Article updated: 30.06.2026
FENSA certificates are one of the key forms of evidence of compliance with Building Regulations for replacement window and door installations in England and Wales. They are not a form of planning permission, they are not a national requirement across the whole UK, and they are not a product indicator for replacement windows or doors. To put it another way, the FENSA scheme is used to confirm compliance for certain replacement window and door installations. If your project falls within FENSA’s scope and you use an installer registered with FENSA, your installer will be able to register your installation and arrange your FENSA certificate after completion.
In this article, we’ll explain what the FENSA certificate covers, when you may require one, how it differs from Building Control, what happens if your installer isn’t FENSA registered, and what documents you may wish to keep for future reference.
What is FENSA?
FENSA is an acronym for Fenestration Self-Assessment Scheme. It is a government-authorised competent person scheme for replacement windows and doors in England and Wales. The scheme was established in 2002, after building regulations had been updated to include requirements for replacement glazing in homes.
The FENSA certificate for windows and doors confirms that the replacement installation has been registered through the FENSA scheme and declared compliant with the relevant Building Regulations. It is not a separate product standard for the glazing itself, but evidence that the work has been completed through a recognised compliance route.
For installations completed after 2014, homeowners may also receive an insurance-backed guarantee, also known as an IBG. This is a separate warranty insurance document issued by an insurance provider or broker, not the same document as the FENSA certificate.
In summary, the FENSA certificate indicates that the installer has replaced the homeowner’s windows and/or doors and that the installation:
- complies with the relevant Building Regulations,
- uses energy-efficient products,
- is registered with the local authority.
Important: FENSA applies only to replacements of external windows and doors in existing residential buildings in England and Wales. It does not cover repairs, sash-only replacements, or installations in new builds, conservatories, porches and similar structures.
Does FENSA apply across the whole UK?
No, please bear in mind that The FENSA route described in this article applies to England and Wales.
Scotland and Northern Ireland have their own building standards and Building Regulations systems, so homeowners there should check the local compliance route before replacing windows or doors. This is why it is better not to treat FENSA as a general “UK certificate” for every project.
What does FENSA cover and not cover?
| FENSA covers | FENSA usually does not cover |
|---|---|
| Replacement windows and doors in existing homes in England and Wales | New builds, extensions, conservatories, porches, commercial properties and repairs where the frame is not replaced |
Why is the FENSA certificate needed?
The first reason you may need a certificate for windows is to confirm that your property has the correct evidence of compliance with building regulations. Replacing windows or doors without the right compliance route can cause problems later, especially if the property is being sold.
The FENSA certificate is proof that the replacement work has been registered and declared compliant through the FENSA route. This is important because windows and doors play a major role in the thermal performance, ventilation, safety and overall comfort of a home.
It is also worth noting that the FENSA certificate for doors and windows can make a difference during the sale of your property. Buyers, solicitors or surveyors often ask for evidence of compliance when replacement windows or doors have been installed. Having the right certificate can help avoid delays and additional questions during the sales process.
Is the certificate for windows obligatory?
There are many questions about the FENSA certificate for windows and doors. The one we hear most often at Fenbro is related to whether the certificate is actually required. The safest way to explain it is this: for replacement windows and doors in England and Wales, the key issue is having the correct evidence of compliance with building regulations. A FENSA certificate is one of the most common ways to provide this evidence, but it is not the only possible route.
In practice, compliance can usually be confirmed through:
- a FENSA certificate,
- a certificate from another competent person scheme,
- or approval through the local authority Building Control route.
If you use an installer registered with a competent person scheme, they can self-certify the work and register it on your behalf. If you do not use a registered installer, you may need to apply for building regulations approval yourself through Building Control.
Such certificates are usually not required for every type of project. FENSA generally does not apply to:
- new builds,
- extensions,
- conservatories,
- orangeries,
- conversions of any type, e.g. barn conversion,
- commercial premises,
- listed buildings,
- external porches,
- detached garages,
- sheds,
- caravans,
- mobile homes,
- and some repair work.
