Window fenestration is critical to the appearance of your home. Get them right and they blend in like they were there from the day it was built. Get them wrong and it's a painful eyesore you'll either have to live with or pay to rectify.

Replacement windows should be considered as an investment in your home (likely your biggest single asset), so you need to feel assured it's a wise move. Doing your homework and gaining a thorough understanding of the products available to you is therefore an important first step.

We promise to provide you with as much information as possible about the choices you have and to discuss any aspect you may have concerns about. Some of the frequent questions are answered here.

Undoubtedly you’ll have read how we specialise in the very best designs, most authentic appearance, most advanced manufacturing techniques, the highest security levels and are leaders in energy efficiency.

Please don’t take our word for it! Ask us difficult questions, check out the statements we make and be sure to satisfy yourself with any aspect that concerns you no matter how trivial it may seem. Our products come with a whole host of endorsements that will make it easier for you to make up your mind... just ask!

These accreditations are over and above what's required to comply with current British and European manufacturing standards. We're members of these schemes because we wish to demonstrate the extra special quality you can expect when you decide to use a Bygone product for your home.

Click on the links below to find out more and just how you benefit from them.

British Board of Agrément


The (BBA) is the UK’s major authority offering approval and certification services to manufacturers and installers alike. They make sure...... 

we do as we claim, so you can rest assured knowing the windows have come through the most rigorous testing and that someone else is looking out for your interests, making sure we make quality sash windows. 

The BBA was set up on behalf of the Department for Communities and Local Government to provide independent testing. This validates claims made by manufacturers that their products conform to regulations and perform as expected. NHBC generally requires BBA certification for new buildings.

BBA Certificates have been providing authoritative and independent information on the performance of building products for over 35 years. Every Agrément Certificate contains important data on durability, installation and compliance with Building Regulations.

BBA Approval is recognised by building control, government departments, architects, local authorities, specifiers and industry insurers like the NHBC. Because our manufacturing facility is BBA certified, you can be confident that every window we make, meets the highest standard.

Complete approval, 20,000-cycle, “whole of life”, endurance testing

Our product range is fully BBA approved. That means we've asked that every component is tested, including the balances, even the unique hardware; additionally, and unlike any other company, our method of plant on Georgian bars also gets their approval for the next ten years.

20,000-cycle endurance testing is to simulate a “whole of life” test, it is an onerous test designed to recreate a 20-year lifetime of a product.


ISO 9001:2015


BBA certification tests confirm the products tested are durable, however companies must guarantee consistency of production and that they use the same products that satisfied the BBA testing.

A BBA certificate only confirms that the products tested, are durable, BBA tests themselves don't guarantee security or reliability, which is why we have ISO 9001:2015 in place too.

ISO 9001:2015 means our management system has reached the following standards:

  • an ability to consistently provide products to meet customer and relevant regulatory requirements
  • enhanced customer satisfaction through effective application of the system, including processes for the system’s continual improvement and conformity to customer and relevant regulatory requirements

But what sets us apart is the fact that we also have the BBA certification of quality, are Secured by Design approved, hold BFRC "A" rated certificates and are members of the GGF. We’re pretty sure you’ll find that makes us both unique and well qualified to make you great sash windows.

Rest assured, you are dealing with an established, well run family manufacturing business, one that's proud to uphold traditional values and who ensures the installers we recommend, also follow the same principals and who provide an excellent service.


Secured by Design


The Association of Chief Police Officers (ACPO) set up Secured by Design (SBD) to encourage the building industry to adopt crime prevention measures in housing. 

The scheme creates a safer and more secure environment, including safer windows.

Surprisingly, security isn't a British Standard! Yes products must be "fit for purpose" but that requires simply holding the window together, most standrad windows offer very little resistance to attempted break ins.

We pay to belong to this organisation and to have our products tested regularly. Very few products meet these enhanced security levels but fitting the same unique cam catches, finger latches and alike and having them independently tested by SBD, means you can be satisfied that your windows will be as secure as we claim them to be.

