical visually, which means any Georgian bar layout is balanced between the upper and lower sashes. The standard Symphony specification incorporates a traditional 105mm (4") deep bottom rail, but again the glass heights is equalised so that Georgian bar layouts are balanced within the window, replicating the good craftsmanship of earlier centuries.  



The Bygone Symphony introduces an industry first for PVC-U sash by introducing a 'Super-Slim' mid-rail measuring an astounding 39mm. Whilst only being a difference of 13mm, the aesthetic difference is striking, making the Symphony almost indistinguishable from its timber counterpart. We have even replaced the internal 62mm meeting rail for a much slimmer 52mm. This allows us to reduce the amount of profile on show, but still gives us enough space to reinforce the section and secure our furniture in line SBD expectations.



Every corner on Bygone Symphony sash windows, have traditional vertical joints which, with the grained & textured acrylic wood foil, produce the perfect, authentic sash window appearance. When most people are first introduced to this finish their first reaction is that it's wood.

While we will happily consider any request for special glass designs, patterns or sound reducing glass units, Bygone Symphony sash windows have slender, 18mm (4/10/4mm) Krypton gas filled units, to allow our exclusive deep Georgian bar and glazing bead. Unique interlocking bars form a grille which is firmly attached to the glass surface, while the bar ends are clamped in place using patented, stainless steel "Georgi-clips" which wrap around the end of the sealed glass unit.

Externally chamfered sashes and bars provide the traditional, "putty-glazed" appearance and are secured in the same fashion.

Manufactured to EN1279, all sealed units carry a five-year guarantee. The glazing consists of 4mm Low Iron: 16mm Argon gas, Thermix spacer bars: 4mm Soft coat Low E en.040.



One feature that has been a tell-tale indicator of a PVC-U sash window is the width of the mullion between double and single windows. Traditionally they have simply been two or three single windows, coupled together on one cill section. The new Bygone slim mullion puts the width of this section at almost the same narrow profile of timber and with its own ‘staff bead’ timber effect profile it blends beautifully with the frame bead of the windows. Double or triple PVC-U sash windows no longer look bulky or ill proportioned and will complement the period aesthetics of your home.



All Symphony sash windows over 926mm will have two cam catches automatically, however bar layouts will on occasion require us to fit two cams on smaller windows. When we fit two cams, they're a matching pair of left and right handed locks, another unique and patented feature of Bygone. These centralise large sashes more securely within the frame for better security.

These cams and keeps are solid materials. While the cam base and keeps are cast alloy, the claw itself is solid stainless steel, which together with the seven fixing screws ensure Bygone cams and keeps won't be forced apart. Each keep is also fitted with a special nylon insert to protect the plated surface of the stainless steel claw.

Symphony has it's own special Porcelain ball designed cam and finger latches, although we'll fit the Acorn or Beehive furniture if you prefer... just ask! 



Again, unlike clumsy surface mounted devices which are fiddly to use, all Bygone sash windows have a pair of recessed limit stops which are silky smooth and do not protrude from the surface of the sash until open. All Symphony windows have two, flush fitting recessed limit stops (one either side) in the upper sash, unless they're not required. 

Two scroll handles for the lower sash along with a ring pull for the upper sash are supplied with each sash window. Any of our installers will be pleased to discuss the precise location before fitting them.

All bygone furniture is colour suited but also branded so you know you are getting an exclusive bygone window. Colours include Antique Brass, Pewter or polished Chrome. Other colours such as Black or Satin Chrome may be available upon request. 



All sliding windows have TORSO balances otherwise known as the "Rolls Royce" of spring balances. These are pre-tensioned by the balance manufacturer and they're individually tailor-made for each window we produce. Manufactured to the precise length and weight of your windows, they ensure the sashes are perfectly counterbalanced.

All sliding windows have "sash secure" finger latches which are steel reinforced and wrapped around each corner. They centralise sashes within the frame and provide extra resistance against forced entry.

All tilting windows are fitted with a pair of 'tilt arms' (one either side of the sash) to allow the safe lowering of the sash and extra access for cleaning the outside surfaces. Where sashes are too large or heavy for the tilt facility, they will be fitted with "safety stays", a small restrictor which prevents the accidental release of very heavy units.

All cill joints have our unique cill pads proven to prevent water ingress, balance retaining clips to secure balances to the frame mounted shoes for the life of the window, and foam draught baffles to improve performance to its maximum.

Whilst trickle vents can be supplied we'd recommend you consider how two stage keeps could be used as an alternative as they are far more attractive and arguably more functional, as only providing trickle ventilation when you require it. Please note that where two stage keeps are fitted for ventilation purposes, the window will not be PAS24/Secured by Design accredited when locked in the secondary position.

Please check the glossary of terms if you are unclear about any of the above terminology, you can download a brochure, technical details or a by following the links.



Bygone Symphony sash windows are manufactured in a state of the art factory to very exacting standards. Each window will be meticulously designed and manufactured to your bespoke requirements. Independent third-party vetting of our factory and production methods by the British Board of Agrément (BBA) guarantee our claims of product endurance and longevity. They've been tested to 20,000 opening cycles which simulate 20 years opening and closing on the COMPLETE window including balances, hardware and plant-on Georgian bars.


Our composite materials use, Acrylic, Steel, PVC-U and Fibreglass (or GRP). We recycle our post-production waste and use natural materials whenever possible. Fossil-based oils are replaced by organic oils, lead-based stabilisers are replaced by organic ones, and about half of our PVC-U material is salt, a natural substance.

As most household materials are recycled, so are PVC-U, steel and glass. We recycle time and time again, meaning these materials should avoid land-fill altogether.



If you like you can view a copy of the brochure and download it here, if you prefer we'll send you a hard copy in the post. If you're ready to know more, would you like to see a sample, discuss your options in detail or obtain a free assessment for the costs for your project, then please complete the enquiry form with your contact details.

You can find an approved local premier partner here, who'll happily explain your choices and provide a no-obligation, fully detailed, written proposal.

If you prefer some answers now, please type your question into the chat box on the right hand side of the page or simply call our free phone number, we'll happily help you resolve your sash window problems.


Further information:

Buyers guide

Take a look at the bygone byuers guide

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Product manual

see the full bygone collection manual

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Technical details

Download the bygone technical details

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Accreditations >

Learn why you get better windows because of these

  • BBA - British Board of Agrément Certified
  • ISO 9001:2015 Certified Organisation
  • SBD - Secured By Design Approved Windows
  • British Fenestration Ratings Council - A Rating
  • Energy Savings Trust Recommended Windows
  • CE Compliant Windows
  • All Bygone windows are manufactured in the UK

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