The certificate is mainly important when the property is being sold. Buyers and solicitors often ask for evidence of compliance when replacement windows or doors have been installed. Without the right documentation, the sale process may become more complicated or delayed.
FENSA vs Building Control – what is the difference?
| Aspect | FENSA / competent person route | Building Control route |
|---|---|---|
| Who handles it? | FENSA Approved Installer | Homeowner, contractor or installer |
| Main purpose | Self-certify relevant replacement work | Local authority approval or checks |
| What do you receive? | FENSA certificate | Building Control completion or compliance document |
| When is it used? | Installer is in the scheme | Installer is not in a scheme or the project needs Building Control |
| Is it planning permission? | No | No |
The 5 most common mix-ups before ordering windows
- Assuming FENSA is the same as Building Control.
- Assuming FENSA applies across the whole UK.
- Assuming FENSA is planning permission.
- Assuming FENSA is a product badge for the window itself.
- Assuming the quote should come before the compliance route is clear.
These mistakes are easy to make, so it is best to check the compliance route before ordering.
How to get the FENSA certificate?
The easiest way to obtain a certificate for replacement windows or doors is to use an installation company registered with FENSA. A FENSA Approved Installer can self-certify the work, register the installation with the local authority and arrange the FENSA certificate after the work is completed.
According to GOV.UK guidance for competent person schemes, the homeowner should receive a certificate within 8 weeks of completion. In most cases, the cost of registration is included in the installer’s quote, but it is always worth confirming this before the work starts.
If you lose your certificate for windows or doors, you can order a replacement through the official FENSA website. The replacement certificate fee may change over time, so it is best to check the current cost directly on the FENSA website.
Remember that you can also use the official FENSA website if you want to perform a FENSA certificate check for your chosen property. To see if a certificate is linked to your address, simply enter your house number and postcode on the FENSA website.
How long is the FENSA certificate for front doors and windows valid?
A FENSA certificate is issued for a property and not for a specific person. This means that it stays linked to the windows and doors it covers and should be passed on to the new owner when the property is sold. The certificate itself does not expire when the property is sold. It remains important evidence that the replacement installation was registered and declared compliant with the relevant Building Regulations through the FENSA scheme.
Please also remember that a FENSA certificate and an installer’s warranty or insurance-backed guarantee are not the same document. The certificate confirms compliance and registration of the installation, while the warranty or insurance-backed guarantee relates to cover provided for the work.
How to get a certificate for windows if the installation was carried out by a company or person who is not on the FENSA list?
The fact that an installation company or fitter is not registered on the FENSA list does not automatically mean that they do not comply with the regulations, or that you should not use their services. However, it does mean that they cannot issue a FENSA certificate for the work. If the fitter you wish to use is not registered with FENSA or another competent person scheme, you may still obtain evidence of compliance through the Building Control route. In this case, you should contact your local Building Control department before the work starts. You may need to submit a building notice or full plans application and pay the relevant fee. Building Control may then inspect the work and, if everything is compliant, issue the appropriate completion or compliance documentation.
This is not a FENSA inspection. It is a Building Control process. Because fees and procedures can vary depending on the local authority and the type of work, it is best to check the exact requirements before the installation begins.
What happens if the windows are not FENSA-certified?
Not having a FENSA certificate can be quite a problem, especially when you want to sell your property. But don’t panic when you find that you can’t get it for your joinery – in many cases, this issue can still be solved. You may have two options.
The first is to contact your local authority Building Control department and ask whether a retrospective Building Regulations application is possible. If the inspection confirms that the work carried out is correct and that the windows and doors meet the relevant requirements, Building Control may issue the appropriate completion or compliance documentation. Otherwise, you may be asked to make changes or, in some cases, replace the joinery.
The second way is to consider indemnity insurance, usually with advice from your solicitor. This option is often discussed when the installation was completed some time ago and the missing certificate becomes a problem during a property sale. Such insurance may protect against certain financial risks connected with missing Building Regulations documentation, but it does not confirm that the installation itself is compliant.
