If you’ve recently replaced windows or doors in your home, or are looking to buy or sell a property in the UK, you’ve likely come across the term FENSA certificate. But what exactly is it, and why is it so important? In this 2025 guide, we’ll break down everything you need to know about the FENSA certificate – from what it covers to how to get one.
What is a FENSA certificate?
FENSA stands for Fenestration Self-Assessment Scheme. It’s a government-authorised scheme that allows window and door installers in England and Wales to self-certify compliance with Building Regulations.
If your windows or doors were replaced (not newly installed) after 1st April 2002, a FENSA certificate proves the work meets current energy efficiency and safety standards without needing a separate inspection from your local authority.
Why is a FENSA certificate important?
A FENSA certificate is more than just a piece of paper—it’s legal proof that:
The installation complies with relevant UK Building Regulations.
The work was carried out by a FENSA-approved installer.
Your home’s energy efficiency and safety standards are protected.
You’ll also need this certificate when selling your home, as conveyancers will request evidence that any replacement doors or windows were installed legally and properly.
When do you need a FENSA certificate?
You need a FENSA certificate if:
You’ve had external doors or windows replaced (not newly installed) in a residential property in England or Wales.
The installation was carried out by a FENSA-registered company.
You do not need one for:
New build properties (covered under different regulations).
Conservatories or porches (unless their windows or doors are replaced separately).
DIY installations or work completed by non-FENSA tradespeople (though these will need Building Control approval instead).
What does a FENSA certificate cover?
Your FENSA certificate proves that your windows and doors:
Meet energy performance and thermal efficiency standards.
Are fitted with the correct safety glazing and ventilation.
Comply with Building Regulations for fire escape access (if required).
Have been installed by a FENSA-approved contractor.
Not covered:
Manufacturer faults or warranties on the window units themselves.
Decorative or style choices.
Quality of materials (only compliance with regs).
What if you don’t have a FENSA certificate?
If you don’t have a FENSA certificate for work carried out after 2002, you might:
Struggle to sell your home, as the buyer’s solicitor will request it.
Need indemnity insurance to cover potential enforcement by the local authority.
Have to apply for a retrospective Building Control inspection, which can be time-consuming and costly.
How to check if your property has a FENSA certificate
You can check if your property has a FENSA certificate by visiting the official FENSA certificate checker.
You’ll need to provide:
The property’s postcode
Installer name or FENSA ID (if known)
Approximate installation date
How to get a replacement FENSA certificate
If you’ve misplaced your certificate, don’t worry—you can order a replacement online:
Go to the FENSA website
Enter your property details
Pay a small fee (around £25–£30)
Receive your certificate via email or post
Most certificates are delivered within a few days.
How to get a FENSA certificate retrospectively
If your installer was not FENSA-approved, you can’t get a FENSA certificate. Instead, you have two options:
Contact Building Control for a retrospective inspection and approval certificate
Take out indemnity insurance, especially if you’re planning to sell
This insurance is usually arranged by your solicitor and costs around £100–£200, depending on your circumstances.
FENSA vs. Certass – what’s the difference?
Both FENSA and Certass are government-approved self-certification schemes. The main differences are:
FENSA is the more widely recognised name
Both provide proof of compliance with Building Regulations
Solicitors tend to ask for FENSA, but will usually accept Certass certificates as valid
Choosing a FENSA-approved installer
Always check whether your window or door installer is FENSA-registered. Doing so ensures:
Compliance with Building Regs
You’ll automatically receive a FENSA certificate
Work is insured and backed by a guarantee
Search for approved installers by postcode on the FENSA website.
FAQs
What is a FENSA certificate?
It’s a document proving that replacement windows and doors were installed by a FENSA-registered company in compliance with UK Building Regulations.
Do I need a FENSA certificate to sell my house?
Yes. It’s commonly requested by buyers’ solicitors and may delay or complicate the sale if missing.
How can I get a FENSA certificate online?
Use the FENSA website’s certificate checker to search your address and order a replacement for a small fee.
Can I sell my home without a FENSA certificate?
You can, but you may need to provide indemnity insurance or apply for Building Control approval retrospectively.
How much does a FENSA certificate cost?
A replacement typically costs £25–£30.
What happens if I lost my FENSA certificate?
You can order a new one through the FENSA website using your address details.
Is a FENSA certificate legally required?
Yes, if the windows or doors were replaced (not newly installed) after 1st April 2002.
Final thoughts
A FENSA certificate offers more than peace of mind—it’s a vital legal document when maintaining, improving, or selling your property. Whether you’re replacing windows, planning a sale, or checking up on a past installation, having this certificate in place helps ensure everything is compliant, above board, and ready for a smooth transaction.