What Is FENSA and Why It Matters for Window & Door Work
Part of the ProtectMyQuote Red Flags Guide
If you've had quotes for replacement windows or doors, you've probably seen "FENSA registered" mentioned somewhere in the paperwork. It's one of the more confusing certifications for homeowners, mainly because it's not actually about the quality of the windows themselves — it's about legal compliance, and it matters more than most people realise, especially when it comes to selling a property later.
What to actually look for
What FENSA actually certifies
FENSA (Fenestration Self-Assessment Scheme) is a competent person scheme that allows registered installers to self-certify that replacement windows and doors comply with Building Regulations, without needing a separate visit and sign-off from local council building control. It's specifically about regulatory compliance — insulation values, safety glazing, ventilation — not a quality or workmanship guarantee on its own.
Why it matters when you come to sell your property
When replacement windows or doors are installed without either FENSA certification or council building control sign-off, it can create a genuine problem when you sell the property, because conveyancing solicitors typically ask for proof of compliance. Retrospectively obtaining this after the fact can be inconvenient and sometimes costly, so it's far easier to confirm certification before work starts than to sort it out years later.
FENSA isn't the only scheme — CERTASS is another
FENSA is the best-known competent person scheme for windows and doors, but it isn't the only one — CERTASS operates in a similar way and is also a legitimate route to Building Regulations compliance. What matters is that an installer is registered with one of the recognised schemes, not specifically that it's FENSA by name.
What to actually check before agreeing to a quote
Ask directly whether the installer is FENSA or CERTASS registered, and ask for the certificate to be provided on completion, not just promised verbally. You can also check an installer's registration status directly through the FENSA or CERTASS websites before committing to a quote.
Not sure if your own quote stacks up?
Run it through our free instant check and see how it compares to typical 2026 UK trade prices for your job — in seconds, no name or address needed.
CHECK MY WINDOWS & DOORS QUOTE FREEOptional £1.99 full Quote Protection Check report after your free check
FAQs
Do I legally need FENSA certification for new windows?
You need the work to comply with Building Regulations one way or another — either through a FENSA (or equivalent scheme) certificate from your installer, or through a separate building control application. FENSA is simply the more common, more convenient route most homeowners use.
What happens if my windows weren't FENSA certified when they were installed?
It can cause complications when selling the property, since solicitors typically request proof of compliance. It's usually possible to resolve retrospectively, though this can take time and sometimes cost, which is why checking certification upfront is easier.
Is FENSA the only certification scheme for windows and doors?
No — CERTASS is another recognised competent person scheme covering similar ground. What matters is that your installer is registered with a recognised scheme, not the specific name of it.