When purchasing doors and windows for a new build or as replacements, it’s crucial to understand the significance of door and window double glazing guarantees and warranties. Double glazing guarantees can protect customers from defects in materials and poor installations.
During your research, you’ll encounter numerous door and window professional bodies and trade associations highlighted as a ‘badge’ on the company’s marketing materials; knowledge of these will help homeowners protect their investments and make informed decisions.
This article is a valuable resource for homeowners to navigate the ‘badges’ as it delves into the purpose of double glazing guarantees and helps identify which double glazing guarantees are meaningful for your project.
What you need to know about double glazing guarantees
Double glazing guarantees can come in the form of memberships of trade associations and professional or ombudsman bodies, which we will call ‘schemes’ going forward in this article. Installation companies join these schemes to demonstrate to the consumer that they are one way of minimising the risk of bad advice or installation, promoting their professional standards, and proving their credentials.
As far as the consumer goes, this can only be a good thing. Otherwise, there will be no way of benchmarking and comparing one company to another. However, you need to know what all these schemes are, what joining entails and what backup you will get if something goes wrong. Otherwise, the double glazing guarantees are worthless.
The most likely problems that a consumer could face are:
- Lost deposits: companies disappear or go into administration before delivery and installation
- Incomplete installations: Work started, but getting them to return to finish is proving difficult
- Disputes over quality of work: From minor snagging to botched jobs
- Glass failure: Cracked or scratched on installation, failure of the double glazing panel with condensation between the glass
- Product failure: Such as doors not closing, warping of the frame, and bi-folding doors misaligned
- Hardware failure: Such as locks and hinges.
With this list of possible issues, we move into two different areas: guarantees and warranties.
What is the difference between double glazing guarantees and warranties?
The terms “guarantee” and “warranty” are often used interchangeably, but they do have a point of difference:
A guarantee often refers to an assurance or general promise that the product will meet certain standards or perform as expected and not about defects like warranties. Guarantees are not enforceable; they could be legally binding if documented in writing.
A guarantee is a promise to repair or replace, as per the guarantee’s terms and conditions, should a problem develop within a specified period and for specified components. The length and scope of the guarantee can vary depending on the manufacturer, the materials used, and the parts covered. Guarantees start from 5 years and can be for a lifetime – all guarantees could be worthless unless backed up with an insurance-backed door guarantee.
A warranty provides the buyer with some legal rights for a fixed term, such as compensation or repair or replacement of a defective part or product that does not meet the stated standards. The warranty will have terms and conditions that specify what is covered (as well as what is not covered) and for how long.
To sum up, a warranty is usually provided by the designer and manufacturer of the door or window. The installation company usually provides a guarantee and should pass on the warranty details to you from the manufacturer.
For this article, we will include a ‘warranty’ in the schemes list.
A guide to double glazing guarantees schemes
There are many double glazing guarantees through trade associations and professional and ombudsman bodies, both private and Government-backed.
For some schemes, members pay annual fees, whereas others are free, and others charge only for the required service, such as insurance policies. Here is a list of schemes that apply to purchasing and installing doors and windows.
FENSA, CERTASS and Assure
FENSA, CERTASS and Assure are all associated with the Government’s Competent person schemes. Belonging to one of these schemes is an alternative to Building Control to show the installer’s ability to work according to the Part L Building Regulations for replacement windows and doors.
The self-certification scheme is for replacing old windows and doors only. Being a member of these schemes means there is no need for a separate inspection or assessment from the Local Authority Building Control.
Your installer being a member of one of these schemes is a MUST for replacing windows and glazed doors in order to comply with Building Regulations, of which you MUST receive a certification from one of these schemes upon completion of the installation. They also include an insurance-backed guarantee in the event that a window company ceases trading during the guarantee period.
The Glass and Glazing Federation (GGF)
The GGF is the ‘representative organisation for companies involved in all aspects of the manufacture of flat glass and related products and for installation services for all types of glazing, in the commercial and domestic construction sectors’; this includes FENSA.
For the glazing industry, the GGF keep in touch and informs the Government and decision-makers about industry concerns, legislation and consumer protection.
For its members, they provide events, technical advice, best working practices, technical help, training, Building Regulations & legislation advice, recycling schemes, Insurance Backed Guarantees and the GGF brand and logo use.