Because procedures, timing and fees can vary depending on the local authority and the individual case, it is best to check the exact requirements with Building Control or your solicitor before taking action.
Can imported windows still be used on a FENSA-compliant project?
Yes. Imported windows, including Polish windows, can be used on a FENSA-compliant project in England and Wales. The country of origin is not the key issue. What matters is the exact product specification, the quality of the installation and the correct compliance route.
Polish windows and doors are a common choice in England and Wales. Both individual customers and large investors order joinery from Fenbro thanks to the wide range of products available, strong technical parameters and competitive prices. However, FENSA is not a product quality mark assigned to windows because they are made in Poland, the UK or any other country.
A FENSA certificate relates to the replacement installation, not simply to the product itself. Fenbro windows and doors can be specified to meet demanding performance, thermal and design requirements, but compliance for a specific project depends on how the installation is registered and approved. To confirm compliance, the installation should be registered by a FENSA Approved Installer, another competent person scheme, or approved through the local Building Control route.
Compliance with Building Regulations is extremely important, especially if you plan to sell your property in the future. Buyers and solicitors often ask for evidence that replacement windows or doors were installed and registered correctly. If you are planning to use imported windows, including Polish windows from Fenbro, make sure you check the compliance route before the work starts.
What documents should you keep after installation?
After replacing windows or doors, keep all documents connected with the project in one place. This may include:
- a FENSA certificate or another compliance certificate,
- Building Control documentation, if this route was used,
- the invoice,
- the order specification,
- the product warranty,
- and an insurance-backed guarantee, where applicable.
These documents may be useful in the future, for example in case you want to sell your property.
Frequently Asked Questions (FAQ)
What is a FENSA certificate?
It is a document you may need after replacing windows or doors in England and Wales. In simple terms, it shows that the installation was registered through FENSA and declared compliant with the relevant Building Regulations.
Do I need a FENSA certificate to replace windows?
Not always exactly a FENSA certificate, but you do need the right paperwork. If your replacement windows or doors need to comply with Building Regulations, you should have evidence of that. FENSA is one of the easiest routes when your installer is FENSA registered.
Does FENSA apply in Scotland?
No. FENSA is for England and Wales. Scotland has its own building standards, so the process is different there.
Does FENSA apply in Northern Ireland?
No, Northern Ireland has its own Building Regulations system – FENSA is only for England and Wales. So if your property is in Northern Ireland, you should check the local route instead of assuming FENSA applies.
Is FENSA the same as Building Control?
No. They are connected with the same general topic – compliance – but they are not the same route. FENSA lets approved installers self-certify certain replacement window and door installations. Building Control is the local authority route, usually used when the installer cannot certify the work through a competent person scheme.
What if my installer is not FENSA registered?
That does not automatically mean trouble. It just means they cannot give you a FENSA certificate. You may still be able to get the work signed off through another competent person scheme or through Building Control. The important thing is to check this before the work starts, not after.
How long does it take to get the certificate?
According to GOV.UK guidance, the certificate should reach the homeowner within 8 weeks of completion. If you are still waiting after that, the first person to contact is usually your installer.
Can I sell my house without a FENSA certificate?
Possibly, yes. But it may make things slower and more stressful. Buyers and solicitors often ask for proof that replacement windows or doors were installed properly. If you do not have a FENSA certificate, they may ask for another certificate, Building Control documents or advice from your solicitor.
What does FENSA not cover?
FENSA does not cover every window or door job. It applies to replacement external windows and doors in existing homes in England and Wales. New builds, new extensions, new conservatories, porches, commercial buildings and simple repairs are outside its scope.
Do imported windows stop me getting a FENSA-compliant installation?
No, imported windows are not the issue by themselves. What matters is whether the product specification is right, the installation is done properly and the correct compliance route is followed. Polish windows from Fenbro can be used in compliant projects, as long as the project meets the relevant requirements.