The programme is endorsed and supported by The Association of Chief Police Officers (ACPO) and funded through partnership with companies like ours. Our products meet technical standards identified by the ACPO – so the windows we supply you with are independently tested and deemed secure.

The scheme requires manufacturers to meet six core criteria:

1. Integrated approach – all interested parties are involved from discussions to completion of building developments.

2. Environmental quality and sense of ownership – ensuring the environment is well designed, attractive, well defined and maintained to promote a sense of pride, shared ownership and community responsibility.

3. Natural surveillance – designing the development layout to ensure community areas are open to view.

4. Access and footpath – adequate access that limits potential for multiple escape routes. 

5. Open space provision and management – making sure open spaces are overlooked and well maintained.

6. Lighting – ensuring communal areas and pathways are well lit and avoid shadow, for security and safety. 

Many companies will claim that their sash windows have SBD Accreditation when this is not the case, you can verify our claim by searching the SBD website – www.securedbydesign.com – selecting vertical sliding windows.




BFRC is the British Fenestration Ratings Council and they decide how to interpret energy efficiency calculations for the whole of the UK. All our windows are A rated as standard, but we can offer C rated which is still the industry standard requirement.

The BFRC rate products from F to A rating. A rated is energy neutral or energy positive, in that the window gains more heat than it loses over its annual cycle.




The Enery Savings Trust can only recommend the highest performing companies so only the best products that get to be Energy Savings Trust recommended. 

Having been awarded the first five certificates from the BFRC, (the British Fenestration Ratings Council), we were further recognised by the Energy Savings Trust as the first company to be recommended by them in the UK.

While building regulations require windows with a "C" energy rating or better, most of our bygone ranges come "A" rated as standard, however, those on a tight budget may prefer a compliant window of "C" rating.

One important consideration is that most companies remove steel reinforcement to maximise the energy performance of their windows, this weakens profiles considerably.

Bygone windows are different.

We've had ours tested with steel reinforcement (which drains heat) so that you get an "A" rated product which is energy efficient and a solid, secure sash window, recognised by the Police through their preferred standard, Secured by Design.


CE marking as standard


CE marking indicates that a product is compliant to EU laws so that it can be traded anywhere within the EU. 

‘CE’ marking is on many (but no all) products across the 27 member states of the EU together with Iceland, Turkey, Liechtenstein and Norway. 

The mark is proof that we, as the manufacture of sash windows is satisfied that the products we make meet the health, safety and environmental standards expected by Europe. Attaching the CE mark onto a product, signifies that as the manufacturer, we believe our products conform to these legal requirements, as set out by the EU.

Since july 1st, 2013 manufactures (those who place products onto the market) have had to mark their products. 


Made in the UK

We have always selected UK suppliers for our parts, components and machinery, however, following the referendum decision to leave the EU it is even more important that we continue this stance.

Our sash windows are manufactured at our factory in Essex.

Whilst we have a diverse range of cultures within the business, we are very proud of their contribution, skill set and attention to detail, it means that we can continue to make products using the very best quality from companies within the United Kingdom.

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These sash windows are only sold through our national network of premier partners, all of whom are certified and approved Bygone sash window installers




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What makes bygone sash windows so authentic?

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"We recently had 23 sash windows replaced"

"these windows are a premium range but secure, A rated and a very authentic grained appearance"

GP - Essex

Featured sash windows

  • Non Bar

  • Full Georgian

  • Half Georgian

  • Georgian Varient

  • Centre-Bar

  • Three Light

  • Marginal Border

  • Marginal or 'Off-Set'Three Light

  • Asymmetric

  • True Arch

  • Swept Head

  • Coupled Style 2

  • coupled Style 3

  • 1/3rd split

Sash window styles have changed in the last three hundred years but you can select whichever suits your home best.

Here are a few ideas >

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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