Using a company that is a member of the GGF, the homeowner benefits from deposit schemes and conciliation or arbitration services.
The Double Glazing Conservatory Ombudsman Scheme (DGCOS)
The DGCOS aims to protect consumers and improve the reputation of the glazing industry. An ombudsman is independent and provides a dispute resolution service for the consumer.
To be a member, the business must pass an accreditation process for the product (or products) for which they want to be accredited and includes checking members’ finances, competency certificates, and business insurance.
Once you have entered into a contract with a scheme member, you can benefit from a deposit and stage-payment protection insurance, with limitations, an insurance-backed guarantee (IBG), and access to their consumer advice line during installation.
However, be warned! In order to receive protection from the DGCOS scheme, there are conditions, including being a current member of the scheme when you enter into a contract with them to carry out the work, you must pay the member directly and be a domestic property in England, Scotland, Wales or the Isle of Wight. There are many more conditions you must be aware of and adhere to, so make sure you read them all fully. (https://www.dgcos.org.uk/about/protection)
British Fenestration Rating Council (BFRC)
The BFRC is a rating organisation, not the only one, that verifies the energy performance of windows and doors. The rating is shown via a label, such as the one you see for home appliances and EPCs when buying and selling a home.
The BFRC’s role is to assess the windows and doors and give them a rating between A++ and E, which will be depicted on a label with the certified company name and BFRC membership number.
The benefit for the consumer is that it informs the consumer of the energy balance between solar gain and thermal heat loss/air leakage, which means you can compare the performance of various products and ensure they meet building regulations.
CheckaTrade
CheckaTrade is a review website, meaning trade companies pay to list on the site, and customers can leave reviews. It’s a bit like a modern-day Yellow Pages but with the added benefits of checks and reviews. Although not a consumer organisation, they have been included in this list as they offer a guarantee. Their website states: ‘Jobs booked through our platform are guaranteed for 12 months, up to £1,000. Terms and conditions apply.’ Therefore, as with all guarantees, read the small print.
The website is helpful for finding window and door installers in your area, which is becoming increasingly more challenging via the internet due to larger businesses with more marketing resources dominating the search engines. You can also contact us at DWE for help finding a reputable local installer.
Checkatrade states that a ‘tradesperson has passed up to 12 rigorous checks’. They don’t list all 12 checks but they do include that trades must prove they are who they say they are, they check they’ve never been bankrupt, insolvent, struck off a directorship, or subject to a county court judgment, and they must prove that they give their customers consistently exceptional experiences – they do this by spot-checking the reviews left on the website have been left by real people, about real experiences.
Reviews are a powerful tool for both the trade to secure work and the consumer for testimonials, but we are all aware of the practice of fake reviews, and there are always two sides to a story from a disgruntled customer. Therefore, do not assume all reviews are from real customers; read through many reviews for each trade, read between the lines, have the tradesperson respond to the review, check the credentials advertised on their website and double-check the trade via Gov.UK Companies House.
TrustMark
TrustMark is the only government-endorsed scheme for building work in or around your home.
A TrustMark registered business has been vetted to meet its required standards such as through site inspections, financial stability checks, trading records and other company policies such as a suitable complaints procedure, health and safety, the provision of insurance-backed warranty schemes and is committed to good customer service. There is no option for the consumer to leave a review after the work is completed.
The TrustMark benefits for trades include being listed in their online directory, being able to work on government energy efficiency funding schemes, and financial protections for the trade and the consumer.
For the consumer, they have some good advice about how to find a tradesperson. Their directory, however, indicates that they tend to attract building contractors and general builders rather than specialist door and window installers. So do not assume that just because a door and window company is not listed, they are not a reputable trade; Trustmark may just not be the right scheme for them.
Consumer Protection Association (CPA)
The CPA is one of the leading UK consumer protection agencies purely for the home improvement industry, authorised and regulated by the Financial Conduct Authority. They aim to ‘promote consumer trust in professional and qualified tradespeople‘.
For the consumer, they provide fully vetted, quality contractors with an IBG (insurance-backed guarantee) and a deposit protection scheme.
The CPA also vets and inspects their members; part of this vetting procedure includes contacting the customers for feedback, however you do not have access to this.
In addition, there is no option to leave reviews because there is no trade listing! Annoyingly, you must complete a form. You can search by the membership number; however, after checking five companies stating on their website that they were members of the CPA – no membership number was mentioned – you would have to call them to ask for it.
