All Bygone Harmony sash windows will have a white, wood alternative, acrylic finish. Grained and textured to the touch, this UV stable foil, protects the base material and your windows from sunlight. The outer frame will have a traditional "staff bead" design and the sashes will feature a chamfered leading edge, to recreate the traditional, "putty glazed" appearance.

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



Every deep bottom rail and run through horn on Bygone Harmony sash windows have traditional vertical joints which, with the grained, textured, acrylic wood foil, produces the perfect, authentic sash window appearance. When most people are first introduced to this finish, they can not believe it's not wood.

While we will happily consider any request for special glass designs, patterns or sound reducing glass units, Bygone Harmony 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 sealed 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 Harmony 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. Unique and again patented, when we fit two cams, they're a matching pair of left and right hand. These centralise large sashes 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.

Harmony has a choice of Acorn or Beehive designs of furniture if you prefer the Porcelain ball design is available on Harmony windows, as an optional extra. 



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 Harmony 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. Our premier partner will be pleased to discuss the precise location before fitting them.

All bygone furniture is branded so you know you are getting bygone windows and colour suited. Colours include Antique Brass, Pewter or polished Chrome. Other colours may be available upon request. 



All sliding windows have TORSO balances. The "Rolls Royce" of spring balances, pretensioned by the balance manufacturer they're tailor made for each window we produce. These are made to the precise length and weight of your windows, ensuring sashes are perfectly counterbalanced.

All sliding windows have "sash secure" finger latches, 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 and accessibility 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 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 if two stage keeps could be used as an alternative, as they are far more attractive and functional, 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 buyers guide, by following the links.


Manufacturing standards

Bygone Harmony sash windows are manufactured in a state of the art factory to exacting standards, to your bespoke requirements. Independent, third party vetted 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.


Organic where possible.

Our composite materials use, Acrylic, Steel, PVCu and Fibre glass (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 replaced by organic ones, and about half of our PVCu material is salt – a natural substance.

As materials are recycled, so PVCu, steel and glass time and time again, meaning they should avoid landfill altogether.


More Information

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 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

Download now >

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

Request a Quotation

Would you like to see a sample, discuss your requirements and options, or obtain an assessment of the costs for your project?


If you would like a copy of our brochure please click the download button at the bottom of this page.