Considering that the CPA aims to ‘promote consumer trust in professional and qualified tradespeople,’ their help finding a tradesperson is not consumer-friendly.
Insurance Backed Guarantee Company (IBG)
The Insurance Backed Guarantee Company (IBG) provides insurance policies designed to protect consumers if the contractor ceases trading and cannot honour the terms of their written guarantee.
Therefore, an IBG is an insurance policy that covers the original guarantee.
IBGs provide protection, subject to the policy terms and conditions, and can be purchased independently through an insurance broker, be provided by the installer, or via a scheme the installer is a member of.
The installer must have registered you for the IBG, and there are many other terms and conditions as with any insurance policy, such as limitation to the overall value you can claim and the period in which you can claim. So ensure you ask for the full terms and conditions and that you have confirmation of the IBG in your name.
DWE advice about double glazing guarantees
How long should double glazing be guaranteed for?
You will come across guarantees from 5-25 years; be aware that the higher guarantees, such as between 10-25 years, will not be the whole door or window but parts of the products. For example, the locks and hardware may be 5 years, the glass 10 years and the frame 25 years. An Insurance Backed Guarantee should also back all guarantees.
Make sure you check your guarantee, as many don’t cover all parts of your installation, and some guarantees only cover the product for the original customer and not when you sell or transfer ownership of your home.
What is the impact of double glazing guarantees on your home’s resale value?
Double glazing guarantees can only add value to your home resale value. Proving that your installation was installed via a competent person scheme, such as FENSA and CERTASS, is also a building regulation requirement for which a certificate must be provided when you sell your home.
What main benefit do homeowners gain from seeking out double glazing guarantees?
Double glazing guarantees provide peace of mind as long as you have done your homework on the scheme offers and ticked all the policy terms and conditions boxes.
How do double glazing guarantees help with the overall energy efficiency of a home?
By buying a product that verifies the energy performance of windows and doors, such as the British Fenestration Rating Council (BFRC), or other independent rating system, you can be assured you are improving your home’s overall energy efficiency.
How long should double glazing be guaranteed for?
Typically, it lasts ten years, but it excludes glass and some other components. The type and quality of guarantee you get depends on the product, the brand and the individual manufacturer.
What is the life expectancy of a double glazing window?
You can expect most well-made and fitted windows to last up to twenty years. The life expectancy depends on its use, wear and tear, and the quality of the components it is made with. For example, windows in dwellings last longer than windows in schools or commercial buildings.
What does a 10-year guarantee cover?
A 10-year guarantee often covers the window frames, seals, and hardware against manufacturing defects—but it can vary widely. Many suppliers only provide a 5-year warranty on the glass itself, because most glass manufacturers don’t offer a full decade of coverage. Always check the specific terms with your installer for any exclusions (like accidental damage, wear and tear, or improper installation). Get in touch with us for advice or carefully check what is covered by your window company.
Is there a double glazing ombudsman?
Yes, the Double Glazing & Conservatory Ombudsman Scheme (DGCOS) does serve as an ombudsman for double glazing companies. They help consumers resolve complaints about member installers by providing free advice, access to vetted professionals, and an alternative dispute resolution (ADR) process. If a dispute remains unresolved after ADR, consumers can escalate it to the independent ombudsman at no cost.
DGCOS also works to uphold high industry standards by ensuring member companies operate professionally and ethically. You can contact them by phone, email, or in person for guidance. However, if you’ve already taken legal action, the ombudsman can’t investigate your complaint further.
As Which outlines in an article, you can also get extra protection if you pay by credit card under the Consumer Credit Act 1974, which includes whole or part payments even if an installer goes out of business before finishing the job.
Unfortunately, Trading Standards has many articles about consumers being scammed by builders, so it is essential to check them out – you are handing over a lot of money, so don’t be charmed. Check all the scheme badges they say they have back to the original provider to ensure they are a member and current. Check out the company on the GOV.UK Companies House to check they are still trading, see how long they have been trading for, and say who they say they are.
With over 35 years of experience in the glazing industry, we are also here to offer help and advice in finding a reputable installer.
As with all double glazing guarantees, warranties and insurance policies, you must check the small print to ensure you meet all the terms and conditions; this often means registering with the scheme once the work is contracted and/or completed and ensuring you have received a certificate or contract.
